Regular exercise throughout adulthood may protect our muscles against age-related loss and damage later, according to an interesting new study of lifelong athletes and their thighs. The study finds that active older men’s muscles resemble, at a cellular level, those of 25-year-olds and weather inflammatory damage much better than the muscles of sedentary older people.

The study also raises some cautionary questions about whether waiting until middle age or later to start exercising might prove to be challenging for the lifelong health of our muscles.

Physical aging is a complicated and enigmatic process, as any of us who are living and experiencing it know. Precipitated by little-understood changes in the workings of our cells and physiological systems, it proceeds in stuttering fits and starts, affecting some people and body parts earlier or more noticeably than others.

Muscles are among the body parts most vulnerable to time. Almost all of us begin losing some muscle mass and strength by early middle age, with the process accelerating as the decades pass. While the full causes for this decline remain unknown, most aging researchers agree that a subtle, age-related rise in inflammation throughout our bodies plays a role.