How much exercise is too much?

There doesn't appear to be any studies on the longevity of marathon or triathlon runners,

but this study in which more than a thousand joggers were followed for up to a dozen years

is able to offer some insight. Surprisingly, the light joggers were followed for up to a dozen years, is able to offer some insight.

Surprisingly, the light joggers appeared to have the lowest mortality rates.

Moderate joggers had a worse mortality rate than light joggers.

They still did better than that of sedentary non-joggers, but strenuous joggers did not. There wasn't a significant difference in death rates between those jogging more

than four hours a week and those not jogging at all.

So the death versus jogging intensity graph was a U-shaped curve

with the lowest mortality bottoming out among those taking it relatively easy,

clocking 1 to 2.4 hours a week over

no more than three days at a slower average pace.

So more may not necessarily be better.

The jogging study spurred sensationalist headlines like fast running can kill, but the

strenuous joggers were just dying at a higher rate compared

to light joggers, not compared to the general population of non-joggers. Here's what a

meta-analysis found of all such similar studies. Yes, diminishing returns, but the only clear

mortality bump was associated with inactivity. However, there was a retrospective analysis of more than a thousand male Olympic

track and field athletes that suggested that those who had extraordinary early peak performance

had lifespans shortened by almost five years.

The regimen for peak performance may not be the same as that for optimum health and longevity.

Perhaps the mantra, exercise is medicine metaphor, should be taken a step further,

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