Longevity & AgingPhysical Decline Starts Before 40 — A 47-Year Population Study Confirms the Timeline
The SPAF cohort followed 427 Swedes (48% women) born in 1958 from age 16 to 63, objectively measuring aerobic capacity, muscular endurance, and leg power across five time points. Aerobic capacity and muscular endurance peaked between ages 26–36, while leg power peaked even earlier (age 19 in women, 27 in men). Decline began slowly at 0.3–0.6% per year but accelerated to 2.0–2.5% per year by the early 60s, with total losses of 30–48% from peak. Critically, this trajectory mirrored data from elite athletes, confirming that physical decline in the general population begins well before sarcopenia is clinically diagnosed. Higher physical activity levels and university education were linked to better performance throughout life.
