From the mailbag: What is the ideal HR zone for the bike & run portion of a full IM for someone just hoping to finish? I was thinking it is high Z2 and low Z3. Also, what is the BPM difference between bike and run LT HR zones?Answer:
Cardiac DriftWhen an athlete takes on a new training regimen or has not been training as much, they will experience cardiac drift at first. This is when the effort stays the same, yet the HR rises. I will allow myself to let this happen once per week when I am starting up my training again, but typically I back right down and stay within my HR parameters. Once you have a solid endurance base, you shouldn’t see much in the way of cardiac drift unless you are dehydrated, and that is pretty normal.
Optimal Training Zones
While training for an Ironman race, most of our training should be done in Zone 2. [.....]