Scientists Track Human Fitness for Nearly 50 Years and Discover When Physical Aging Really Starts

A decades-long Swedish study finds that physical decline starts around age 35, but exercise at any age still meaningfully preserves fitness. A Swedish research project spanning 47 years from Karolinska Institutet has tracked how aerobic fitness, muscular strength, and endurance shift across adult life. The findings show that physical performance can begin to decline around [...]