Tsnor wrote: ↑November 6th, 2021, 12:13 am
I tried googling and was unable to find anything definitive pointing to 78% or any other number. A quick check of a medical study to see how it defined zone 1 found they were using per athlete lactate testing rather than an estimation formula which makes sense.
Net: I can't point you to where this is the average in any study. So I wish I hadn't said it was. But there is some supporting data that 78% is a reasonable number.
Yep, I think 'reasonable' is the key here. I think Seiler and others would argue that we should all stop stressing about the exact number because that number is a mirage; it is entirely dependent on the sport, on the athlete, on the duration of the workout, etc. When we all get into this literature (particularly the secondary literature which is a little loosey-goosey with their use of terminology), it seems super inconsistent and frustrating ("AAARGH! How can the same zones have different HR in different systems! What am I supposed to use?!"). But the more we all read, the more we realize that these are all just guidelines. In the same presentation you link to, Seiler actually has back-to-back graphs that show VT1/LT1 at 80% MaxHR and then 78% MaxHR in the very next slide. And then later in the same presentation he shows yet another graph where "Below VT1=68%+/-7 HRMax & Threshold = 88%+/-2 HRMax. So, clearly he isn't particularly tied to one strict definition over another (probably because different research protocols used different cutoffs). And if Stephen Seiler isn't stressed about it, then I guess I probably should be either, right?
And even if we could identify a single cutoff (say, 78%), which we can't really because it is so individual, he then reminds us that even this number wouldn't be static because it will drop the longer the workout goes (i.e., even an easy green workout can become stressful yellow if you do it long enough). It is good enough to say that the VT1/LT1 is roughly somewhere between 70-82% as a neighbourhood to go hunting for it, and then if you don't have lactate testing to help refine that range (which itself is individual and doesn't have a set # either), just fool around with different paces/watts until you can figure out what you can sustain for an hour or more without much HR drift and or you can still talk easily. That might be 78%, it might be 73%, it might be 80%. But once you've got it figured out, the good news is that it appears to be really stable even as fitness improves. So, for those of us who stress about the numbers, the best strategy is probably to just do a few weeks of easy 1 hour steady-state rows at at various paces that get us into that 70-80% range after 15-20 mins and then see if we can sustain it for another 45+ mins without much drift. Rinse-repeat. (but use a fan and open your windows!).