It’s the whole “breathing” thing that gets to me. I’m ok for a few laps…but then I suck in water and I’m coughing and it sucks.
Ellipticals are boring as hell (watch TV), but they are also easy in the knees. And a good gym usually has lots of different kinds, to keep things less monotonous…
I alternate between aerobic and anaerobic. And I gotta get there before the throngs of undergrads in bikinis.