Also OP, aren't you 19-20 ? No need to be worried, and certainly no need for BP machines. If you've not been exercising like this for long, then yes you will suffer after. I was doing long club rides from 16, and got battered at first. My son, being 19, can suddenly fly past me on a climb, but he runs out of 'puff' quite quickly (and he is T1) and his bloods run low. He hasn't got 'pacing' - I've told him 'this climb takes 20 minutes at my pace', whe will go fast then be knackered within a couple of minutes. It's experience. He doesn't ride often, and is a bean pole.