2012 March 28 Wednesday
Sitting Too Long Boosts Death Risks

Suggested change in a Bob Marley song's lyrics: Get up, stand up, stand up for your life.

Standing up more often may reduce your chances of dying within three years, even if you are already physically active, a study of more than 200,000 people published in Archives of Internal Medicine today shows.

The study found that adults who sat 11 or more hours per day had a 40% increased risk of dying in the next three years compared with those who sat for fewer than four hours a day. This was after taking into account their physical activity, weight and health status.

"These results have important public health implications," said study lead author Dr Hidde van der Ploeg, a senior research fellow at the University of Sydney's School of Public Health.

I try to get up and take walks every few hours. Lately I've got some hand exercisers that I use while I walk. I also use a much stronger version of such exercisers to work both arms to close one as a way to get upper arm and chest exercise. Portable work-out equipment. Definitely needed for people who spend many hours a day in front of a computer.

By Randall Parker    2012 March 28 10:29 PM   Entry Permalink | Comments (15)
2012 February 23 Thursday
Over 4 Hours Exercise Per Week Prevents Work Burnout

Tel Aviv University researchers find that people that get at least 4 hours of exercise per week experienced the least amount of burnout and depression.

The participants were divided into four groups: one that did not engage in physical activity; a second that did 75 to 150 minutes of physical activity a week; a third that did 150 to 240 minutes a week; and a fourth that did more than 240 minutes a week.

Depression and burnout rates were clearly the highest among the group that did not participate in physical activity. The more physical activity that participants engaged in, the less likely they were to experience elevated depression and burnout levels during the next three years. The optimal amount of physical activity was a minimum of 150 minutes per week, where its benefits really started to take effect.

In those who engaged in 240 minutes of physical activity or more, the impact of burnout and depression was almost nonexistent. But even 150 minutes a week will have a highly positive impact, says Dr. Toker, helping people to deal with their workday, improving self-efficacy and self-esteem, and staving off the spiral of loss.

I've started incorporating a lot more short periods of exercise into the course of my day. Sometimes I'll do push-ups right after I wake up or use hand exercise devices when I'm sitting around reading or walking. This works well. I don't have to block off large periods of time.

By Randall Parker    2012 February 23 09:33 PM   Entry Permalink | Comments (10)
2012 February 08 Wednesday
Physically Active People Feel Better

Want to feel better? Get some exercise. Exercise makes you high.

People who are more physically active report greater levels of excitement and enthusiasm than people who are less physically active, according to Penn State researchers. People also are more likely to report feelings of excitement and enthusiasm on days when they are more physically active than usual.

"You don't have to be the fittest person who is exercising every day to receive the feel-good benefits of exercise," said David Conroy, professor of kinesiology. "It's a matter of taking it one day at a time, of trying to get your activity in, and then there's this feel-good reward afterwards."

Conroy added that it often is hard for people to commit to an exercise program because they tend to set long-term rather than short-term goals.

"When people set New Year's resolutions, they set them up to include the entire upcoming year, but that can be really overwhelming," he said. "Taking it one day at a time and savoring that feel-good effect at the end of the day might be one step to break it down and get those daily rewards for activity. Doing this could help people be a little more encouraged to stay active and keep up the program they started."

You might argue this is obvious. Yet many obviously good practices are too often forgotten and not done. So the purpose of this post is a reminder: Think back on all those times you've exercised and felt better. You can get that higher feeling today if you just make yourself do some exercise. Even some quick push-ups will help.

By Randall Parker    2012 February 08 10:51 PM   Entry Permalink | Comments (12)
2011 September 03 Saturday
Exercise Tells Stem Cells To Become Bone, Not Fat

Tell all your mouse friends. Yet another reason for mice to get on that treadmill and run like mad.

HAMILTON Sept. 1, 2011 – McMaster researchers have found one more reason to exercise: working out triggers influential stem cells to become bone instead of fat, improving overall health by boosting the body's capacity to make blood.

The body's mesenchymal stem cells are most likely to become fat or bone, depending on which path they follow.

Using treadmill-conditioned mice, a team led by the Department of Kinesiology's Gianni Parise has shown that aerobic exercise triggers those cells to become bone more often than fat.

The exercising mice ran less than an hour, three times a week, enough time to have a significant impact on their blood production, says Parise, an associate professor.

Does this result apply to humans? Probably. So the next time a dog tries to get you to go running take his advice. He's obviously up on the scientific research on exercise.

By Randall Parker    2011 September 03 07:12 PM   Entry Permalink | Comments (5)
2011 August 17 Wednesday
15 Minutes Daily Exercise Adds 3 Years To Life

Even if the exercise was of light intensity just 15 minutes of exercise a day was found to extend life expectancy 3 years among Taiwanese.

HOUSTON -- Taiwanese who exercise for 15 minutes a day, or 92 minutes per week, extended their expected lifespan by three years compared to people who are inactive, according to a study published today in The Lancet.

"Exercising at very light levels reduced deaths from any cause by 14 percent," said study senior author Xifeng Wu, M.D., Ph.D., professor and chair of The University of Texas MD Anderson Cancer Center Department of Epidemiology. "The benefits of exercise appear to be significant even without reaching the recommended 150 minutes per week based on results of previous research."

All the way up to 100 minutes of exercise per day more exercised translated into additional reduction of risk of death.

Lead author Chi-Pang Wen, M.D., of the National Health Research Institutes of Taiwan, and colleagues also found that a person's risk of death from any cause decreased by 4 percent for every additional 15 minutes of exercise up to 100 minutes a day over the course of the study. Those exercising for 30 minutes daily added about four years to life expectancy.

If you live just a mile from some place you now drive to consider walking instead. Want to have a conversation with a friend? Do it while walking.

By Randall Parker    2011 August 17 11:36 PM   Entry Permalink | Comments (7)
2011 January 10 Monday
Higher Cardiac Risk From Watching TV Or Computer

Couch potatoes and web surfers beware.

Spending too much leisure time in front of a TV or computer screen appears to dramatically increase the risk for heart disease and premature death from any cause, perhaps regardless of how much exercise one gets, according to a new study published in the January 18, 2011, issue of the Journal of the American College of Cardiology. Data show that compared to people who spend less than two hours each day on screen-based entertainment like watching TV, using the computer or playing video games, those who devote more than four hours to these activities are more than twice as likely to have a major cardiac event that involves hospitalization, death or both.

Speaking as someone who spends hours every night surfing the web looking for post content: this is not good. We need a way to surf the web while walking around. Virtual reality goggles? But you still need a way to walk safely while surfing the web. How to solve this problem?

By Randall Parker    2011 January 10 09:57 PM   Entry Permalink | Comments (18)
2010 November 29 Monday
Walk, Don't Run For Lower Osteoarthritis Risk

Running too much degenerates cartilage but walking probably cuts osteoarthritis risk.

CHICAGO – People at risk for osteoarthritis may be able to delay the onset of the disease or even prevent it with simple changes to their physical activity, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA).

"According to the results of our study, participating in a high-impact activity, such as running, more than one hour per day at least three times a week appears associated with more degenerated cartilage and potentially a higher risk for development of osteoarthritis," said the study's senior author Thomas M. Link, M.D., professor of radiology and chief of musculoskeletal imaging at the University of California, San Francisco (UCSF). "On the other hand, engaging in light exercise and refraining from frequent knee-bending activities may protect against the onset of the disease."

Count me skeptical of the health benefits of long range running. Stephan Guyenet makes a lot of sense on exercise.

By Randall Parker    2010 November 29 11:19 PM   Entry Permalink | Comments (2)
Walking Slows Brain Decline

Take a walk for your brain.

CHICAGO – Walking may slow cognitive decline in adults with mild cognitive impairment (MCI) and Alzheimer's disease, as well as in healthy adults, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA).

"We found that walking five miles per week protects the brain structure over 10 years in people with Alzheimer's and MCI, especially in areas of the brain's key memory and learning centers," said Cyrus Raji, Ph.D., from the Department of Radiology at the University of Pittsburgh in Pennsylvania. "We also found that these people had a slower decline in memory loss over five years."

Put on your walking shoes and start hoofing it.

The findings showed across the board that greater amounts of physical activity were associated with greater brain volume. Cognitively impaired people needed to walk at least 58 city blocks, or approximately five miles, per week to maintain brain volume and slow cognitive decline. The healthy adults needed to walk at least 72 city blocks, or six miles, per week to maintain brain volume and significantly reduce their risk for cognitive decline.

Over five years, MMSE scores decreased by an average of five points in cognitively impaired patients who did not engage in a sufficient level of physical activity, compared with a decrease of only one point in patients who met the physical activity requirement.

Need walking music? Try Gerry Mulligan's 1956 "Walking Shoes".

By Randall Parker    2010 November 29 11:00 PM   Entry Permalink | Comments (0)
2010 November 25 Thursday
91 Year Old Woman Sets Athletic Records

91 year old Canadian Olga Kotelko holds many athletic records for her age group.

Masters competitions usually begin at 35 years, and include many in their 60s, 70s and 80s (and a few, like Kotelko, in their 90s, and one or two over 100). Of the thousands who descended on Lahti, hundreds were older than 75. And the one getting all the attention was Kotelko. She is considered one of the world’s greatest athletes, holding 23 world records, 17 in her current age category, 90 to 95.

...

At last fall’s Lahti championship, Kotelko threw a javelin more than 20 feet farther than her nearest age-group rival. At the World Masters Games in Sydney, Kotelko’s time in the 100 meters — 23.95 seconds — was faster than that of some finalists in the 80-to-84-year category, two brackets down.

Her 16.1 foot shot-put record compares with the world record for all women of 74.3 feet. So she's way below what a youthful athlete can do. But to do what she can do at age 91 is extremely rare.

People in their late 60s and beyond lose most of their muscle mass. Kotelko is losing hers much more slowly. So researchers who study mitochondria (a sort of cell within a cell that breaks down sugars for energy) are looking for hints that perhaps her mitochondria are not aging as rapidly. Early indications are that, yes, her mitochondria in her muscles are in much better shape than expected for someone her age.

The article is worth reading. It starts to get scientifically interesting on page 3 where it starts to survey some of the theories of aging. One question a scientist brings up: Is it that the muscles are aging or that neurons are losing their connections to the muscles? That's an important question to figure out because it would guide choice of rejuvenation therapies. Would youthful muscle stem cells do the trick? Or youthful nerve stem cells? Or some sort of drug to guide neurons to reconnect with muscle strands?

The body is made up of parts just like a car is made up of parts. Develop the ability to replace worn out body parts and you gain the ability to keep an old body going just like replacing car parts enables you to keep an old car on the road.

By Randall Parker    2010 November 25 06:19 PM   Entry Permalink | Comments (0)
2010 November 18 Thursday
Some Get Little Benefit From Exercise?

Some of you are feeling very hopeful from that headline. Might be pointless to go jogging or lift weights? Finally escape from physical effort. Finnish researchers found that some people do not increase muscle mass or aerobic capacity or insulin sensitivity thru exercise.

Recently, researchers in Finland made the discovery that some people’s bodies do not respond as expected to weight training, others don’t respond to endurance exercise and, in some lamentable cases, some don’t respond to either. In other words, there are those who just do not become fitter or stronger, no matter what exercise they undertake.

Some people do not build up muscles when they exercise. Some do not improve their vascular capacity. One could go thru exercise programs and measure this about yourself. This is about the only way to find out until genetic testing becomes cheap enough to enable the discovery of all the genetic variants that control body response to exercise.

You've heard about nutrigenomics, right? That's where genetic testing will some day (sooner please) tell us individually what our best diet would be. Well, not sure how to make this into a single word but the same is going to happen for exercise. Exercisogenomics? Any suggestions? Or does some word already exist for this purpose?

Of course, your genetic results might bring unwanted news: Little benefit from exercise plus high risks of heart disease, stroke, and type II insulin-insensitive diabetes. We need gene therapies and cell therapies that'll make our bodies not need exercise and have much lower risk of a large assortment of diseases.

By Randall Parker    2010 November 18 08:49 PM   Entry Permalink | Comments (15)
2010 October 24 Sunday
Beware Marathon Heart Injury

If you haven't built up to a marathon with a lot of training you can inflict heart damage on yourself that'll take up to 3 months to heal.

Montreal - Is running a marathon good for you or can it damage the heart?

A team of researchers and runners from the Heart and Stroke Foundation have come up with a practical way of answering the question. They used data from magnetic resonance imaging (MRI) to find out what is really going on in the marathoner's heart as the kilometers pile up.

"Marathon runners can be a lot less fit than they think," Dr. Eric Larose today told the Canadian Cardiovascular Congress 2010, co-hosted by the Heart and Stroke Foundation and the Canadian Cardiovascular Society.

Lack of real aerobic fitness may directly impact the ways the heart organizes itself to survive the stress of marathon running, says Dr. Larose.

His research found that the magnitude of abnormal heart segments was more widespread and significant in a group of less fit runners. During the marathon, they had signs the heart might be at greater risk of damage than that of runners who had better training or at least had better exercise capacity.

It can take up to 3 months to recover from exercise-induced heart injury. I had no idea.

"Without proper training, marathon running can damage your heart. Fortunately the exercise-induced injury is reversible over time," said Dr. Larose. "But it could take up to three months to completely recover."

Any reader have a better understanding of just how severe exercise injury to muscles can be? Does an 18 year old need to worry? A 40 year old? When does it become a concern?

By Randall Parker    2010 October 24 11:33 PM   Entry Permalink | Comments (19)
2010 October 13 Wednesday
Walk To Cut Memory Decline In Half

6 to 9 miles per week will reduce the rate of loss of gray matter volume and lower risk of memory problems.

For the study, 299 dementia-free people recorded the number of blocks they walked in one week. Then nine years later, scientists took brain scans of the participants to measure their brain size. After four more years, the participants were tested to see if they had developed cognitive impairment or dementia.

The study found that people who walked at least 72 blocks per week, or roughly six to nine miles, had greater gray matter volume than people who didn't walk as much, when measured at the nine-year time point after their recorded activity. Walking more than 72 blocks did not appear to increase gray matter volume any further.

By four years later, 116 of the participants, or 40 percent, had developed cognitive impairment or dementia. The researchers found that those who walked the most cut their risk of developing memory problems in half.

If you walk 3 miles per hour then that's about 2 to 3 hours walking per week. You doing that? if not, what could you add to your routine to get that amount of walking in per week?

By Randall Parker    2010 October 13 10:45 PM   Entry Permalink | Comments (4)
2010 August 11 Wednesday
Muscle Fatigue Key To Muscle Growth

The needed fatigue can be achieved by lifting lighter weights.

HAMILTON, ON. August 10, 2010 – Current gym dogma holds that to build muscle size you need to lift heavy weights. However, a new study conducted at McMaster University has shown that a similar degree of muscle building can be achieved by using lighter weights. The secret is to pump iron until you reach muscle fatigue.

Pump it until you can't pump any longer. Lighter weights require more repetitions to reach fatigue. So one argument for heavier weights is speed of the work-out. Though you can go thru each repetition with lighter weights more rapidly.

"Rather than grunting and straining to lift heavy weights, you can grab something much lighter but you have to lift it until you can't lift it anymore," says Stuart Phillips, associate professor of kinesiology at McMaster University. "We're convinced that growing muscle means stimulating your muscle to make new muscle proteins, a process in the body that over time accumulates into bigger muscles."

You can read the full study on Plos One.

What do any intense weight-lifters think of this result?

By Randall Parker    2010 August 11 10:56 PM   Entry Permalink | Comments (12)
2010 July 22 Thursday
Get Out Of Your Seat Or Die

We did not evolve to sit. Just like there's a Paleo Diet to bring us back to the diet evolved to eat we need Paleo Furniture for our workplaces. Office chairs should be relabeled death chairs.

To explore the association between sitting time and mortality, researchers led by Alpa Patel, Ph.D. analyzed survey responses from 123,216 individuals (53,440 men and 69,776 women) who had no history of cancer, heart attack, stroke, or emphysema/other lung disease enrolled in the American Cancer Society's Cancer Prevention II study in 1992. They examined the amount of time spent sitting and physical activity in relation to mortality between 1993 and 2006. They found that more leisure time spent sitting was associated with higher risk of mortality, particularly in women. Women who reported more than six hours per day of sitting were 37 percent more likely to die during the time period studied than those who sat fewer than 3 hours a day. Men who sat more than 6 hours a day were 18 percent more likely to die than those who sat fewer than 3 hours per day. The association remained virtually unchanged after adjusting for physical activity level. Associations were stronger for cardiovascular disease mortality than for cancer mortality.

Think you can safely sit for many hours if you just get yourself a Hermann Miller Aeron chair then you are all set to sit for long hours? Nope, not that easy. Sitting is the problem. Worse yet, the classic 90 degree sitting angle is bad. Yup, all that advice about sitting up straight and rectangular was wrong. Those ram-rod straight sitters were all damaging their metabolism. Anyone know, does the Herman Miller Embody chair allow you to tilt back to 120 or 135 degrees? It appears to support more tilting back than the Aeron. But I can't tell how much from pictures.

Sitting combined with not exercising is an even speedier way to meet the Grim Reaper.

When combined with a lack of physical activity, the association was even stronger. Women and men who both sat more and were less physically were 94% and 48% more likely, respectively, to die compared with those who reported sitting the least and being most active.

"Several factors could explain the positive association between time spent sitting and higher all-cause death rates," said Dr. Patel. "Prolonged time spent sitting, independent of physical activity, has been shown to have important metabolic consequences, and may influence things like triglycerides, high density lipoprotein, cholesterol, fasting plasma glucose, resting blood pressure, and leptin, which are biomarkers of obesity and cardiovascular and other chronic diseases."

Is all that sitting killing us? Some researchers think so. The idea is that Exercise doesn't cancel out the changes in muscles that come from extended lack of use.

Hamilton, like many sitting researchers, doesn't own an office chair. "If you're standing around and puttering, you recruit specialized muscles designed for postural support that never tire," he says. "They're unique in that the nervous system recruits them for low-intensity activity and they're very rich in enzymes." One enzyme, lipoprotein lipase, grabs fat and cholesterol from the blood, burning the fat into energy while shifting the cholesterol from LDL (the bad kind) to HDL (the healthy kind). When you sit, the muscles are relaxed, and enzyme activity drops by 90% to 95%, leaving fat to camp out in the bloodstream. Within a couple hours of sitting, healthy cholesterol plummets by 20%.

I've gotten in the habit of getting up and walking around at least once every 2 hours. I'd really like a more flexible work environment that would make it easier to shift between sitting and standing during the course of the day.

Update: Anyone used the Treadmill TrekDesk? How about the Steelcare Jump chair?

By Randall Parker    2010 July 22 09:58 PM   Entry Permalink | Comments (32)
2010 May 09 Sunday
More Walking Means Less Metabolic Syndrome

You've got to step it up for good health. 5 miles of walking per day will cut your risk of Metabolic Syndrome (high blood pressure, insulin-resistant diabetes, and other bad things) by about two thirds.

Using data from the U.S. NHANES 2005-06, a team of investigators from the Pennington Biomedical Research Center, Baton Rouge, Louisiana, analyzed a total sample of 1446 subjects, 523 with MetS and 923 without MetS,. These subjects wore high-quality accelerometers and their activity levels placed them into three step-defined physical activity categories: sedentary (< 5000 steps/day), low-to-somewhat-active (5000-9999 steps/day) and active-to-highly-active (=10000 steps/day).

Some web sites say that an average person will cover a mile in 2000 steps. So the most active people are covering 5 miles on foot every day. I am curious to know how they do this. Walk to work? Or walk a great among while at work? Postal delivery people should have pretty low rates of Metabolic Syndrome.

"Even though public health recommendations focus primarily on the accumulation of time spent in moderate-to-vigorous physical activity, the total volume of physical activity as measured by steps/day was shown to be related to positive health outcomes," lead investigator Peter T. Katzmarzyk, PhD, commented. "Adults who maintain an active lifestyle by accumulating more steps are likely to have a lower prevalence of MetS and its individual CVD risk factors. Although other concomitant lifestyle behaviors may influence this lower prevalence, the evidence presented here on steps/day and metabolic syndrome, and elsewhere on physical activity and other health and disease states, suggest that it is a fundamental component of daily living."

Compared to the sedentary group, odds of having MetS were lower for each higher category of daily steps. In the total sample, the odds of having MetS were 40% lower for the "low-to-somewhat-active" and 72% lower for the "active-to-highly-active" groups compared to the sedentary group. Among men, the odds of MetS were 24% lower in the "low-to-somewhat-active," although not significant, and it was 69% lower in those categorized in the "active-to-highly-active" compared to the sedentary group. For the women, those categorized as "low-to-somewhat-active" had 53% lower odds and those in the "active-to highly- active" group had 72% lower odds of having MetS compared to the sedentary group.

Stepping out makes you skinnier.

Higher levels of steps/day were associated with significantly lower odds of having at-risk CVD profiles for the total sample, and also separately for men, and women. In the total population, each additional 1000 steps/day was associated with an 8%-13% reduction in the odds of high waist circumference, a low level of HDL-cholesterol, and high levels of triglycerides. For men, each additional 1000 steps/day was associated with a 6%-11% reduction in odds of high waist circumference, a low level of HDL-cholesterol, and high levels of triglycerides. For women, each additional 1000 steps/day was associated with a 6%-17% reduction in the odds of high waist circumference, a low level of HDL-cholesterol, and high levels of triglycerides.

I walked to work for several months last year until the days got too short and my walks in both directions were in darkness. Haven't gotten back to walking to work yet this year. I find the walk to work less pleasant than the walk home because in the morning I'm in a rush and get to work later when walking.

Update: Since extended amounts of sitting harm one's health it could be that some of the benefit from taking many steps in the day is it means you spend less time sitting.

By Randall Parker    2010 May 09 11:35 PM   Entry Permalink | Comments (21)
2010 January 11 Monday
Exercise Helps With Mild Cognitive Impairment

Folks with mild cognitive impairment are helped by exercise.

Moderate physical activity performed in midlife or later appears to be associated with a reduced risk of mild cognitive impairment, whereas a six-month high-intensity aerobic exercise program may improve cognitive function in individuals who already have the condition, according to two reports in the January issue of Archives of Neurology, one of the JAMA/Archives journals.

The problem with this result is the (usually insurmountable) challenge of trying to get old folks to change their ways. Heck, try to get someone middle aged to take up regular exercise if they aren't already doing it. I predict low odds of success.

Old folks who are mildly cognitively impaired strike me as even less likely to change their ways than old folks who are still playing with a full deck of mental cards. I'd lay better odds for old folks who are living in facilities that have lots of other old folks around and exercise sessions hosted by trainers. If you can manage to convince an older loved one to get into regular exercise real benefits are probably awaiting.

Mild cognitive impairment is an intermediate state between the normal thinking, learning and memory changes that occur with age and dementia, according to background information in one of the articles. Each year, 10 percent to 15 percent of individuals with mild cognitive impairment will develop dementia, as compared with 1 percent to 2 percent of the general population. Previous studies in animals and humans have suggested that exercise may improve cognitive function.

In one article, Laura D. Baker, Ph.D., of the University of Washington School of Medicine and Veterans Affairs Puget Sound Health Care System, Seattle, and colleagues report the results of a randomized, controlled clinical trial involving 33 adults with mild cognitive impairment (17 women, average age 70). A group of 23 were randomly assigned to an aerobic exercise group and exercised at high intensity levels under the supervision of a trainer for 45 to 60 minutes per day, four days per week. The control group of 10 individuals performed supervised stretching exercises according to the same schedule but kept their heart rate low. Fitness testing, body fat analysis, blood tests of metabolic markers and cognitive functions were assessed before, during and after the six-month trial.

A total of 29 participants completed the study. Overall, the patients in the high-intensity aerobic exercise group experienced improved cognitive function compared with those in the control group. These effects were more pronounced in women than in men, despite similar increases in fitness. The sex differences may be related to the metabolic effects of exercise, as changes to the body's use and production of insulin, glucose and the stress hormone cortisol differed in men and women.

I happen to live close enough to stores to walk to them. I walk for many errands. I think getting exercise while doing tasks you want to get done is a lot more sustainable way to get more exercise. If you can find higher exercise ways to do things that need doing then you can get real benefits.

If you live many miles from stores and don't have any high exercise chores that need doing then consider getting a high energy dog. The chore then becomes running the dog on a daily basis. Of course, people who let their dogs run free in a rural setting don't need to put them on leashes and run along with them. But most people live in areas where leashes are necessary. So let your dog serve as your personal trainer.

By Randall Parker    2010 January 11 08:01 PM   Entry Permalink | Comments (0)
2010 January 05 Tuesday
Exercise Slows Telomere Decay?

Researchers in Germany find that endurance training slows the decay of the telomere caps on chromosomes, suggesting that exercise can slow the aging process.

Researchers focused on telomeres, the protective caps on the chromosomes that keep a cell's DNA stable but shorten with age.

They found telomeres shortened less quickly in key immune cells of athletes with a long history of endurance training.

The study, by Saarland University, appears in the journal Circulation.

A previous study found the converse: Sedentary Lifestyles Age Chromosome Telomeres Faster. Telomere length has been linked to rate of aging in many studies. Also see my previous posts "Telomere Length Indicates Mortality Risk" and "Chronic Stress Accelerates Aging As Measured By Telomere Length" and New Telomere Lengthening Technique Developed and Telomeres Wear Down Quicker In Men Than Women and Aged Blood Stem Cells Indicator For Cardiovascular Disease Risk.

By Randall Parker    2010 January 05 12:22 AM   Entry Permalink | Comments (0)
2009 December 20 Sunday
Dogs Better Than Human Walking Companions

No surprise here. Oh, and cats aren't getting you any exercise.

Is it better to walk a human or to walk a dog?

New research from the University of Missouri has found that people who walk dogs are more consistent about regular exercise and show more improvement in fitness than people who walk with a human companion. In a 12-week study of 54 older adults at an assisted living home, 35 people were assigned to a walking program for five days a week, while the remaining 19 served as a control group. Among the walkers, 23 selected a friend or spouse to serve as a regular walking partner along a trail laid out near the home. Another 12 participants took a bus daily to a local animal shelter where they were assigned a dog to walk.

Click thru to read the details. Suffice to say, dogs rule.

Speaking as someone whose late, great, and much missed Australian Shepherd served as my personal trainer this result comes as no surprise. You walk in the door after work and that dog knows what you should do next. Get your ass in gear and lets start running up the road to a park. Been home for a few hours continuously? Time for another work-out. Come on. Can't you see how important this is?

Friends are just going to take turns flaking out on each other. Dogs just love that exercise far too much and can't imagine how something else could possibly be more important. Dogs are good for humans.

By Randall Parker    2009 December 20 12:01 PM   Entry Permalink | Comments (17)
2009 November 02 Monday
Low Exercise Not Cause Of Adolescent Obesity Spike?

This result strengthens my suspicion that high fructose corn syrup is to blame for the obesity epidemic.

Decreased physical activity may have little to do with the recent spike in obesity rates among U.S. adolescents, according to researchers at the Johns Hopkins Bloomberg School of Public Health. Prompted by growing concern that the increase was due to decreased physical activity associated with increased TV viewing time and other sedentary behaviors, researchers examined the patterns and time trends in physical activity and sedentary behaviors among U.S. adolescents based on nationally representative data collected since 1991. The review found signs indicating that the physical activity among adolescents increased while TV viewing decreased in recent years. The results are featured in the October 30 online issue of Obesity Reviews.

"Although only one third of U.S. adolescents met the recommended levels of physical activity, there is no clear evidence they had become less active over the past decade while the prevalence of obesity continued to rise," said Youfa Wang, MD, PhD, MS, senior author of the study and an associate professor with the Bloomberg School's Center for Human Nutrition and the Department of International Health. "During the recent decade, U.S. adolescents had greater access to TV, but significantly fewer of them watched TV for three or more hours per day. In addition, daily physical education attendance rates improved along with the use of physical education class in engaging in physical activity. However, there are considerable differences in the patterns by age, sex and ethnicity."

If less exercise isn't the cause of the obesity epidemic then what is? Some people say it is cheaper food. I'm skeptical. Lots of middle class kids had all the food they could eat in the 1960s. Refrigerators were full. Why did the obesity epidemic come later?

By Randall Parker    2009 November 02 10:20 PM   Entry Permalink | Comments (11)
2009 September 29 Tuesday
Dogs Better Exercise Companions Than Humans

The University of Missouri College of Veterinary Medicine Research Center for Human-Animal Interaction (ReCHAI) finds dogs do a better job of getting older adults out for exercise.

ReCHAI sponsors several projects that attempt to further the understanding and value of the relationship between humans and animals. In 2008, ReCHAI sponsored the “Walk a Hound, Lose a Pound and Stay Fit for Seniors.” In the preliminary program, a group of older adults were matched with shelter dogs, while another group of older adults were partnered with a human walk buddy. For 12 weeks, participants were encouraged to walk on an outdoor trail for one hour, five times a week. At the end of the program, researchers measured how much the older adults’ activity levels improved.

“The older people who walked their dogs improved their walking capabilities by 28 percent,” Johnson said. “They had more confidence walking on the trail, and they increased their speed. The older people who walked with humans only had a 4 percent increase in their walking capabilities. The human walking buddies tended to discourage each other and used excuses such as the weather being too hot.”

This bit about humans discouraging each other contrasts with my own experience with dog walking. They are not interested in excuses. They want to go galloping up the road. They think exercise is just plain great. A good dog is a great professional trainer.

By Randall Parker    2009 September 29 12:04 AM   Entry Permalink | Comments (3)
2009 June 28 Sunday
Exercise Boosts Neural Stem Cells In Aged Mice

Get yourself a running wheel and start running like a mouse. Aged mice exercising on a running wheel get more stem cells in their brains as a result.

In research published in Stem Cells, Dr Daniel Blackmore and his colleagues at the Queensland Brain Institute (QBI) have shown that moderate exercise directly increases the number of stem cells in the ageing brain.

Stem cells and new neuron generation decline with age. So anything that reverses or slows this trend might slow brain aging.

However, it has also been known for more than a decade that the number of new neurons we produce slowly declines with age.

According to QBI neuroscientist Dr Blackmore, researchers are interested in finding ways to stimulate the production of neurons to negate any decline brought about by age or disease.

"Our findings suggest that moderate exercise, from early to late in life, can have a very positive effect," Dr Blackmore said.

Some people look for pills to take to slow or reverse aging. But you should first get the low tech basics right. Eat more fruits and vegetables. Get more exercise.

By Randall Parker    2009 June 28 01:36 PM   Entry Permalink | Comments (0)
2009 May 13 Wednesday
Vitamins C, E Reduce Exercise Benefits

Quenching too many free radicals with antioxidant vitamins can increase risk of insulin-resistant diabetes.

A study published today in the "Proceedings of the National Academy of Sciences" (PNAS) suggests that vitamin C and E supplements may actually be harmful, at least in regards to diabetes risk and glucose metabolism. According to this study, the health-promoting effects of exercise require the formation of oxidative stress during sports and if this is blocked, some of these effects do not occur. In the particular study, the intake of antioxidants during a four-week exercise training class abolished the effects of exercise to improve insulin sensitivity and glucose metabolism which would help prevent diabetes, while those individuals not taking the antioxidants had major benefits in terms of metabolism from exercise.

Dr. Michael Ristow, lead-author of the study which was published by a team of researchers from Leipzig and Jena Universities (both Germany) and Harvard Medical School, points out: "Exercise causes repeated boosts of free radicals, which - according to our results - induce a health-promoting adaptive response in humans. Subsequently, our body activates molecular defense systems against stress, and metabolizes carbohydrates more efficiently, both of which prevents diabetes, and possibly other diseases. Blocking these boosts of free radicals by antioxidants accordingly blocks the health promoting effects of exercise." He further says that "short-term doses of free radicals may act like a vaccine, helping the body to defend itself from chronic stressors more efficiently by inducing a long-term adaptive response".

Dr. C. Ronald Kahn, a collaborating author from the Joslin Diabetes Center and Harvard Medical School, noted: "This is a very important study for the millions of people at risk for type 2 diabetes. Exercise is a proven way to improve insulin action and reduce diabetes risk, but clearly this beneficial effect can be largely blocked by taking these very commonly used vitamin supplements. We need larger studies to fully assess this effect, but in the meantime, individuals at risk for diabetes and maybe even some with type 2 diabetes itself, need to think carefully about the use of these vitamin supplements, especially if they exercise regularly to improve there health."

This result isn't surprising because free radicals work as signaling agents in the body. Denman Harman, the guy who originally proposed the free radical theory of aging back around 1955, said if you take too much antioxidant vitamins you will feel slugging because you'll basically damp down your metabolism. That was his own personal experience (as related in an interview I can no longer find on the web btw).

So use of antioxidant vitamins brings trade-offs. How to figure out optimal doses? The doses used in this study are in line with what a lot of people take.

For the study, Ristow and colleagues observed two groups of young men during four weeks of intensive exercise training. One group took a combination of vitamin C (1000 mg/day) and vitamin E (400 IU/day) while the other did not.

The men who took the supplements showed no changes in their levels of ROS, whereas those who did not showed increased levels of ROS and oxidative stress.

The vitamins suppress a free radical indicator called TBARS.

Muscle biopsies showed a two-fold increase in a marker of free radicals called TBARS (thiobarbituric acid-reactive substances) in those volunteers who didn't take antioxidants, but no increase in those who did take the supplements – suggesting that they were indeed mopping them up.

What we need: a pill that will simulate the effects of exercise without causing free radical damage. Then we can sit as couch potatoes and live longer than exercisers.

By Randall Parker    2009 May 13 07:14 AM   Entry Permalink | Comments (7)
2009 March 09 Monday
Starting Exercise In Late Middle Age Works As Well

One way to spin this story is that it is never too late to improve your lifestyle and get more exercise. Another way to look at it: You can delay exercise till you hit 50.

Swedish researchers from Uppsala University monitored more than 2,200 men from the age of 50.

They found those who increased activity levels from 50 to 60 ended up living as long as those who were already exercising regularly by middle age.

There was a difference in outcomes for people who were sedentary, getting medium levels of exercise, and getting high levels at age 50. But if people stepped up from either sedentary or medium to high after age 50 they did just as well as the people who were already getting high exercise levels.

So all you people who feel smug exercising regularly in your 20s in order to live longer wipe that smug smile off your faces. Of course, the exercise will help you feel better in the now. So it still has appeal. But my guess is an excellent diet for one's full life will pay off much better than regular exercise for the same length of time.

By Randall Parker    2009 March 09 08:53 PM   Entry Permalink | Comments (7)
2008 July 31 Thursday
Scientists Put Exercise In A Pill

To supplement these drugs we are going to need pills that plant memories of a cross-country hike or perhaps memories of a river rafting trip. Two compounds make mice boost their treadmill performance. While GW1516 enhances the effects of exercise AICAR eliminates the need. Time to tune in, turn on, and drop exercise pills.

Howard Hughes Medical Institute researchers have identified two drugs that mimic many of the physiological effects of exercise. The drugs increase the ability of cells to burn fat and are the first compounds that have been shown to enhance exercise endurance.

Both drugs can be given orally and work by genetically reprogramming muscle fibers so they use energy better and can contract repeatedly without fatigue. In laboratory experiments, mice taking the drugs ran faster and longer than normal mice on treadmill tests. Animals that were given AICAR, one of the two drugs, ran 44 percent longer than untreated animals. The second compound, GW1516, had a more dramatic impact on endurance, but only when combined with exercise.

Ronald M. Evans, the Howard Hughes Medical Institute investigator who led the study, said drugs that mimic exercise could offer potent protection against obesity and related metabolic disorders. They could also help counter the effects of devastating muscle-wasting diseases like muscular dystrophy. Evans and his colleagues, who are at the Salk Institute for Biological Studies, published their findings on July 31, 2008, in an advance online publication in the journal Cell.

Concerned about the potential for abuse of the two performance-enhancing drugs, Evans has also developed a test to detect the substances in the blood and urine of athletes who may be looking for way to gain an edge on the competition.

Exercise will still be needed for the development of better coordination. But cardiovascular conditioning and muscle build-up really shouldn't take so much time out of our busy lives. Besides, why use real exercise when drugs can do a better job of making your body fit?

After four weeks of treatment with AICAR, Evans and his colleagues once again challenged sedentary mice to run on the treadmill. They found that mice that had received AICAR were able to run 44 percent longer than untreated mice. "This is a drug that is like pharmacological exercise," Evans says. "After four weeks of receiving the drug, the mice were behaving as if they'd been exercised." In fact, he says, those that got the drug actually ran longer and further than animals that received exercise training.

Read the full article if you are curious about the mechanisms of action of these drugs.

By Randall Parker    2008 July 31 10:46 PM   Entry Permalink | Comments (13)
2008 April 10 Thursday
Exercise Delays Old Age Fatigue

Exercise to prevent yourself from decaying into incapacitating fatigue.

Maintaining aerobic fitness through middle age and beyond can delay biological ageing by up to 12 years and prolong independence during old age, concludes an analysis published ahead of print in the British Journal of Sports Medicine.

Aerobic exercise, such as jogging, improves the body’s oxygen consumption and its use in generating energy (metabolism).

But maximal aerobic power starts to fall steadily from middle age, decreasing by around 5 ml/[kg.min] every decade.

When it falls below aound18 ml in men and 15 ml in women, it becomes difficult to do very much at all without severe fatigue.

In a typical sedentary man, the maximal aerobic power will have fallen to around 25 mil/[kg.min] by the age of 60, almost half of what it was at the age of 20.

But the evidence shows that regular aerobic exercise can slow or reverse the inexorable decline, even in later life.

Research shows that relatively high intensity aerobic exercise over a relatively long period boosted maximal aerobic power by 25%, equivalent to a gain of 6 ml/ [kg.min], or 10 to 12 biological years.

By Randall Parker    2008 April 10 11:06 PM   Entry Permalink | Comments (2)
2008 February 06 Wednesday
Electronic Reminders More Than Double Exercise

Stanford researchers find that electronic hand held Personal Digital Assistants (PDAs) that periodically remind people to exercise more than double the amount of exercise that people engage in.

The researchers invited the public to participate in this new study through local mass-media outlets, like the Palo Alto Daily News and the San Jose Mercury News. Out of 69 callers who were screened for eligibility, 37 were invited to be study participants and randomly assigned to an eight-week program in which they either received a Dell Axim X5 PDA, or traditional handouts related to physical activity.

"Then we let 'em roll," King said.

While Hollywood stars use personal trainers to accomplish similar goals a far cheaper PDA works very well. A human personal trainer could call you several times a day to achieve the same goal. Or an automated phone calling service could do the same thing. But that'd get annoying. Text messaging would be less intrusive.

The Dell Axim X5, chosen for its large-sized, easy-to-read screen and good contrast, was fitted with a program that asked participants approximately three minutes' worth of questions. Among the questions: Where are you now" Who are you with" What barriers did you face in doing your physical activity routine" The device automatically beeped once in the afternoon and once in the evening; if participants ignored it the first time, it beeped three additional times at 30-minute intervals. During the second (evening) session, the device also asked participants about their goals for the next day.

With this program, participants could set goals, track their physical activity progress twice a day and get feedback on how well they were meeting their goals. After eight weeks, the researchers found that while participants assigned to the PDA group devoted approximately five hours each week to exercise, those in the control group spent only about two hours on physical activities-in other words, the PDA users were more than twice as active.

One surprise was the participants' positive response to the program's persistence. The PDA users liked the three additional "reminder" beeps that went off if they failed to respond to the first one. In fact, almost half of them wound up responding to the PDA only after being beeped for the fourth time.

"The PDAs can really keep on you," King observed with wry humor. "We were surprised by that; we thought by the time they heard the fourth beep, they might find it annoying and not respond at all."

The researchers want to use cell phones next.

Wait until PDAs include sensors and include the ability to read sensors embedded in your body. Then they'll be able to tell you when you are becoming too fatigued, sleep deprived, hungry, or angry. A PDA will become a full life coach. Add in a wireless link to an artificial intelligence running somewhere on a server and the PDA could remind you of all manner of things you ought to do or not do and say or not say.

By Randall Parker    2008 February 06 10:04 PM   Entry Permalink | Comments (0)
2008 January 28 Monday
Sedentary Lifestyles Age Chromosome Telomeres Faster

Telomere caps on chromosomes shrink more quickly in people who do not get much exercise.

Individuals who are physically active during their leisure time appear to be biologically younger than those with sedentary lifestyles, according to a report in the January 28 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Regular exercisers have lower rates of cardiovascular disease, type 2 diabetes, cancer, high blood pressure, obesity and osteoporosis, according to background information in the article. “A sedentary lifestyle increases the propensity to aging-related disease and premature death,” the authors write. “Inactivity may diminish life expectancy not only by predisposing to aging-related diseases but also because it may influence the aging process itself.”

Lynn F. Cherkas, Ph.D., of King’s College London, and colleagues studied 2,401 white twins, administering questionnaires on physical activity level, smoking habits and socioeconomic status. The participants also provided a blood sample from which DNA was extracted. The researchers examined the length of telomeres—repeated sequences at the end of chromosomes—in the twins’ white blood cells (leukocytes). Leukocyte telomeres progressively shorten over time and may serve as a marker of biological age.

We are losing 21 nucleotides (DNA letters) per year off the ends of our chromosomes. I miss my fallen nucleotides.

Telomere length decreased with age, with an average loss of 21 nucleotides (structural units) per year. Men and women who were less physically active in their leisure time had shorter leukocyte telomeres than those who were more active. “Such a relationship between leukocyte telomere length and physical activity level remained significant after adjustment for body mass index, smoking, socioeconomic status and physical activity at work,” the authors write. “The mean difference in leukocyte telomere length between the most active [who performed an average of 199 minutes of physical activity per week] and least active [16 minutes of physical activity per week] subjects was 200 nucleotides, which means that the most active subjects had telomeres the same length as sedentary individuals up to 10 years younger, on average.” A sub-analysis comparing pairs in which twins had different levels of physical activity showed similar results.

199 minutes of physical activity per week: Can you manage that? Thats almost 20 minutes per day.

Of course there are caveats to keep in mind when thinking about a study like this one. Are less healthy people less able to exercise? Do they have less energy to exercise? Which way does the direction of causation flow? Also, does shorter telomere length really indicate shorter life expectancy? Still, there's a strong chance that this study's most obvious interpretation is correct: exercise slows aging.

I'm inclined toward believing the most obvious interpretation because of other work done on telomeres and aging. Toward that end see some of my other posts on telomere lengths and aging: Chronic Stress Accelerates Aging As Measured By Telomere Length, Telomere Length Indicates Mortality Risk, Telomeres Shorten Quicker If You Have Less Vitamin D, and Telomere Shortening Linked To Osteoarthritis.

By Randall Parker    2008 January 28 08:03 PM   Entry Permalink | Comments (4)
2007 November 23 Friday
Pedometers With Goals Up Exercise And Lower Weight

Get a pedometer to measure your walking and adopt a goal.

Dena M. Bravata, M.D., M.S., of Stanford University, Calif., and colleagues evaluated the association between pedometer use and physical activity and health outcomes among adults. The authors searched databases for studies and articles on this topic, and identified 26 studies with a total of 2,767 participants that met inclusion criteria (eight randomized controlled trials [RCTs] and 18 observational studies). The participants’ average age was 49 years and 85 percent were women. The average intervention duration was 18 weeks.

In the RCTs, pedometer users significantly increased their physical activity by 2,491 steps per day more than control participants. Among the observational studies, pedometer users significantly increased their physical activity by 2,183 steps per day over baseline (2,000 steps is about one mile). Overall, pedometer users increased their physical activity by 26.9 percent over baseline. Among the intervention characteristics, having a step goal was the key predictor of increased physical activity. The three studies that did not include a step goal had no significant improvement in physical activity with pedometer use in contrast to increases of more than 2,000 steps per day with the use of a 10,000-step-per-day goal or other goal.

Intervention participants significantly decreased their body mass index by 0.38 from baseline. This reduction was associated with older age and having a step goal. Participants also significantly decreased their systolic blood pressure by 3.8 mm Hg, which was associated with greater systolic blood pressure at baseline and change in steps per day.

Use technology to give you immediate feedback in progress toward goals. Makes sense.

I'm thinking I ought to get a pedometer.Go for the the pocket Omron HJ-720ITC or the corded Omron HJ-112? Does the pocket one work as well?

By Randall Parker    2007 November 23 03:53 PM   Entry Permalink | Comments (2)
2007 November 10 Saturday
Exercise Pleasure Compounds Protect Heart

When you exercise and get an endorphin high the chemicals that cause that high are what deliver the heart benefits of exercise.

Endorphins and other morphine-like substances known as opioids, which are released during exercise, don't just make you feel good -- they may also protect you from heart attacks, according to University of Iowa researchers.

...

The UI study investigated the idea that the opioids produced by exercise might have a direct role in cardio-protection. The researchers compared rats that exercised with rats that did not. As expected, exercised rats sustained significantly less heart damage from a heart attack than non-exercised rats. The researchers then showed that blocking opioid receptors completely eliminated these cardio-protective effects in exercising rats, suggesting that opioids are responsible for some of the cardiac benefits of exercise.

This result raises the possibility that some day an opioid/endorphin injection or pill might deliver the benefits to your heart that you currently have to get by hard and time-consuming exercise. Time for your exercise injection.

When you can get all the health benefits of exercising without exercising will you still exercise? (assuming that you exercise now)

By Randall Parker    2007 November 10 08:43 PM   Entry Permalink | Comments (2)
2007 October 30 Tuesday
Vibrated Mice Form More Bone And Less Fat

Science sometimes turns up weird results. Clinton T. Rubin has discovered that placing mice on vibrating plates for short periods of time strengthens bones and decreases fat.

Dr. Rubin, director of the Center for Biotechnology at the State University of New York at Stony Brook, is reporting that in mice, a simple treatment that does not involve drugs appears to be directing cells to turn into bone instead of fat.

All he does is put mice on a platform that buzzes at such a low frequency that some people cannot even feel it. The mice stand there for 15 minutes a day, five days a week. Afterward, they have 27 percent less fat than mice that did not stand on the platform — and correspondingly more bone.

Bone marrow accumulates fat as we age. Should we sit in vibrating plates a few times a week to maintain bone health and reduce fat? This could become the next weight loss rage.

Rubin has spent years investigating why bones decay with age and found that more intense impacts don't appear to be the biggest cause of increases in bone strength. This led him in the direction of looking at low frequency vibrations.

Over the years, he and his colleagues discovered that high-magnitude signals, like the ones created by the impact as foot hits pavement, were not the predominant signals affecting bone. Instead, bone responded to signals that were high in frequency but low in magnitude, more like a buzzing than a pounding.

That makes sense, he went on, because muscles quiver when they contract, and that quivering is the predominant signal to bones. It occurs when people stand still, for example, and their muscles contract to keep them upright. As people age, they lose many of those postural muscles, making them less able to balance, more apt to fall and, perhaps, prone to loss of bone.

Rubin suspects that the vibrations send signals to stem cells to tell them to become bone cells rather than fat cells.

The US National Institutes of Health are sufficiently intrigued to fund a large study to see if this effect works on elderly people.

If this can work in humans the optimal frequency and intensity might take some work to discover. Some frequencies and intensities might even cause harm. So think twice before you start constructing your own vibrating plate for weight loss.

I'm reminded of those electric vibrator belt machines where people lean into the belt which is connected to an electric motor on a pedestal. The sellers of those machines are derided as con artists selling junk. But maybe those machines provide some real benefit?

I also wonder whether operating machinery that vibrates your body (e.g. tillers, jack hammers, saws, even some ride mowers and motorcycles) might help keep bones strong and fat off.

By Randall Parker    2007 October 30 08:40 PM   Entry Permalink | Comments (7)
2007 October 16 Tuesday
Cycling Worse Than Running For Bones

Bicycling is not the way to slow down declines in bone mineral density.

The researchers measured bone mineral density in 43 competitive male cyclists and runners ages 20 to 59. Findings of the study included:

  • The cyclists had significantly lower bone mineral density of the whole body, especially of the lumbar spine, compared to runners.
  • 63 percent of the cyclists had osteopenia of the spine or hip compared with 19 percent of the runners.
  • Cyclists were seven-times more likely to have osteopenia of the spine than the runners.

Get out there and pound some pavement.

By Randall Parker    2007 October 16 05:44 PM   Entry Permalink | Comments (3)
2007 September 28 Friday
Exercise Slows Joint Aging?

Moderate exercise appears to reduce the risk of developing osteoarthritis.

For a clearer picture of the impact of physical activity on the knee joint, a team of researchers in Australia turned to magnetic resonance imaging (MRI). This highly accurate high-tech tool makes it possible to directly visualize joint structures, detect early and pre-disease states of OA, and assess the influence of potential risk factors. Taking advantage of this novel methodology, the researchers studied the effect of physical activity, in various degrees of intensity, frequency, and duration, on knee structures in a total of 257 healthy adults between the ages of 50 and 79, with no history of knee injury or OA. Their findings, presented in the October 2007 issue of Arthritis Care & Research, suggest that exercise that is good for the heart is also good for the knee.

Obviously the exercise an NFL quarterback gets while getting slammed into by an offensive lineman isn't covered by this study. Those guys do real damage to each other and live to suffer the results the rest of their lives.

Exercise that gets the heart pumping builds up cartilage volume in joints.

Among the notable findings, both baseline and current vigorous physical activity— exercise that gets the heart pumping and the body sweating—were associated with an increase in tibial cartilage volume, free from cartilage defects. What’s more, tibial cartilage volume increased with frequency and duration of vigorous activity. Recent weight-bearing exercise was also linked to increased tibial cartilage volume and reduced cartilage defects. Finally, moderate physical activity, including regular walking, was associated with a lower incidence of bone marrow lesions.

So exercise probably reduces the risk of bone fractures as well.

Sweat it up at least 20 minutes per week.

“Our data suggest that at least 20 minutes once per week of activity sufficient to result in sweating or some shortness of breath might be adequate. This is similar to, if not somewhat less than, the recommendations for cardiovascular health,” Dr. Cicuttini observes.

You already ought to be getting as much or more exercise for your heart anyway.

By Randall Parker    2007 September 28 08:04 AM   Entry Permalink | Comments (0)
2007 May 28 Monday
Exercise Partially Restores Aged Muscle Gene Profiles

A research report published in Plos One (open source - you can read it) finds that 6 months of resistance training exercise changes gene expression patterns in aged muscle to look more like youthful muscle.

Human aging is associated with skeletal muscle atrophy and functional impairment (sarcopenia). Multiple lines of evidence suggest that mitochondrial dysfunction is a major contributor to sarcopenia. We evaluated whether healthy aging was associated with a transcriptional profile reflecting mitochondrial impairment and whether resistance exercise could reverse this signature to that approximating a younger physiological age. Skeletal muscle biopsies from healthy older (N = 25) and younger (N = 26) adult men and women were compared using gene expression profiling, and a subset of these were related to measurements of muscle strength. 14 of the older adults had muscle samples taken before and after a six-month resistance exercise-training program. Before exercise training, older adults were 59% weaker than younger, but after six months of training in older adults, strength improved significantly (P<0.001) such that they were only 38% lower than young adults. As a consequence of age, we found 596 genes differentially expressed using a false discovery rate cut-off of 5%. Prior to the exercise training, the transcriptome profile showed a dramatic enrichment of genes associated with mitochondrial function with age. However, following exercise training the transcriptional signature of aging was markedly reversed back to that of younger levels for most genes that were affected by both age and exercise. We conclude that healthy older adults show evidence of mitochondrial impairment and muscle weakness, but that this can be partially reversed at the phenotypic level, and substantially reversed at the transcriptome level, following six months of resistance exercise training.

The reversal isn't complete. Aged muscles are still weaker and their gene expression patterns are still different than youthful patterns.

We need to know why the aged muscles do not fully regain youthful strength when exercised. Perhaps losses of muscle cells through cell death leaves too few muscle cells to regain youthful strength. Or maybe limitations in aged vasculature prevents enough oxygen and nutrients from getting through.

The resistance training exercise does not simply substitute for a lower level of exercise in the elderly. Younger control subjects who did not exercise much had youthful gene expression profiles even though they didn't exercise much.

It is possible that our observation of a reversal of the mitochondrial based aging signatures could indicate that the response to exercise training was solely due to lower habitual exercise in the older adults. Arguing against this is the fact that the current study was specifically designed to avoid this confounder by selecting healthy, active, disease-free older adults and comparing them to similarly active younger adults (relatively inactive for age). In the future, it will be important to determine whether long-term or life-long exercise in humans can attenuate the transcriptome signature of aging using cross-sectional sampling in Masters athletes.

We need a gene therapy delivery mechanism that can deliver replacement mitochondrial DNA (mtDNA) into muscle tissues. Such a therapy would help us answer the question of whether accumulated mtDNA damage is a substantial cause of muscle aging. I hope the answer is "yes" because methods to replace mtDNA will be much easier to develop than methods to replace nuclear DNA (i.e. the DNA in chromosomes in the nucleus of cells). Why the difference in difficulty? The nucleus contains over 2.9 billion base pairs of DNA whereas the mtDNA contains about 15,000 base pairs. So development of methods to deliver replacement mtDNA should be a relatively simpler task.

By Randall Parker    2007 May 28 10:43 PM   Entry Permalink | Comments (1)
2007 May 05 Saturday
Exercise Slows Weight Gain With Age

If you don't mind running 30 miles per week for years on end you can slow your weight gain.

The study, conducted by Paul Williams of the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), followed 6,119 men and 2,221 women who maintained their weekly running mileage (to within three miles per week) over a seven-year period. On average, the men and women who ran over 30 miles per week gained half the weight of those who ran less than 15 miles per week.

"To my knowledge, this is the only study of its type," says Williams, a staff scientist in Berkeley Lab's Life Sciences Division. "Other studies have tracked exercise over time, but the majority of people will have changed their exercise habits considerably."

The research is the latest report from the National Runners' Health Study, a 20-year research initiative started by Williams that includes more than 120,000 runners. It appears in the May 3 issue of the journal Medicine and Science in Sports and Exercise.

Guys, even if you run more than 30 miles a week (not gonna do it) you'll still gain more than half a pound annually. Over 40 years that adds up to 32 pounds. Ugh.

Specifically, between the time subjects entered the study and when they were re-contacted seven years later, 25-to-34-year-old men gained 1.4 pounds annually if they ran less than 15 miles per week. In addition, male runners gained 0.8 pounds annually if they ran between 15 and 30 miles per week, and 0.6 pounds annually if they ran more than 30 miles per week.

Is there a level of exercise at which people do not gain weight as they age? If so, what is that level?

Women who ran more than 30 miles a week gained more weight than men who did.

This trend is mirrored in women. Women between the ages of 18 and 25 gained about two pounds annually if they ran less than 15 miles per week, 1.4 pounds annually if they ran 15 to 30 miles per week, and slightly more than three-quarters of a pound annually if they ran more than 30 miles per week. Other benefits to running more miles each week included fewer inches gained around the waist in both men and women, and fewer added inches to the hips in women.

A chart on calories burned in various forms of exercise (also see here and here) suggests these joggers are burning up perhaps 100-120 calories per mile (the possible range is larger depending on weight and other factors). So the 30 mile per week runners might be burning 3000 calories per week or 150,000 calories per year. They burn about 150,000 calories to keep off maybe a pound per year? Maybe only 1% or 2% of the additional calories burned translate into a reduction in fat accumulation. Note I'm doing really rough calculations ignoring body size and other factors. We'd need to see numbers on weight gain of non-runners to make an exact calculation. But the amount of calories one needs to burn is pretty large if the goal is weight control.

The calories burnt running are only part of the story though. The runners probably have more muscle than non-exercisers. So they burn more calories when they are sitting still (muscles use energy even when not doing work). The exercise must increase their appetites almost as much as it increases their calorie burning.

Do the Amish farmers gain weight as they grow old? Or do any other higher exercise groups keep off the weight as they grow older?

Update: Is there some way using less exercise to shift the body into a state where it is less likely to accumulate fat? Maybe. Short high intensity interval training increases the amount of fat burnt in all exercise.

Researchers at McMaster University in Hamilton, Ontario, had the exercisers sprint for 30 seconds, then either stop or pedal gently for four minutes.

Such a stark improvement in endurance after 15 minutes of intense cycling spread over two weeks was all the more surprising because the volunteers were already reasonably fit. They jogged, biked or did aerobic exercise two to three times a week.

Doing bursts of hard exercise not only improves cardiovascular fitness but also the body’s ability to burn fat, even during low- or moderate-intensity workouts, according to a study published this month, also in the Journal of Applied Physiology. Eight women in their early 20s cycled for 10 sets of four minutes of hard riding, followed by two minutes of rest. Over two weeks, they completed seven interval workouts.

After interval training, the amount of fat burned in an hour of continuous moderate cycling increased by 36 percent, said Jason L. Talanian, the lead author of the study and an exercise scientist at the University of Guelph in Ontario. Cardiovascular fitness — the ability of the heart and lungs to supply oxygen to working muscles — improved by 13 percent.

But this research is too small in scale and in time interval to tell us anything about the long term effects of high intensity exercise for short periods of time. Will such a pattern of exercise reduce weight gain with age?

Update II: If exercise seems like too much trouble consumption of soy might turn up your metabolism and reduce weight.

To compare soy peptides with leptin, de Mejia’s graduate student Nerissa Vaughn, with the help of associate professor Lee Beverly, implanted cannulas in the brains of lab rats; they then injected leptin as a positive control. When the scientists could see their model was working, they injected two formulations of hydrolyzed soy protein and soy peptides so the scientists could monitor the effects of each on food intake and weight loss.

Injections were given three times a week for two weeks; during that time, the animals had unlimited access to food and water. Food intake was measured 3, 6, 12, 24, and 48 hours after injection, and the rats were weighed 24 and 48 hours after injection. All rats received the same amount of exercise, and all rats lost weight.

But, after the third injection, de Mejia and Vaughn noticed a significant weight loss in the group of animals that had received one of the soy hydrolysates, even though the animals hadn’t changed their eating habits. In this instance, soy protein appeared to have caused weight loss not by reducing food intake but by altering the rats’ metabolism.

The experiment not only showed that soy peptides could interact with receptors in the brain, it also demonstrated that eating less isn’t always the reason for weight loss, the researcher said.

While these scientists used injection the press release claims that other research has shown that increased soy consumption is correlated with reduced weight. I've not read that claim before. Does that ring a bell with anyone else? If you are familiar with that research please post a comment.

Update III: A friend who suffers from arthritis says that the long term costs of joint wear from running have to be considered when deciding how to keep off the weight. Many of those who already have bad knees, hips and backs can't go running 30 miles a week without suffering intense pain. But what about the younger ones with still good joints? Do they put themselves at greater risk of knee and hip arthritis if they run 30 miles a week?

Stem cell therapies to replenish aging joint stem cells will some day allow people to avoid osteoarthritis and other joint problems that come with age. If we already had the needed cell therapies then the long term advantage of running would be clearer cut. But in the mean time aerobic exercise in ways that reduce joint impact (e.g. swimming and perhaps exercise cycles?) might make more sense as a way to get the exercise with less wear and tear on the joints.

By Randall Parker    2007 May 05 06:17 PM   Entry Permalink | Comments (15)
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