So ya want PROOF?

Staying physically active is the cornerstone of counterclockwise living. To which you reply: Tell me something I don’t know.

Okay, I will.

It’s true that people like you and me who live physically active lives know the benefits we reap. And it’s true that researchers are constantly devising and conducting studies that show the extraordinary health and wellness benefits of physical activity. But it is also true that determining the precise, long-term effects of exercise is surprisingly difficult. Most large-scale exercise studies rely on questionnaires or interviews and medical records to establish the role of exercise.

But these studies, important as they are – I’ve referenced many of them on this blog and in my book — don’t actually prove that exercise causes health benefits, only that people who exercise are healthier than those who do not. To prove direct cause and effect, studies would have to be long-term, real-time, randomized, control-group trials comparing groups of physically active people with groups of sedentary folks. These kinds of studies are complicated, expensive and, even if executed flawlessly, can’t control for the volunteers’ genetics and backgrounds.

But… suppose you could study the health of identical twins, reared together in the same households, eating the same foods, learning the same habits, playing the same sports – who, in adulthood, diverged quite dramatically from one another in one respect: one twin maintained an active lifestyle; the other did not. You could, then, isolate the effects of physical activity on health because both nature (genetics) and nurture (upbringing) would be constants.

This is just what team of Finnish researchers has done.  They mined the FinnTwin database to find (male) pairs (now in their early to mid-30s) and invited them into the lab where they measured each man’s endurance, body composition and insulin sensitivity, and scanned their brains. The number of subjects studied was very small (how easy is it to find twin sets like this?), but the results were unmistakable and startling.

These genetically identical twins turned out to be very different from each other. The sedentary twin had lower endurance capacity, higher body fat percentage, and showed signs of insulin resistance. (The twins, even in adulthood, tended to have very similar diets, regardless of activity level, so food choices were unlikely to have contributed to health differences.) The active twin had significantly more gray matter than the sedentary twin, especially in areas of the brain involved in motor control and coordination.

And, to add to the gee-whiz factor: Presumably, all of these differences in the young men’s bodies and brains had developed during their few, brief years of divergent workouts. That’s how quickly exercising — or not — can affect health.

So I believe I have told you TWO things you did not know: There is a proven cause and effect link between exercise and health. And physical activity (or sedentary lifestyle) makes for significant health differences very, very quickly.

Now go out and take a spirited walk. I said: Now.