I feel like I'm also pretty fit and healthy (Garmin VO2max estimate today was 69 today, ftp test last week was 348, resting HR 38), but it does not feel healthy to hit my max HR. About the only time I hit my max HR is during a triathlon right after I transition from the bike to the run, and I start getting all sorts of wonky symptoms. I can hold 175 bpm for an hour, but as soon I get up around 195 and 200 my body tells me to get out of there.