I just released a new web app for calculating altitude-adjusted pace! If you live at altitude and are traveling to sea level, or vice versa, it’s a super helpful tool for training and racing.
🏔️ Try my new altitude-adjusted pace calculator here!
Unlike other altitude calculators, my new altitude-adjusted pace app can explicitly account for what altitude you live and train at. So, if you live at 6,000 feet, run a 5k at 5,000 feet, and want to know what you could have run at sea level, my new web app will tell you!
The key insight behind this calculator is treating every race at a different altitude as a “natural experiment” – after factoring out the effects of things like wind, weather, and terrain, the statistical model that powers the calculator estimates the independent effect of the altitude of the race, then applies a “discount” based on what altitude the athlete lives and trains at.
That discount gets more pronounced at higher elevations: if you live and train at 3,000 feet (900 m) above sea level, acclimation to altitude does not make much of a difference. However, at 7,000 feet (2,100 m) it really matters!
One nice thing about this calculator is that the empirical results match very well with what we’d expect from the physiology of different events: longer events should be impacted more heavily, and once you get to an “aerobic saturation point”—where >95% of the event’s energy is coming from aerobic metabolism—you should see more or less a constant effect as the event gets longer.
That’s exactly what my altitude-adjusted pace calculator produces:
And you also see an increasing “badness” of altitude at particularly high elevations, which is exactly what you would expect given that the same pattern appears in scientific studies on how VO2max changes at different altitudes:
There’s clearly a worsening of the impact of altitude when you get very high up, and my altitude-adjusted calculator picks up a similar effect.
Comparing my altitude adjusted pace calculator to the NCAA track altitude conversion factors
One other interesting comparison to make is to look at my calculator’s predictions versus the now-retired NCAA conversion factors, which until recently were used in American collegiate track to convert high altitude performances to a sea-level equivalent for the purposes of determining entries into championship meets.
My calculator is pretty similar at 800m and 1500m / one mile, and differs more sharply at 3k and 5k. The 10k is somewhat closer. These NCAA factors date to the early 1980s, and (as the figure below shows) were only applied above 3,000 feet.
The differences are interesting to examine at 10k, where my model agrees with the NCAA model at very high altitudes, but differs at moderate altitudes:
As I say in the explainer to the altitude-adjusted pace calculator, even though I believe my calculator is significantly more accurate than the old NCAA conversion factors, I do not recommend using my web app for converting performances for the purpose, since a lot more goes into deciding on championship qualification criteria than merely the physiology of altitude.
🏔️ Try out my new altitude-adjusted calculator here!Â
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If you are training for the marathon (or hope to train for one soon), you should also check out my book, Marathon Excellence for Everyone. It covers how to adjust training for heat, hills, and other factors as well.
Learn more about Marathon Excellence here, or get the book now on Amazon. If you live outside of the United States, Marathon Excellence is also available in a Metric Edition with all workouts in kilometers.
I also have a shorter book from back in 2013 that covers a simple, scientifically based approach to training for distances from the 800m to the 10k, Modern Training and Physiology. Check it out if you're interested!
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