How do you correlate HRmax to VO2 max? Is there a formula for this? For example, I came across a rationale that said 60-90% HRmax correlates to 50-85% VO2 max. How would I know this?

It is possible to determine exercise intensity level as a percentage of maximal oxygen consumption (VO2max) from known heart rates and vice versa. To determine the actual VO2max itself, a VO2max maximal physical exertion test is performed in a controlled setting with sophisticated laboratory equipment. However, without actually knowing what the VO2max value is, you can still convert exercise intensity level from a heart rate to a percentage of VO2max, and vice versa, since there is a known linear relationship between the two. Please see this link for more on VO2max and HRMax conversions.

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