A number of the heartrate monitors have "recovery indicators" that are based off of how steady your heartrate is I think. In other words a very solid 41.2bpm +

A number of the heartrate monitors have "recovery indicators" that are based off of how steady your heartrate is I think. In other words a very solid 41.2bpm +-0.05bpm would be indicative of full recovery and 42bpm +-2bpm means that you're still fatigued. I don't know if you've looked into that at all but I messed around with it a little some years ago and saw some correlation between low recovery scores and feeling like a ride was harder than it should have been. I say this as someone who was a competitive amateur cyclist in college during a time in grad school when I could really ride. I would also caution you against doing nothing but threshold and tempo if that's all you're doing. Morning and evening base training would be really useful and would definitely make recovery easier. I read The Cyclist's Training Bible and found that slowing down when I was supposed to go slow actually meant I went faster when I was supposed to go fast.