I experimented with MAF and similar “Low Zone” training (the UphillAthlete methodology) for several years until about 18 months ago when I switched over to 8020 and regular/weekly intensity sessions. By “Low Zone” I mean exclusive endurance training in Zone 1 heartrates, to the point I had a upper threshold limiter I would stay under “no matter what.” When I did MAF this was my the standard MAF formula, but UphillAthlete has the same methodology but is more scientific in determining the upper limit of Zone 1 with aerobic threshold testing.
Anyway, a couple of things I have noticed since I left those Low Zone styles behind.
1) I can tolerate “race effort” much better. It seemed like a shock to the system when I would race previously, and it makes sense, I was never exposed to that effort in training so of course it was a shock. This also extends to any upper-zone intensity – repeats, tempo work, all of that is more tolerable when I do it regularly.
2) The reason I am posting though is because I also notice what I am calling “HR Volatility” now. This means I notice that my HR bpm is much more likely to make BIG jumps and drops over the course of a workout. Previously it would stay in a narrow range (not just because I was capping the upper limit for HR) and the aforementioned massive efforts would be needed to get HR into some of those upper zones.
I try not stay so laser focused on HR anymore, instead focusing on RPE or at least on power/pace zones instead but I can’t help but notice this huge range of volatility when analyzing workouts after the fact. Is this a known thing? Is it good? I know HR Variability is a good thing in general but this is obviously not the same thing. Just curious if any of our coaches here have any thoughts, thanks in advance.