Effects of physical activity intensity, frequency, and activity type on 10-y weight change in middle-aged men and women.

BACKGROUND: Increased physical activity is often recommended for weight maintenance and loss.
OBJECTIVE: To examine how intensity, frequency, and type of recreational physical activity are associated with weight gain attenuation over a 10-y period. PARTICIPANTS: Over 15 000 adults between 53 and 57 y living in western Washington State recruited between 2000 and 2002. MEASUREMENTS: Self-reported measures of physical activity (using a questionnaire), height, and weight.
METHODS: We examined associations between physical activity and weight change after age 45 y. All analyses controlled for age at baseline, weight at age 45 y (continuous), diet, education, smoking, and weight change between ages 30 and 45 y, and were stratified by sex and body mass index (BMI) at age 45 y (normal weight, overweight, or obese).
RESULTS: Increasing MET-hours and sessions per week of high-, moderate- and low-intensity activities over 10 y were inversely related to weight gain after age 45 y. Generally, associations were stronger for women than for men and for obese compared to normal weight or overweight individuals. Obese women and men who participated in 75-100 min per week of fast walking gained 9 and 5 pound less than nonwalkers, respectively, and lesser amounts in normal weight and overweight women and men. Jogging, aerobics, and fast cycling were associated with weight gain attenuation in most sex and age 45 y BMI groups, while slow walking, swimming, and weight lifting were not.
CONCLUSIONS: In this free-living population, long-term, regular physical activity, particularly common activities carried out at a moderate intensity such as walking, prevented some of the weight gain associated with aging.