Peak Fitness and the Slow March of Aging

A Swedish 47-year longitudinal study followed 427 people from age 16 to 63, showing muscular power peaks around age 19 in women and 27 in men, aerobic capacity peaks in the mid-30s, and a gradual decline of about 1% per year that speeds up with age. Individual aging paths vary greatly, but regular, varied physical activity is the best defense against decline; the study’s limitations include only five data points over 47 years and binary exercise data, yet it’s clear: it’s never too late to start exercising to maintain fitness.