Attention, all you couch potatoes:

Lifespan — genetic background and physical activity

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Adulthood physical activity did not increase lifespan

Vigorous physical activity in adulthood did not increase lifespan neither in animals nor in human twins, even though physical activity is well-known to have various positive effects on health, physical fitness, and physical function. Based on both our animal and human findings, we propose that genetic factors might partly explain the frequently observed associations between high physical activity level and later reduced mortality in humans. Our finding covers vigorous physical activity started at adulthood, hence physical activity started during childhood may have different effects. Thus, it will be critical to determine whether physical activity has a positive effect on lifespan when commenced early in life.

So don’t think that the treadmill you got for Christmas is going to make you live longer.