Not a surgeon, so can't speak to the surgical lifestyle, but I know of many.

I started road biking as MSII, but had to give it up because I couldn't maintain the time commitment, but that was also because I had a bunch of other stuff going on. Without knowing more about that other activities you are into, it's hard to answer your question. But as a ballpark, during my MSIII and MSIV years, I've been able to do at least commit to 3-4hours/week (for weekdays) and 3-4 hours/week (on weekends) for ECs (sports, music, etc..) and still have some time to socialize and study. My surg rotations were the hardest because of long days. During my surg rotations, I had 3 days a week that were at least 6am-6pm and bedtime for me was 930ish. During those days, I was lucky to get a 30min run in on those days. Weekends were better if I wasn't on call.

Residency is much better. I've been able to get 5-6 hours/week (for weekdays) and 3-4 hours/week (on weekends) for ECs. My surg colleagues tend to get quite busy as they get more senior as they're trying to maximize their OR time. I think like most things though, if it's important to you, you'll make time for it.