May 05, 2007
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 bodyís 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 ó the ability of the heart and lungs to supply oxygen to working muscles ó 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 Mejiaís 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 hadnít changed their eating habits. In this instance, soy protein appeared to have caused weight loss not by reducing food intake but by altering the ratsí metabolism.

The experiment not only showed that soy peptides could interact with receptors in the brain, it also demonstrated that eating less isnít 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.

Share |      Randall Parker, 2007 May 05 06:17 PM  Aging Exercise Studies

Julian Morrison said at May 5, 2007 8:51 PM: - it seems to have the effect of causing fat calories to be burned during resting after the exercise, causing actual slimming despite burning mainly carb calories during the exercise itself.

Randall Parker said at May 5, 2007 9:21 PM:


The NY Times just published an article on high intensity interval training as well. I'm intending to update this post with an excerpt from it. But I doubt that we have a long term study of its effect on weight.

rsilvetz said at May 6, 2007 12:11 AM:

I hate to say it, and I'm going to flayed by some of the purists, but caffeine:asperin:ephedra worked just beautifully.....

Rindell said at May 6, 2007 6:57 AM:

Sorry, but you can't draw specific conclusions about your own weight gain future from this type of study. It's not valid and it's not logical to anyone who has actually trained to perform and interpret research.
As for caffeine:ASA:ephedra it works but the doses that older people need can bring bad side effects.

odograph said at May 6, 2007 7:04 AM:

I enjoy my mountain biking, and the climbs between the downhills seem to provide natural intervals.

Kurt9 said at May 6, 2007 9:33 AM:

Resistive weight training (aka body-building) is the only way to keep the weight off. Increase muscle mass increases metabolism which, in turn, reduces or prevents the build-up of fat tissue. MD's generally do not like body-building because it gives quantifiable results. This is anethema to MDs since they do not want to be judged on the basis of quantifiable metrics. Funny how MDs are like politicians and bureaucrats in the sens that they do not want accountability for what they do.

wcw said at May 6, 2007 4:05 PM:

1) 30 mi/wk is nothing. My grandparents -- who never drove -- in the old country walked into town a couple times a day, and walked around town once there. 1k in, .5k there, 1 back, x2, x7 = 22 mi/wk. They did this into their 80s.

2) the aggregate never predicts the individual. I have weighed the same amount since I was 16. It runs in my family -- I am not especially fit. Pure luck of the draw. In my late 40s, if I follow the family pattern, I will slowly gain 10k over a decade or two.

3) exercising is good for you. Who cares about your weight gain? We know it's good.

Randall Parker said at May 6, 2007 4:12 PM:


Walking is much lower impact than running and therefore wears out joints at a lower rate per mile travelled. People could do 30 miles/week walking. But it'd take much more time.

Also, if memory serves: running burns more calories per mile travelled than walking.

yael said at May 6, 2007 5:04 PM:

Brisk walking for 5-6 miles a day in MBTs, has been my most astounding success in weight control. I used to crew, row an erg machine, and at the time only my legs were "built" but I never gained any weight because of the metabalism factor- fast waliking in MBTs is pretty close to the the erg machine success but without 1/10th the intensity.

Sumyung guy said at May 7, 2007 5:45 AM:

As some of the other comments above suggest, there needs to be a study of this nature and scale on those who WALK 16-30 miles a day. In general, so long as you walk at a reasonably brisk pace, you burn about as many calories from walking a mile as you do running a mile, and as others have pointed out walking is much lower impact. Me, I could manage walking 3 miles a day, even if I'm in a job where I'd have to use a home-treadmill to do it.

For very low impact, high intensity aerobics...try swimming. It'd be interesting to see how swimming in a nice heated pool would work for folks suffering (like I do) from arthritus.

S. Cormack said at May 7, 2007 9:30 AM:

HIIT is well-established and accepted in the fitness world. There are other studies out there which examine HIIT with different intervals and durations. Right now the Body for Life regimen includes a 20-minute HIIT variant. The ones I see most frequently on the internet involve 30 second sprint - 30 second rest intervals, some use a minute instead. The goal of HIIT is to supercharge metabolism. I could see that the long-term 30 mile per week runner might not have that high a metabolism, depending on pace and whether or not their regimen included hills. If that 30 miles included intervals you might see drastically different results.

dave tweed said at May 8, 2007 1:41 AM:

Suppose, for the sake of argument, one didn't care about the aesthetics of weight gain and was interested purely the health effects. Is there any evidence doing the very large amount extremely vigorous exercise (of some sort) which does reduce weight actually correlates with good health? (One might imagine that it's resulting in a big excess of glucose "burning" products which might be deleterous/require resources to neutralise. I can't find any convincing reports either way on the web.) Note this is not about needing good muscle tone into old age: one can envisage exercise regimens which build muscle tone without burning up Randall's estimated 3000 (kilo-)calories/wk, and running certainly doesn't improve muscle tone all over the body.

cancer_man said at May 8, 2007 9:54 PM:

The thing is, we are within 10 years from stem cell therepy to heal joints and under 10 years until mzingdiet pills hit the market. All of this will look very different in 2015. Until then, jog 30-40 minutes a day if you like it, (take off a couple days a week) and walk more. It really works.

kristen said at May 29, 2007 6:10 AM:

What happens to a persons ideal weight range after they are 25 years old?

BlkMrkt said at July 11, 2008 4:09 AM:

This blurb is almost quackery. Yes, studies show interval training increases caloric consumption, but does this result in weight loss? Clearly all other factors equal, 150k calories burned for 30m/wk worth of work would account for more than 1LB of weight loss if this were the only part of the equation. I'm 42, was an elite athlete, still train heavily (50 miles per week) with intervals and weight training, but I still have gained weight over the years. On the same amount of work or less at 25 I stayed 172LBs and when on some sort of diet could dip to 168LB's. At 35 I had a setpoint of around 178 that I seemed to stay at. Now that I'm 42 I have gone up to 185 and if I diet I can get down to 179, but thats about it. My body fights me to keep itself at about 184/185. Its frustrating as it means you slow down alot with the extra weight. I am still healthy and know my knees don't hurt (that is such a crock of crap disputed by 100's of studies, its like hearing that running isn't good for women because it shakes up their insides)but wish I could stay lighter for performance.

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