The minimum daily requirement of exercise to prevent weight gain is 30 minutes a day of walking, or 12 miles a week of walking or running. A study of sedentary, overweight men and women (aged 40-65 years) showed they lost body fat and weight when they walked or ran 12 miles a week during an 8-month study, without changing their diet. A control group of non-exercisers all gained weight and fat during the 8-month study.
Get Your Minimum Daily Requirement of Walking"From the perspective of prevention, it appears that the 30 minutes per day will keep most people from gaining the additional weight associated with inactivity," said said Cris Slentz, Ph.D of the Duke University research team in a news release.
"Given the increase in obesity in the U.S., it would seem likely that many in our society may have fallen below this minimal level of physical activity required to maintain body weight."
More Exercise and Higher Intensity Even BetterThe group that exercised at 65-80% of maximum heart rate (equivalent of running or racewalking) for 20 miles a week saw even better results than those who either ran for 12 miles a week or walked for 12 miles a week. This shows that more is better.
Walking 30 minutes a day or 12 miles a week at 40-55% maximum heart rate: Lost 1% of body weight, lost 1.6% of waist measurement, lost 2% of body fat and gained 0.7% lean muscle.
Jogging at 65-80% of maximum heart rate for 12 miles a week: lost 1% of body weight, lost 1.4% of waist measurement, lost 2.6% of body fat, gained 1.4% lean muscle.
Jogging at 65-80% of maximum heart rate for 20 miles a week: lost 3.5% of body weight, lost 3.4% of waist measurement, lost 4.9% of body fat, gained 1.4% lean muscle.
Non-exercise control group: Gained 1.1% weight, gained 0.8% waist measurement, gained 0.5% body fat.
Exercise Without Dieting Reduces Health RisksThe study shows the effects of exercise without dieting in maintaining body weight and reducing risk of major illness. "This study revealed a clear dose-response effect between the amount of exercise and decreases in measurements of central obesity and total body fat mass, reversing the effects seen in the inactive group," Slentz said. "The close relationship between central body fat and cardiovascular disease, diabetes and hypertension lends further importance to this finding."
The Duke study was published in the Jan. 12, 2004 "Archives of Internal Medicine." The study was supported by a $4.3 million grant from the National Heart, Lung and Blood Institute. The trial, dubbed STRRIDE (Studies of Targeted Risk Reduction Interventions through Defined Exercise), was led by Duke cardiologist William Kraus, M.D.
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Cris A. Slentz, Brian D. Duscha, et.al. "Effects of the Amount of Exercise on Body Weight, Body Composition, and Measures of Central Obesity," Archives of Internal Medcine 2004;164:31-39.