The best time to start is twenty years ago. The second best time is now.

I just turned 50 and do calisthenics daily (over 175,000 burpees cumulatively, over 50 per day), requiring no equipment, spotter, money, or risk of injury. I have bought a few kettlebells over the years and a rowing machine.

A couple years ago I accepted a challenge by the rowing machine company, Concept2, to row at least 100,000 meters in the month between Thanksgiving and Christmas. I made it and felt great, though very tired, figuring in my late 40s I'm behind the curve.

Then I read of this 77 year old woman who rowed 100,000 meters per day for a month https://web.archive.org/web/20210306044719/https://www.row2k.... In one month she rowed more than I had in a decade.