Comment by k__

I did it that way.

I was a couch potato until 30 or so.

Then I stopped using public transport and biked everywhere. I lived on a hill, so every time I got back I had to get back up again.

After a few years, I added swimming, because it cools you in the summer. Full body excercise and you don't even notice the sweat.

Later, I added lifting. Got me a home gym and went 2-3 times a week. Not having to leave the house for a dedicated workout really helped.