Hi,
Just saw there’s a V02Max chart.
I am wondering how accurate is the estimation ?
The vo2-max calculated from 5m power uses the formula from this study: Five-Minute Power-Based Test to Predict Maximal Oxygen Consumption in Road Cycling in: International Journal of Sports Physiology and Performance Volume 17 Issue 1 (2021)
Since it is a calculation based exclusively on your 5-min relative power output, it will ONLY give reasonable results on workouts where you put in a true maximum 5-min effort. For that reason, it probably make the most sense to not put it in a chart and instead just refer to the 42 day high water mark shown in the Power panel.
The study looked at this sample:
Forty-six road cyclists (age 38 [9] y, height 177 [9] cm, weight 71.4 [8.6] kg, VO2max 61.13 [9.05] mL/kg/min)
The best fit linear formula they derived was this (where “relative power output” is w/kg):
VO2max = 16.6 + (8.87 * 5-min relative power output)
There is another popular formula for calculating vo2-max from 6m relative power:
VO2max = 7 + (10.8 * 6-min relative power output)
I don’t know the sample used to generate this formula.
Ignoring the difference between 5m and 6m power (mine aren’t that different at least), these two formulas coincide at approximately 5w/kg with both agreeing on a vo2-max of approximately 61.
So, if your 5-min power is less than 5w/kg, the formula used by Intevals.icu will give a higher estimate than the other formula (if your power is higher, Intervals.icu will give a relatively lower estimate).
I have no idea which formula gives a better estimate. I’m taking the calculation with a huge grain of salt, at least until my vo2-max is in the same range as the sample cyclists (at 46 mL/kg/min, I’m a decent bit below the sample).
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it has been estimating my vo2 max at 57-59 over the past few weeks. I had a lab test done on a bike last week and it measured 64.
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It would’ve been interesting to take your activity on Intervals and see what estimates intervals would have given.
The vo2-max from 5-min power estimate requires a 5-min all out effort, so it would not be able to generate a reasonable estimate from the ramp protocol of an actual vo2-max test.
The Intervals.icu vo2-max estimator is not like the Garmin or Apple Watch vo2-max estimators that use a complex model fit to estimate the the value from a variety of efforts. Intervals.icu is expecting an all-out 5-min effort and will give garbage (too low) result if used on a workout that does not contain such an interval.
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