Weir formula

The Weir formula is a formula used in indirect calorimetry, relating metabolic rate to oxygen consumption and carbon dioxide production. According to one source, it says:^[1]

Metabolic rate (kcal per day) = 1.44 (3.94 VO₂ + 1.11 VCO₂)

where VO₂ is oxygen consumption in millilitres per minute and VCO₂ is the rate of carbon dioxide production in millilitres per minute. The formula can also be written for units of calories per minute:

Metabolic rate (cal per minute) = 3.94 VO₂ + 1.11 VCO₂

Another source gives^[2]

Energy (kcal/min) = (respiration in L/min times change in percentage oxygen) / 20

This corresponds to:

Metabolic rate (cal per minute) = 5 (VO₂ in ml/min)

References

^ Patrick Burns; Michael Snow. "Indirect Calorimetry" (PDF).
^ "Techniques available for measuring energy expenditure". United Nations University.

Weir, J.B. de V., "New Methods for Calculating Metabolic Rate with Special Reference to Protein Metabolism," J. Physiol., 109: 1-9. (1949). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1392602/

[1] Patrick Burns; Michael Snow. "Indirect Calorimetry" (PDF).

[2] "Techniques available for measuring energy expenditure". United Nations University.

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