Comment by BrandoElFollito

This really depends on people and your surroundings (I mean the kind of environment you live in, including the country)

I used to play volleyball a lot at the university, and then at a business league (we were horrendous, but anyway :)). Then I travelled a lot and let myself go.

So I started to commute to the office by bike, about 15 km each way, 5 days a week for two years. I had a puncture and decided to run the remaining distance (about 2 km) because I was late. After 500 m my lungs were on fire.

55 now, I restarted this year sport to do the smallest existing triathlon. I was already biking a bit and "just" have to do the swimming and running. I am at my 10th or so run of 2.5 km (I try to do it 2 times a week) and I am dying several times on the way. The fact I make it back home is religiously miraculous.

I am not an athlete, far from this. I am not the extreme obese either. I am somewhere in between, like are most of the people I know (of different ages). I do not see them running 1 km strong (let's say right above trotting)

Ah - and I did the whole battery of medical tests to make sure that I will not literally die when training. I am in a very good shape, heart wise.