# Calculating Calorie Expenditure from VO2

A friend of mine tries to calculate this, and I’ve googled about a lot to find a reasonable formula.

What we know is: gender = man, height = 1.80m, weight = 120kg, energy expenditure (VO2): 3.2 L/min, and time (cardio): 40 min.

I’ve found a few formulas on the internet that use the latter three, for example (From livestrong.com): cal = (METs * 3.5 * weight) / 200 * time

But I have no idea where they got 200 from. I’ve also found more simple ones: cal = METs * weight * time (hours)

But we should be able to derive calories directly from the energy expenditure (VO2), as this is - as I understand - proportional to calorie expenditure (?).

It seems like there are a million different formulas for the same thing. I’ve never understood how such a simple thing can be made this confusing. This is worse than my linear algebra in n’th dimensions in uni!!

Any ideas are greatly appreciated!

jodles

Well, calculating stuff like this is fun for those of us who like math. But the reality of it is that it’s best for comparative purposes only (which workout would burn more calories during the workout). None of the formulas take into account what happens after the workout is over, such as the EPOC effect or cumulative rise in metabolism.

As such, a basic formula, such as the one from livestrong, is good enough for practical purposes.