Key points from article :
A decades-long study from Sweden suggests that human physical ability peaks earlier than many people expect—around the age of 35—before beginning a gradual decline. Researchers at the Karolinska Institutet tracked the fitness and strength of more than 400 randomly selected men and women born in 1958, following them for 47 years from adolescence (age 16) into later adulthood (age 63). The findings were published in the Journal of Cachexia, Sarcopenia and Muscle, with Maria Westerståhl as the lead author.
The study shows that fitness and strength start to decrease from the mid-30s, regardless of how much people train. At first, this decline is slow, but it accelerates with age. By 63, participants had lost between 30% and 48% of their peak physical capacity. Importantly, the pattern was similar in men and women, and mirrors trends previously observed in elite athletes, suggesting this is a general feature of human ageing rather than a result of lifestyle alone.
Despite this early decline, the researchers stress that it is never too late to benefit from exercise. Participants who became physically active in adulthood still improved their physical capacity by 5–10%. While physical activity cannot fully stop age-related decline, it can significantly slow it, helping to preserve strength and independence later in life. The team plans to continue following the participants into their late 60s to better understand how lifestyle, health, and biology interact to shape physical ageing.
