A study published in the journal Pediatrics suggests that 20 minutes of vigorous exercise a day may be the best way for teens to develop and maintain cardiorespiratory fitness.
Cardiorespiratory fitness refers to the ability of the heart and lungs to supply oxygen to the muscles and organs of the body during physical exertion. Good cardiorespiratory fitness has been shown to reduce the risk of obesity, diabetes, high blood pressure, cardiovascular disease, poor mental health, and more.
Study participants included 339 13- and 14-year-olds who participated in a two-year running-focused school exercise program, with wrist-worn trackers calculating their exercise intensity.
The researchers found that the teens maximized their cardiorespiratory fitness during a vigorous 20-minute run. Exercising for long periods of time did not improve their health. Current guidelines require teens to get at least 60 minutes of moderate-to-vigorous physical activity a day to maximize their fitness, but health and fitness experts say many teens find it difficult to maintain a daily time commitment.
According to the Centers for Disease Control and Prevention, only one in four young adults gets one hour of physical activity a day. The researchers say their findings suggest that longer periods of physical activity are not required to improve cardiorespiratory fitness when exercising vigorously rather than moderately (e.g., running rather than brisk walking). However, they noted that only cardiorespiratory fitness was assessed, and other aspects of adolescent health may benefit from lower-intensity physical activity.
This article is part of the Post’s “Big Numbers” series, which briefly covers the statistical aspects of health problems. Further information and related studies are available via hyperlinks.