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Even brief bouts of exercise can prevent weight gain, researchers show

If you're trying to keep off the pounds, get up and exercise -- even if you only have a few minutes.

Brief periods of physical activity, provided they are intense enough, can prevent weight gain just as well as the 10-minute-plus intervals that are currently recommended, according to a study published this week in the American Journal of Health Promotion.

"What we learned is that for preventing weight gain, the intensity of the activity matters more than duration," says Dr. Jessie X. Fan, professor of family and consumer studies at the University of Utah and the study leader.

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"Knowing that even short bouts of brisk activity can add up to a positive effect is an encouraging message for promoting better health," she said in a statement.

Fan said the finding was important because fewer than 5 percent of American adults get the weekly amount of exercise recommended by the Centers for Disease Control and Prevention.

The guidelines call for least 150 minutes of moderate to vigorous physical activity each week that can be accumulated in 10 minutes-spurts. Moderate to vigorous physical activity is defined roughly as walking at about three miles an hour or more formally as 2,020 counts per minute as measured by an accelerometer.

But the study showed that higher intensity activity was associated with a lower risk of obesity even if conducted in bouts of less than 10 minutes. Taking the stairs instead of an elevator, parking at the far end of a parking lot or walking to the store or between errands can add up, the researchers found.

If shorter bouts of higher intensity activity are included in Americans' weekly tallies, men exceeded the government recommendation on average with 246 minutes of exercise, the study showed. Women almost met the guideline on average with 144 minutes of exercise.

Neither men and women approached the 150-minute weekly exercise recommendation when doing workouts of eight to 10 minutes.

The study drew its participants from the National Health and Nutrition Examination Survey, which has been collecting health and nutrition data from a representative sample of adults and children in the U.S. since 1999. From 2003 to 2006, the men and women wore accelerometers for seven days, in addition to undergoing interviews.

Researchers for the study measured physical activity by length of time and intensity, and divided participants into four categories: those who engaged in higher intensity bouts of more than 10 minutes of exertion at greater than 2,020 counts per minute as measured by an accelerometer, higher intensity short bouts of less than 10 minutes, lower intensity long bouts of greater than 10 minutes of exertion but less than 2019 counts per minute and lower intensity short bouts of less than 10 minutes and less than 2019 counts per minute.

For women, each daily minute spent in higher intensity, shorter bouts offset the caloric equivalent of 0.4 pounds. If two women both 5 feet 5 inches were compared, the one who regularly added a minute of brisk activity to her day would weigh nearly a half pound less, the researchers said.

The results were similar for men.

For both, each minute of higher intensity activity lowered the odds of obesity, by 5 percent for women and 2 percent for men.

In addition to weight control, meeting physical activity guidelines could reduce risk for heart disease, Type 2 diabetes, bone fractures, some cancers and improve mental health, the CDC notes.