Swedish study reveals physical decline begins around age 35

A 47-year longitudinal study conducted by scientists at the Karolinska Institute in Sweden has found that physical performance and strength begin to decline around the age of 35, even in individuals maintaining an active lifestyle.

Part of the Swedish Physical Activity and Fitness (SPAF) study, the research tracked 427 men and women born in 1958 from age 16 to 63. The findings, published in the Journal of Cachexia, Sarcopenia and Muscle, indicate that aerobic capacity and muscular endurance typically peak between the ages of 26 and 36.

By age 63, average performance in measured parameters—including aerobic capacity, muscular endurance, and muscular strength—had decreased by approximately 30% to 48% compared to peak levels. However, researchers noted that regular exercise can significantly slow this decline, and improving physical fitness remains possible even at older ages.