Determining Max Heart Rate

Hi Scott & Steve –

First off, have to say fantastic work on Training for the New Alpinism and this site. Both are top-notch resources, and the fact that you’re willing to dedicate time answering questions on this forum in addition to your regular work speaks volumes about the kind of folks you both are. It’s much appreciated!

I’ve tried twice now to determine my max heart rate using a treadmill and heart rate monitor, and I feel like I’m missing something and not getting to a max cardiac response. Quick background in case it’s helpful — I’m a 28-year-old male who’s been active my whole life and spent the last 4 years focusing on running ultra marathons, up to 100 milers. So I would imagine I’m fairly aerobically fit, but by no means elite.

The max heart rate I got on the two tests was 180 and 176, respectively. On the first test I was perhaps not fully rested and chalked the lower-than-expected result up to that. The second test I was fully rested but I think I tried to ramp up the effort too quickly after warming up and fatigued my muscles faster than the heart/lungs could catch up. I don’t know — how much can botching the test in these ways affect the result? Could I be 5 beats per minute off? 10?

Based on rule-of-thumb general formulas I would predict my max heart rate should be somewhere around 185 – 192. I’ve also found my aerobic threshold at 160 beats per minute, which would be unrealistically high (89%!) if my max heart rate was only 180. After experimenting with this a couple times on the treadmill I do feel confident that 160 beats per minute is my true aerobic threshold, yet this seems too high; it would be 84% of a 190 max, for instance.

So, either my 160 beats per minute aerobic threshold is a much higher percentage of my max heart rate than I would expect based on my previous training, or it’s an incorrect result, or I truly haven’t been able to elicit a max cardiac response — or all of the above. Thanks everyone for any and all help.