The Right Dose of Exercise for a Longer Life
Joyce Park stashed this in Fitness
Two very large studies of middle-aged people have concluded that the optimal amount of exercise for longer life is... 450 minutes per week (just over an hour per day) of walking, of which just over 30% should be "strenuous".
And anything more than that has diminishing returns except for the fact that you enjoy it.
The returns are diminishing, but still significant. The hint from a recent small study that too much exercise could be bad was refuted by these much larger studies.
"At that point, the benefits plateaued, the researchers found, but they never significantly declined. Those few individuals engaging in 10 times or more the recommended exercise dose gained about the same reduction in mortality risk as people who simply met the guidelines. They did not gain significantly more health bang for all of those additional hours spent sweating. But they also did not increase their risk of dying young.
The other new study of exercise and mortality reached a somewhat similar conclusion about intensity. While a few recent studies have intimated that frequent, strenuous exercise might contribute to early mortality, the new study found the reverse."
I think if they continue to track these people into older age, they'll find both quality of life and mortality to be even more different between each level. The other study found more benefit with more exercise:
"Then, as with the other study, they checked death statistics. And as in the other study, they found that meeting the exercise guidelines substantially reduced the risk of early death, even if someone’s exercise was moderate, such as walking.
But if someone engaged in even occasional vigorous exercise, he or she gained a small but not unimportant additional reduction in mortality. Those who spent up to 30 percent of their weekly exercise time in vigorous activities were 9 percent less likely to die prematurely than people who exercised for the same amount of time but always moderately, while those who spent more than 30 percent of their exercise time in strenuous activities gained an extra 13 percent reduction in early mortality, compared with people who never broke much of a sweat. The researchers did not note any increase in mortality, even among those few people completing the largest amounts of intense exercise."
It's clear there's a trade off.
Some people really enjoy fitness activities so for them the extra time is well spent.
Other people don't have extra time and want to know where the sweet spot is.
I don't know why they don't give you graphs of this stuff! Compared to totally sedentary people, the benefits were:
20% less risk of mortality if you exercise up to 150 minutes a week (the recommended minimum)
31% less risk at 150 - 300 minutes a week
37% at 300 - 450 minutes a week
39% at 450 - 750 minutes a week
So the cost-benefit to that final 300 minutes was quite weak. Suck it, triathletes!
At least one of those studies were only for 14 years. 2% less risk for mortality in middle age over just 14 years is still significant. Extrapolate that out over the last 40-50 years, probably with accelerating curves, and it may be a lot larger than you think. But 450 minutes is starting to be a lot of time, 64 minutes a day. Using another 7 hours per week may not be offset by extra life.
Don't get me wrong, I exercise a lot because I enjoy it :) But as a public health issue I don't like a "more is better" approach, especially when the data gets so weak towards the top of the scale. 450 is plenty to recommend... we'd be a totally different nation if every American walked that much.