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After 10 minutes of exercise, hour-long boost

WASHINGTON — Ten minutes of brisk exercise triggers metabolic changes that last at least an hour. The unfair news for panting newbies: The more fit you are, the more benefits you just might be getting.

We all know that exercise and a good diet are important for health, protecting against heart disease and diabetes, among other conditions. But what exactly causes the health improvement from working up a sweat or from eating, say, more olive oil than saturated fat? And are some people biologically predisposed to get more benefit than others?

They're among questions that metabolic profiling, a new field called metabolomics, aims to answer in hopes of one day optimizing those benefits — or finding patterns that may signal risk for disease and new ways to treat it.

"We're only beginning to catalog the metabolic variability between people," says Dr. Robert Gerszten of Massachusetts General Hospital, whose team just took a step toward that goal.

The researchers measured biochemical changes in the blood of a variety of people: the healthy middle-aged, some who became short of breath with exertion, and marathon runners.

First, in 70 healthy people put on a treadmill, the team found more than 20 metabolites that change during exercise, naturally produced compounds involved in burning calories and fat and improving blood-sugar control. Some weren't known until now to be involved with exercise. Some revved up during exercise, like those involved in processing fat. Others involved with cellular stress decreased with exercise.

Those are pretty wonky findings, a first step in a complex field. But they back today's health advice that even brief bouts of activity are good.