…so I dust off the road bike and start getting out on that again.
Did you retest AnT and AeT? Weight-bearing heart rates are usually higher than non-, especially if you haven’t been cycling in a while. (Trained cyclists may have them closer.)
Training Peaks talk about building quite a lot of 75-80% MHR intervals into your weekly program…
MHR? Do you have a link to those recommendations? Training Peaks metrics are built on the work of Andrew Coggan who works from AnT (i.e. “threshold”, “lactate threshold”, “FTP”, etc). By heart rate, he recommends that most volume be <= 83% of AnT HR; for cycling, <= 75% AnT power.
Then I read above which talks about adding a lot of easy sessions of 65% – 80% MHR which again takes me well above AeT.
No, 65-80% of AeT HR if the aerobic gap is less than 10%. At 100% AeT for those suffering from ADS. (Watch your denominators.)
Am I ruining my aerobic base for short term gains by adding in these harder sessions?
It’s hard to tell until we can nail down the actual intensity. I would do threshold tests for cycling first, and then revisit the TP prescription you mentioned and confirm what the benchmark intensity is (MHR, AnT HR, etc).