10 minutes of exercise, hour-long effects

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Study: 10 minutes of exercise, hour-long effects

Jun 1, 3:04 AM (ET)

By LAURAN NEERGAARD

WASHINGTON (AP) - 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. 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.

" Ten minutes of exercise has at least an hour of effects on your body, "

says Gerszten, who found some of the metabolic changes that began after

10 minutes on the treadmill still were measurable 60 minutes after

people cooled down.

Your heart rate rapidly drops back to normal when you quit moving,

usually in 10 minutes or so. So finding lingering biochemical changes

offers what Gerszten calls " tantalizing evidence " of how exercise may be

building up longer-term benefits.

Back to the blood. Thinner people had greater increases in a metabolite

named niacinamide, a nutrient byproduct that's involved in blood-sugar

control, the team from Mass General and the Broad Institute of MIT and

Harvard reported last week in the journal Science Translational

Medicine.

Checking a metabolite of fat breakdown, the team found people who were

more fit - as measured by oxygen intake during exercise - appeared to be

burning more fat than the less fit, or than people with shortness of

breath, a possible symptom of heart disease.

The extremely fit - 25 Boston Marathon runners - had ten-fold increases

in that metabolite after the race. Still other differences in

metabolites allowed the researchers to tell which runners had finished

in under four hours and which weren't as speedy.

" We have a chemical snapshot of what the more fit person looks like. Now

we have to see if making someone's metabolism look like that snapshot,

whether or not that's going to improve their performance, " says

Gerszten, whose ultimate goal is better cardiac care.

Don't expect a pill ever to substitute for a workout - the new work

shows how complicated the body's response to exercise is, says

metabolomics researcher Dr. Debbie Muoio of Duke University Medical

Center.

But scientists are hunting nutritional compounds that might help tweak

metabolic processes in specific ways. For example, Muoio discovered the

muscles of diabetic animals lack enough of a metabolite named carnitine,

and that feeding them more improved their control of blood sugar. Now,

Muoio is beginning a pilot study in 25 older adults with pre-diabetes to

see if carnitine supplements might work similarly in people who lack

enough.

Next up: With University of Vermont researchers, she's testing how

metabolic changes correlate with health measures in a study of people

who alternate between a carefully controlled Mediterranean diet and

higher-fat diets.

" The longterm hope is you could use this in making our way toward

personalized medicine, " Muoio says.

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EDITOR's NOTE - n Neergaard covers health and medical issues for

The Associated Press in Washington.

http://apnews.excite.com/article/20100601/D9G2B1UO0.html