Sodium would be less of a problem if he'd get a solid 30+ minutes of heavy sweating in per day. I have to add extra sodium to my fruit drink to keep my electrolytes in decent shape, otherwise I get feeling really weird about halfway through my ride.
Back on topic, I started running on a treadmill at work when I started pushing close to 200 pounds. I hated it. I don't know how anyone can stand staring at a wall for 45 minutes. But happily I found cycling, and now have 75 to 90 minutes a day of intense aerobic exercise that I absolutely love to do.
I think one of the reasons people are so averse to cycling is that as soon as they think exercise, they think of all the times they've tried it before, and how much it SUCKED. And honestly for a lot of people, cycling is going to suck at first too because the first few weeks is NOT easy.
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Work: the 8 hours that separates bike rides.