I’ve been following 80/20 religiously for two years and have had great results with my running. I typically run about 22 days a months and bike another 8, following the same 80/20 conventions on the bike. My HR zones are very different in the two activities as determined by Joe Friel’s 30 minute Lactate Threshold tests. The differences are very consistent across disciplines.
My runs and training rides are all very HR Zone compliant.
However, when racing my bike in a cyclocross event, as I did again last night, I stay pinned in Zone 5. In a 28 minute race, I spent 20 minutes in Z5, 5:30 in Z4 and the other three minutes in Z1-Z3.
Obviously, I am not recovering well from the bursts into Z5. My question is, should I try to keep my HR limit within Z4 for the first few laps and then max it out for the last lap? I have to think that 20+ minutes in Z5 is not a good thing and I’m probably churning away with sub-optimal efficiency. Yet… I could still do it and bested my previous time.
Obviously I need to be on the bike more frequently, build that sport-specific base, and focus on recovering from short bursts into a sustainable aerobic range. And I plan on doing this.
Again, my question is on race management. Is it best to stay in reasonable Z4 until the end, or can I just let it fly and make the best of redlining Z5?
Heart rate is not a performance metric, so if it seems to disagree with other measures of how you are performing, you should ignore it. The only thing you’d get from heeding what you think it might be telling you is slower race times.
Heart rate is highly unreliable for another of reasons, but the main one in races is sympathetic nervous system arousal, which elevates HR by up to 10 BPM above what’s normal for a given output. Even if this isn’t the main factor for you, though, I suggest you ignore your HR when racing unless you have other reasons to believe you’re pacing poorly.