A new study appearing in the online journal Obesity claims that healthy men who did 20 minutes of daily weight training had less of an increase in age-related abdominal fat compared with men who spent the same amount of time doing aerobic activities. The study conducted by researchers and colleagues at Harvard School of Public Health says that combining weight training and aerobic activity led to the most optimal results and that aerobic exercise was associated with less weight gain compared with weight training.
While prior studies focused on a specific population, such as overweight or with type 2 diabetes, and were of a shorter duration, they had mixed results. This long-term study featured a large sample of healthy men with a wide range of body mass index. They studied the physical activity, waist circumference and body weight of 10,500 healthy U.S. men aged 40 and over that participated in the Health Professionals Follow-Up Study between 1996 and 2008.
The analysis for this study included a comparison of changes in the participants activity levels over the 12-year period to see which activities had the most affect on the mens waistlines. Those who increased the amount of time spent in weight training by 20 minutes a day had less gain in their waistline compared with men who similarly increased the amount of time they spent on moderate to vigorous aerobic exercise, and yard work or stair climbing. Those who increased their sedentary behaviors, such as TV watching, had a larger gain in their waistline.
"This study underscores the importance of weight training in reducing abdominal obesity, especially among the elderly," said Frank Hu, professor of nutrition and epidemiology at HSPH and senior author of the study. "To maintain a healthy weight and waistline, it is critical to incorporate weight training with aerobic exercise."
"Because aging is associated with sarcopenia, the loss of skeletal muscle mass, relying on body weight alone is insufficient for the study of healthy aging," added lead author Rania Mekary, a researcher in HSPH's Department of Nutrition. "Measuring waist circumference is a better indicator of healthy body composition among older adults. Engaging in resistance training or, ideally, combining it with aerobic exercise could help older adults lessen abdominal fat while increasing or preserving muscle mass."