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.
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.
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.
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?
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)
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.
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:
Get out there and pound some pavement.
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.
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.
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?
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.