Most people think of exercise as a weight loss strategy. But, weight is about 50% genetically determined and, in some cases, exercising might even cause you to gain weight. Muscle weighs more than fat, so as you get stronger, your weight might go up rather than down. Also, the body’s metabolic system slows down to conserve energy as we burn more calories through exercise. If we only exercise to lose weight, then people who are slim genetically might think they don’t need to bother, and heavy people are left discouraged.
Because weight and fitness are commonly correlated, it can be hard to separate our understanding of these issues. You might not realize that very heavy people can be fit. This fall, for example, as you cheer for your favorite football team, pay more attention to the impressive examples of obese players with remarkable cardiovascular fitness and strength.
The study results graphed below clarify this issue. Mortality rates for people over 60 are sorted by weight and fitness. The blue bars are the normal weight participants and the green bars are the obese participants. You can see that the sedentary participants (bars to the right) are dying at a much higher rate than the fit participants (bars on the left). The fit participants, whether of normal weight or obese, are living longer. Interestingly, the highest mortality levels are for sedentary people of normal weight. This might be because, as we get older, being too thin is associated with frailty, which is a health risk factor.
Studies like this one have led to the conclusion that “sitting is the new smoking.” In fact, most of what we think of as age-related decline is actually caused by sedentary lifestyle. Your cardiovascular health (especially as measured by your VO2 max) is a much better predictor of mortality and general health than the number of pounds your scale shows. Rather than focusing so much on how many pounds we weigh, let’s bring our attention to how many fun ways we can find to move all of our pounds. Exercise for your health, quality of life and enjoyable longevity.