The heart rate zone calculator on the Barbell Medicine website calculates my maximum heart rate as 164 (based on my age of 63). The calculator gives me a Zone 1 training zone of approximately 65-75% of this max heart rate and a Zone 2 training zone of approximately 75-80% of this max heart rate. The PDF accompanying the General Strength and Conditioning II Template says that Zone 1 should be 50-60% of the max heart rate and that Zone 2 should be 60-70% of the max heart rate. Is there a reason that the percentages on the calculator are different from the percentages in the PDF? Also, the calculator says that my 90% max HR is 151, but 90% of 164 is actually 148 (rounding up from 147.6).
James,
Some good questions here and a number of thoughts that are covered in the article accompanying the calculator, which is available here:
To start, there is a lot of squish in these zones and trying to convey the appropriate HR proxy for a given population is difficult. To your point, the calculator page predicts z1 to be 65-74% and Z2 to 74-81% max HR. The template uses more conservative values, as we think people using that template will generally be more trained from an lifting perspective (out of proportion to aerobic conditioning), thereby likely skewing the numbers a bit lower. Also, we include a field test that is highly recommended to dial these things in. The calculator must have been coded incorrectly to yield the wrong 90%, though this is ultimately inconsequential, given that ~ that range should be what you can sustain for about an hour. Still, it annoys me and I will have to get the developer to fix this.
Ultimately, I don’t love giving people HR zones off a predicted HR and feeling confident they’re going to be concrete without very large ranges, which makes them even less useful. I would prefer, and do recommend people do a field test to get some better data. I include information on how-to do that in the expanded PDF and brief discussion on the zones within the calculator page. If pressed, I think the HR zones are fine in the PDF for lifting-focused people who are likely buying that template, whereas the publicly available free ones are fine for less RT-focused people. If folks just wanted to use 60-80 (z1-z2), 80-90 (z3-4), and 90+ for z5, that’d be workable too, though hard to feel confident at the aerobic and anaerobic thresholds without lactate data.
Hope that helps!
-Jordan
Makes sense. Thanks.