Thursday, December 23, 2010

Exercise 6hrs/wk for 20 years. Still gain weight. :(


I guess the good news is that you gained less weight. The bad news is if your motivation for exercising was weight loss, your 20 years of exercise not only didn't help you lose weight but your weight gain was only marginally less than your couch potato friends.

What am I talking about?

A study published last week in the Journal of the American Medical Association which using data from the CARDIA trial, sought to examine the relationship between exercise and weight gain over a 20 year period.

3,554 young adult participants were followed through to middle age. At baseline and years 2, 5, 7, 10, 15 and 20, their physical activity was measured by means of the CARDIA Physical Activity History questionnaire which scored, you guessed it, physical activity. Subjects were also weighed and had their heights and waist circumferences measured at all visits. Dietary intake was examined at baseline and years 7 and 20 by means of a food frequency questionnaire.

The results?

After controlling for age, race, baseline BMI, education, smoking status and alcohol use, habitual high activity was associated with smaller increases in weight and waist circumferences. Men who exercised a minimum of 5 hours a week gained 5.7 fewer pounds, and had 1.22 inches smaller waists than men exercising less than 90 minutes a week. Women who exercised a minimum of 5 hours a week gained 13.42 fewer pounds (though women as a percentile gained more weight than men in total) and had 1.54 inches smaller waists than women exercising less than 90 minutes a week.

Put another way, exercise 1hr/day, 6 days a week and if you're a man you'll gain 4.5 fewer ounces a year than if you exercised less than 15mins/day. If you're a woman you'll gain 11 fewer ounces.

But you'll still gain.

Put another way - it ain't about exercise.

If you want to manage your weight, you've got to manage your intake.

Of course if you want to stay healthy, you've got to exercise. No one said life was fair, so exercise to improve your cardiovascular health, reduce your risk of diabetes, improve glycemic control, increase your mobility, increase your endurance, extend your life and provide you with functional independence.

But please, please don't make the mistake of honouring your New Year's weight loss resolution by exercising like stink and not changing your diet because in a best case scenario it would seem that all you'll end up doing is gaining less in 2011 and likely quitting an incredibly beneficial and healthful behaviour because it didn't lead you to dramatic weight loss results.

Hankinson, A., Daviglus, M., Bouchard, C., Carnethon, M., Lewis, C., Schreiner, P., Liu, K., & Sidney, S. (2010). Maintaining a High Physical Activity Level Over 20 Years and Weight Gain JAMA: The Journal of the American Medical Association, 304 (23), 2603-2610 DOI: 10.1001/jama.2010.1843

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18 comments:

  1. In the physical activity questionnaire, was physical activity understood to be intentional exercise, or did it also take into account general changes in overall daily activity levels? As people get older and perhaps more settled, most are likely to buy cars, etc. that decrease their overall amount of daily activity, which could then work against the effects of intentional exercise. Is this controlled for?

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  2. Hi Calantha,

    I don't think they did, though studies on daily energy expenditure using doubly labeled water suggest that DEE doesn't change, hasn't changed since the 1980s and is the same as would be seen in third world nations.

    If you want to explore the CARDIA physical activity questionnaire you can have a peek at the paper that validated its use:

    Jacobs DR, Hahn LP, Haskell WL, Pirie P, Sidney S. Validity and reliability of short physical activity history: CARDIA and the Minnesota Heart Health Program. J Cardiopulm Rehabil. 1989;9:448-459
    doi:10.1097/00008483-198911000-00003.

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  3. Gaining some weight over years is a normal physiological process called ageing! In fact maintaining fitness muscle mass and weight over decennies need more and more effort, from both intake and expenditure

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  4. Of course Paul.

    Though the point of the article and the commentary was to highlight the fact that while statistically significant, practically speaking, there was virtually no difference in the age related weight gain of individuals exercising an hour or more a day and those exercising 15 minutes or less per day.

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  5. The secret to weight loss and weight maintenance is: Eat Right, Be Active and Repeat.

    As a Weight Watchers Leader I see so many members that do one or the other well but cheat themselves as you must do both in order to lose and even maintain.

    Thanks again Yoni!

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  6. The study results are interesting, but as with everything I do to maintain or improve my health, exercise isn't just about weight gain/loss for me. Regular exercise provides so many benefits to my health that go far beyond the number on the scale, so even if this study showed no difference whatsoever to the weight of someone who exercises and someone who doesn't, I would still exercise.

    (P.S. If I seem a bit grumpy, it is because I'm nursing three injuries and am not able to exercise to the extent that I like to...which affects my mood)

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  7. Makes sense to me. As I've ramped up my marathon training, I also want to lose a little weight. Even running 40+ miles per week, I don't really lose weight unless I make a real effort to control my food intake.

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  8. Put another way, (my pro point of view)
    I would be happy to be a regularly exercising 45 y old woman and weighing 13 lbs less than women who have not been exercising during the last 20y (50% of the population)or to be a 45 y-old man and weigh 6 pounds less that those who don't exercise. It is a good news for demonstrating how important is exercise for weight gain prevention.

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  9. I love you Paul, you are the glass half full king of exercise and weight loss.

    Me?

    I would bet my bottom dollar that the health and quality of life of those exercising 6hrs/wk for 20 years were leaps and bounds better than their sedentary counterparts and that should make all of those exercisers very happy.

    Unfortunately most people see exercise as a vehicle for weight management and unlike you most people will not be happy about spending 312 hours a year exercising in order to gain 4.5 ounces less a year than their sedentary friends.

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  10. It doesn't even have to be crazy high-intensity exercise either. Just simply walking for me is so enjoyable and in 30 minutes, I feel a slight rejuvenation (maybe from better circulation or something) that lasts throughout the day. If I don't walk, I feel pretty crummy (tired, achy). I did the exercise to lose weight thing for 3 years at one point and I was yo-yo'ing pretty bad. I did group exercise classes at Goodlife 5-6 days a week, sometimes 2 classes in a row. I was not watching what I was eating and did not understand why I was going up and down so much. My hunger would increase/decrease depending on how much exercise I did (i.e. yoga class vs. body attack class). I thought I could make changes in my diet and it worked for a bit, but then I would make a different change and I'd gain again. This is why I NEED to journal, count calories, and measure stuff. My memory is aweful and my estimation is worse.

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  11. Anonymous10:30 am

    Of course the best type method of weight management is the combination of physical activity AND nutritional management.

    I can't help but be skeptical of studies that use self reported food journals and physical activity journals as evidence of anything.

    I don't know what anyone elses experience is, but mine is that patients under report food intake and over report physical activity.

    I can't help but wonder if this happened in this study as well.

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  12. Anonymous @ 10:30AM, I understand your point when speaking about individuals involved in a study, but just to clarify, the journalling I'm referring to is to keep track for myself, so that when I do gain weight, I will know why so that I can make the necessary adjustments.

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  13. The #1 myth about weight loss:

    Eat Less, Exercise More

    Unfortunately, most experts espouse it and most people buy into it. It doesn't work.

    The good news ... you can eat more and when it comes to exercise, you had a good post that demonstrates why exercise alone doesn't cut it.

    Resolve to Live a Healthier Lifestyle: http://bit.ly/hfbYlp

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  14. Anonymous12:22 pm

    Question 1:

    What about exercise to build muscle and counteract the tendency of people to lose muscle, not just fat, when they diet to lose weight.

    I don't mean exercise to burn calories (you can eat WAY more than you can burn off) -
    what about strength, weight lifting, muscle building exercises.

    That's supposed to help you lose weight because muscle burns more calories than fat even at rest.

    Is muscle-building exercise insignificant in losing weight? Is muscle-building just as useless as calorie-burning exercise? Or is that just another myth?


    Question 2:

    Those people weighed at the end of the study ... was there a body composition analysis ... eg if there were 2 similar people, the exerciser weighed only a couple of lbs less than the non-exerciser, what was the total amount of FAT on each person.

    Maybe the exercisers were SMALLER because a larger portion of their body was muscle, even if their weight was practically the same.

    Totally apart from the health issues, people want to lose weight to look better, younger, and have nicer looking clothes. An insignificant difference in weight might hide a big difference in appearance because of the body being more lean and muscular, as well as being more agile and energetic.

    If the study didn't look at body composition and appearance, it misses the reason many people try to lose weight - to look better - so the insignificant weight difference might miss a very significant appearance difference.

    For this, as well as health, people might value exercise to get looking good, even if they don't lose a lot of weight.

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  15. Yoni,
    with your glass half empty and my glass half full, we make a good balance. And congratulation to the 10 to 25% of the ppulation who exercise daily to claim all the benefits of exercise. Fo the others, be very carefull about what you eat, every day, any time. Good luck!

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  16. I think the myth is that people can build large amounts of muscle and sustain them.

    Most people are cyclical exercisers. To build and sustain muscle you've can't stop. Stop going to the gym and kiss the muscle goodbye.

    Regarding body composition, their measure of waist circumference might be thought of as a means, in a sense, to determine whether or not there were many fewer inches on the hard core exercisers and as I noted, men's waists were 1.22 inches smaller and women's 1.54 inches smaller. Certainly not nothing from a medical perspective, but likely not enough from a personal one for most.

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  17. Another thing people don't realize is that muscle doesn't burn as much calories at rest as you would think.

    This is coming from a muscled up olympic lifter, who eats a boat load, but has to constantly cycle his diet because the fat piles up

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  18. Exercising for health is a great idea, however exercising to lose weight (and to keep the weight off) ends in failure 99% of the time.

    Look at Eddie Izzard. He ran 43 marathons in 51 days and lost no weight.

    The problem with doing any exercise (for weight loss) is it gives you a voracious appetite - thereby (unless you have fantastic willpower and ignore your body's screams for more nutrients) you will have to compensate by eating extra food.

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