Short bouts of intense exercise can help women lose weight

Even brief episodes of physical activity that exceed a certain level of intensity can have as positive an effect on weight, U.S. researchers say. Jessie X. Fan, professor of family and consumer studies at the University of Utah, and colleagues said current physical activity guideline for U.S. adults is to get at least 150 minutes of moderate to vigorous physical activity a week, which can be accumulated in eight to 10 minute periods at a time. Moderate to vigorous physical activity is defined as greater than 2,020 counts per minute measured with an accelerometer -- a device that measures proper acceleration. For an average person in an everyday setting without a fancy gadget to gauge the exertion, that would translate roughly to a walking speed of about 3 mph. But taking the stairs, parking at the far end of the lot, and walking to the store or between errands are choices that can add up and can make a positive health difference, Fan said. The study, published in the American Journal of Health Promotion, found higher-intensity activity was associated with a lower risk of obesity, whether in "bouts" of fewer or greater than 10 minutes. "What we learned is that for preventing weight gain, the intensity of the activity matters more than duration," Fan said in a statement. "This new understanding is important because fewer than 5 percent of U.S. adults today achieve the recommended level of physical activity in a week according to the current physical activity guidelines. Knowing that even short bouts of 'brisk' activity can add up to a positive effect is an encouraging message for promoting better health." The study showed for women, each daily minute spent in higher-intensity short bouts was related to a decrease of .07 body mass index. This means that when comparing two women each 5-feet, 5-inches tall, the woman who regularly added a minute of brisk activity to her day weighed nearly a half-pound less. Each daily minute of higher-intensity activity lowered the odds of obesity -- 5 percent for women, and 2 percent for men, the study said.