Replace aerobic exercise such as running with strength training to prevent age-related fat gain. Research shows that distance runners typically gain fat and increase waist circumference as they age. In addition, unless a runner significantly increases their weekly distance or the intensity of their running over time, they will gain fat. A simple solution to prevent this is to do strength training in addition aerobic exercise modes like running—or you can replace aerobic training altogether for better health!
A 2006 study of 12,568 regular runners found that over the 9-year study period, the majority of runners gained weight and increased waist circumference. Increases in body weight and waist circumference was greatest in men compared to women, and it was also much higher in the runners who decreased their weekly mileage over the study period. However, even runners who maintained or slightly increased mileage gained weight and had a larger waistline by the end of the study.
The only runners who didn’t get fatter were those who significantly increased their mileage during the study. For example, by tripling weekly mileage, from less than 16 km/week to more than 64 km/week, both men and women in the study decreased body weight and waist circumference significantly.
The study authors were concerned with these results since their population performed regular, fairly intense physical activity and they achieved the dose suggested by public health and fitness organizations to prevent weight gain and improve health. Cardiovascular risk factors, diabetes, and sarcopenia all increase with fat gain and the loss of lean mass that comes from regular aerobic activity.
The authors suggest that to prevent fat gain as we age it’s necessary to achieve the Institute of Medicine’s recommendation of at least 60 minutes a day of vigorous activity. They point to the need to increase the duration or intensity over time as the body adapts.
A better solution to prevent age-related fat gain is to do strength training at a vigorous intensity since it need not be done 60 minutes, 7 days a week, and the intensity can be easily modified to elicit adaptations without increasing the training time. Strength training will aid in developing muscle to prevent sarcopenia, while decreasing cardiovascular disease risk factors such as chronic inflammation and insulin resistance. At the very least, runners and people who are inclined to do aerobic exercise should do strength training as well so as to prevent age-related fat gain.
Williams, P., Wood, P. The Effects of Changing Exercise Levels on Weight and Age-Related Weight Gain. International Journal of Obesity. 2006. 30(3), 543-551.