At 72, it amazes me how cycling alone has kept me healthy and flexible. No weights, no stretching, no supplements or medication, no other physical activity to speak of, other than a bit of occasional walking: nothing but cycling.

Having retired 2 years ago, I spend something like 2 to 3 hours or a bit more a day six days a week on the bike, and, as my GP told me the last time I went in for a checkup, about 5 years ago, I'm healthier than 99.999% of people my age.

It's partly genetic, of course, and partly that I've never smoked or taken drugs and have stayed thin throughout my life, but I'm convinced that regular cycling at a reasonably effortful level has an all but miraculous effect on health.

It's possible that as time passes, I'll pay for being too lazy to work with resistance/weights, of course. if so, studies seem to indicate that starting late in life can still be beneficial.

The issue of whether stretching is a good idea seems to have become controversial, though, with results of some studies having indicated that connective tissue can become weakened. So my laziness there has paid off, maybe.