I gave up my moderate road cycling practice when I was diagnosed with osteopenia to focus more on weight bearing exercise, including lots of hiking. 7 years later I've crossed into osteoporosis. The other day I rode a bit while on vacation and was shocked at how winded I was. I'm planning on including more cycling in my exercise mix to keep up on cardiovascular health. Cycling isn't great for bones but does a great job with that. Just got a great Black Friday deal on an indoor exercise bike.