Every Minute Of Exercise Could Lengthen Your Life Seven Minutes

stopwatch

At a recent dinner party, a geeky friend of mine was cheerily justifying the piles of money he spends on a personal trainer. He’s feeling so great that it’s worth every cent, he exulted, “And the best part is the return on the time! Every minute you spend working out comes back to you, because you’ll live that much longer!”

“Really?” I wondered. I knew vaguely that being active lengthens life expectancy, but was the return on time spent really 1 to 1?

Certainly, I hoped it was. It’s a daily struggle to make the time to exercise, and the current federal health guidelines call for at least 150 minutes a week of moderate exercise — a lot of time that somehow manages to seem like even more, magnified by the “should” it adds to so many days. There are hundreds of other reasons to exercise, and the one that works best for me is wanting to feel at my best on that very day. But it would be very comforting, I thought, if I knew that all of that time would come back to me.

Not only do you get the time back, it comes back to you multiplied — possibly by as much as seven or eight or nine.

Let me cut to the happy conclusion: It seems that it does. And then some. If you play with the data of a recent major paper on exercise and longevity, you can calculate that not only do you get the time back; it comes back to you multiplied — possibly by as much as seven or eight or nine.

To quote Tom Anthony, a regular CommonHealth reader with a Harvard physics degree who kindly helped me with the math, “I wish I could get these paybacks in the stock market.”

This is all a bit of a public health parlor game, of course, resting on averages and approximations. You, personally, could work out ten hours a week and still die flukishly young. But the math looked so striking that I asked for a reality check from Dr. I-Min Lee of Brigham and Women’s Hospital, a Harvard professor and senior author of that recent paper, “Leisure Time Physical Activity of Moderate to Vigorous Intensity And Mortality: A Large Pooled Cohort Analysis.”

Yes, she confirmed, she had not calculated out the question before, but according to her data, a middle-aged person who gets the recommended 150 minutes per week of moderate exercise — defined as the level of brisk walking — can expect a 1-to-7 return: seven extra minutes of life gained for each minute spent exercising.

Some background: The paper on exercise and longevity broke ground by calculating for the first time the gains in life expectancy from various levels of activity. In the past, researchers had found that in general, being active gains people from two to four years of life, though some calculations concluded that it was a wash, that active people gained only as much time as they spent exercising.

(Of course, Dr. Lee noted, it’s not just how long you live, it’s how well, and exercise is key to quality of life, particularly in older age: “My mentor said it best: It’s not the years you add to your life, it’s the life you add to your years.”)

Dr. Lee’s paper drew on pooled data from six large studies that included more than 650,000 people followed over ten years, and showed that people who exercised at the recommended level gained 3.4 years of life after age 40. According to its numbers, she said:

Say you start with someone 45 years old who begins to follow the 150-minute-a-week recommendation. Average American life expectancy is 78. So: “If you start exercising at 45 and you die at 78, that means that you exercise for 33 years, at 150 minutes a week. I calculated that over 33 years you would need to spend basically 4,290 hours in exercise, which is 179 days of exercise, which is less than half a year. So that’s half a year, and you gain almost three and a half years, so it is worth exercising. That’s an approximate scenario using reasonable assumptions, and you’re getting a 1-to-7 return.”

And, I asked, what if you exercise more vigorously than the brisk-walking level?

In general, she said, more strenuous exercise has approximately double the effect. So, for example, 75 minutes of jogging has roughly the effect of 150 minutes of brisk walking. “So instead of gaining seven times the time spent, you’d be gaining 14 times.”

The curve of gain tapers off at some point.

Back-of-the-envelope math aside, many caveats are in order, including Dr. Lee’s warning that the gains do not extend infinitely. (If they did, wouldn’t we be able to live forever so long as we spent every minute exercising? Feels like a science fiction story waiting to be written.)

“Yes — if you do a little, you gain a little; if you do more, you gain more,” she said. “But the curve of gain tapers off at some point. We aren’t sure exactly at what point the risks outweigh the benefits. But this point is clearly higher than most people would do. The most common risks are musculo-skeletal injuries; we know these occur more frequently with longer duration and/or more intense physical activity.” Also, people who have long been sedentary and suddenly start exercising — like the classic snow-shovelers who keel over — run heart risks.

The message, she says, is: “If you do nothing now, just start with a little bit of exercise. If you already do a little bit, try to get the 150 minutes that are recommended. And our current recommendations say that if you’re willing to go up to 300 minutes, you do get additional benefits.”

Tom Anthony’s math came out very similar:

Computing years of life gained after age 40, running for two hours a week should gain you about four years of life. “So that is roughly 100 hours per year for your remaining 40 years or 4,000 hours in total for all 40 years. In one year, there are 24 hr/day X 365 days = 8,760 hours. So four additional years is 8,760 hr/yr X 4 yr = 35,040 hours of life gained. To gain these extra hours, you expended 4,000 hour of running. So the payback ratio is 35,040 hours gain/ 4,000 hours expended = 8.8.

Running for an hour gives you 9 hours of extra life.
Brisk walking for an hour gives you 2.9/8 X 9 = 3.2 hours of extra life.
Biking for an hour at less than 10 mph gives you 4/8 X 9 = 4.5 hours of extra life
Rope jumping for an hour gives you 10/8 X 9= 11 hours of extra life
Calisthenics for an hour gives you 8/8 X 9 = 9 extra hours of life

Here’s a bit more from the press release on Dr. Lee’s study, adding some interesting data about obesity and exercise that I’d sum up as “Better to be a bit fat and fit than normal weight but inactive”:

“We found that adding low amounts of physical activity to one’s daily routine, such as 75 minutes of brisk walking per week, was associated with increased longevity: a gain of 1.8 years of life expectancy after age 40, compared with doing no such activity,” explained I-Min Lee, MD, associate epidemiologist in the Department of Preventive Medicine at BWH and senior author on this study. “Physical activity above this minimal level was associated with additional gains in longevity. For example, walking briskly for at least 450 minutes a week was associated with a gain of 4.5 years. Further, physical activity was associated with greater longevity among persons in all BMI groups: those normal weight, overweight, and obese.”

Also:

The findings show that physical activity was associated with longer life expectancies across a range of activity levels and BMI groups. Participation in a low level of leisure time physical activity of moderate to vigorous intensity, comparable to up to 75 min of brisk walking per week, was associated with a 19 percent reduced risk of mortality compared to no such activity.

Assuming a causal relationship, which is not specifically demonstrated in this research, this level of activity would confer a 1.8 year gain in life expectancy after age 40, compared with no activity. For those who did the equivalent to 150–299 min of brisk walking per week–the basic amount of physical activity currently recommended by the federal government–the gain in life expectancy was 3.4 years. These benefits were seen in both men and women, and among white and black participants. Importantly, they were also observed among persons who were normal weight, overweight, and obese. Participants faring best were those who were both normal weight and active: among normal weight persons who were active at the level recommended by the federal government, researchers observed a gain in life expectancy of 7.2 years, compared to those with a BMI of 35 or more who did no leisure time physical activity (a 5 ft 5 in tall person with BMI of 35 weighs 210 lb).

Readers, will this help motivate you? Defensive couch potatoes who are also quantitative thinkers, do you care to challenge this math somehow? Dr. Lee’s paper is here for the full data.

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  • KELLY

    WOW!!!

    • lilly

      …………..

  • Brooklynbodybuilder

    I find that good intense exercise, clears the mind, and leaves you with a good feeling. Whether or not, it adds some years to your life, is another story. I find it helps in many ways.

  • tdubs

    I would be interesting in finding out whether the study also followed the diet habits of the participants. Typically, although not in all cases, people who are more active and physically fit also have healthier diets. Surely this also contributed to the extension of years. It would also be interesting to do a similar study but based solely on the eating habits of participants. Is it diet or exercise that helps extend our years or is it both?

  • Reasonable?

    the germaine concept here is hormesis.
    Excercise, espeically when it is short and intense provides a stressor that the body can adapt to by getting stronger…..IF sufficient time and nutrients to recover.
    To maximize hormesis requires considering the excercise stressor and the recovery.
    Nassim Taleb’s, Antifragile really highlight’s this topic.

    So

  • pat

    yeah and next week they’ll say a little chub is fine and too much ex is bad, yeah yeah–just wait the cycle out….one week wine, one week coffee, one week oh its all good, one week mediterranean, one week greek yoghurt, do this, do that.

    fact is, were all gonna die–when we’re lucky around 88.

  • http://www.facebook.com/people/David-Fragale/1205575182 David Fragale

    I’ve worked doing physical labor for thirty years, too tired to “exercise” at the end of the day. If I get hit by a bus tomorrow, all these statistics are out the window. They are irrelivent any way, as each persons medical case can be so varied. So they’re dead wrong! It’s not seven minutes, it’s ten, on im my case, with a bad heart only five. Any way, we get the idea, duh…

    • AnonymousViewer

      Hard labor isn’t exercise. (At least it isn’t in the long run.) Over time your body adapts to repetitive, strenuous work. It also accumulates injuries resulting from repetitive, strenuous activity with the same muscle groups. You may break a sweat doing your job, but your results will be different working out.

      • Anon

        Of course hard physical labor is exercise. Get off your poorly researched high horse, and stop wasting people’s time. Runners that only run are doing repetitive exercise. Using the same muscle groups. What now, that doesn’t count either? And where do you get off telling someone that does hard physical labor that they’re not exercising? I’m almost certain you went back to snacking and playing angry birds after you commented.

  • Richard Edge

    There are many ways to lengthen life. It would be more interesting, however, to see correlation between certain behaviors and the quality of the years lived. I would be happy to shave years off of the end of life, if I can be more assured of increased health and activity up to the bitter end.
    That said, I do exercise more than 300 minutes per week because I enjoy my chosen activities and for the rewards of accomplishment (read “chocolate earned”).

  • Mark Cuoccio

    People who treat exercise as a prescription will always debate the number of minutes, rate of calories, intensity, etc. Exercise, when summed this way is to unpalatable that it is no wonder few people actually indulge. Exercise “accountants” will find plausible reasons to exercise, to vegetate, or to continue debate. Have a great life, accountants. I believe exercise is a way of moving through the world; others think it’s castor oil. Take your pick.

  • Judy

    Yes, like lots of medical research, this shows a strong correlation, but it’s not a dumb correlation. It’s more than plausible, and it’s a very strong correlation. Physical exercise clearly reduces the risk of serious, potentially-fatal diseases, so it’s quite plausible that reducing the risk of these diseases would translate into extended lifespan. Some correlations are meaningless — like a hypothetical one connecting, say, eating oranges with wearing purple nail polish. But this one has meaning!

  • worldhistoryteacher

    Jim Fixx?

    • Daveman

      Jim Fixx was sedentary and a heavy smoker for years before he turned his life around through distance running. Severe atherosclerosis was likely already established. As mentioned in the article, these are population-based studies, and cannot be personalized to a single individual.

      • A Runner

        Exercise extended Jim Fixx’s life well beyond what it would have been without it. And he was the first to say that. I doubt that, given a chance, he would change any of his choices. Other, of course, than stopping and bending down in the middle of a long, fast run to tie his shoe.

  • Michael Glik

    As correlation and causality are two very different things I must point out that the research shows correlation and the article attempts to derive causality with its conclusion implying that “one minute of exercise can bring an average of seven minutes of longer life.” The article like this with its very good intention of promoting exercise brings a bad light of misconception to a serious research.

    In other words in order to make causality statement you have to have a similar group of people after 40 who exercise regularly and convince them to stop (even that is not good enough, they have to be convinced that they are exercising when they are not) in order to determine how many less years they will live compare to the group which does exercise. Such experiment would be unethical. So then one has to go to derivatives to analogy, by taking (as an example) a group of animals, establish a correlation of their life span with humans, force them change (not just observe) their
    level of physical activity and correlate to the human correlational research –
    much more work (and forcing animals do something leading to the changes of life
    expectancy can be hardly considered ethical by some of us), but without similar
    work, one cannot derive to any conclusions of causality…

    Then there is another much less serious problem, of minutes
    substitution (is one minute of reading equally valuable as a minute of
    sleeping?) and enforcement (for my 45 minutes exercise I have to go to gym,
    take a shower, fit the schedule of otherwise “productive” activities leading to
    a “loss” of 1 minute for 1 minute of exercise count in the research), but that
    much less important than the causality problem.

  • David C. Holzman

    Certainly the law of diminishing returns has to kick in somewhere. Still, the benefits are impressive. And the benefits in quality of life haven’t even been touched on.

  • Lee

    this is interesting in light of recent data the findings from which said that endurance training may actually negate and increase risk of premature death. It is hard to imagine that going from 150 minutes to 300 minutes has a doubling effect on additional years of life gained. One has to wonder at what level and at what intensity of exercise is associated with diminishing returns.