No kids and never worked on someone else's schedule (mid 40s). I do a lot of email and conceptional work while walking so it's technically not leisure time.
I truly admire you. I have managed to put myself on a 8km/day weekdays and 15km/day weekends schedule for last 5+ years and know how much effort is needed to do that.
I incorporated walking into my daily habits. Before I would bike, take the subway. Now I simply walk. If there is a call, I dial in with no video.