presta
Legendary Member
If you don't know what the OPs MHR is, that's all the more reason not to make wild assumptions and push your luck. There's no harm in starting easy and building up, there most definitely is harm in going at it like a bull in a china shop. How long did it take you to get to a position where you can sustain 90% for that long? It's not something you can jump off the couch and do straight off. Nicole Cooke's program waits 8 weeks before introducing that sort of intensity, and then only for a couple of minutes at a time. I ended up where I am because I listened to too many people like you.Sorry, but that is mostly nonsense, not least because you don't know what the OPs max HR is, it could be 200.
Secondly I can hold 90% of my max for over an hour, so clearly that's a short burst.
General advice for those new to exercise is to take it easy and build up. And if worried speak to a professional.
Everyone is physiologically different, so giving advice using assumptions based on flawed general principles is not great.
I appreciate that you may have had medical issues in the past, but that doesn't mean that your experience is universal.
What you can do after 10 years is not what a beginner can realistically expect to do if he's just got up of the couch. This sort of stuff is likely to make people think a) there's something wrong, and b) they're not exercising hard enough, when neither is necessarily the case.I'm in my 50's, I've been cycling seriously for about 10 years.......I can maintain a high heart-rate for quite a while, over 85% of my maximum for 3 hours for instance.