Variables
Description
What is this formula?
The Metabolic Energy Expenditure formula estimates the rate at which the body consumes energy based on oxygen consumption. Under typical physiological conditions, approximately 5 kilocalories are released for each liter of oxygen utilized.
When to use it
Use this formula when estimating caloric expenditure, metabolic rate, exercise energy requirements, or energy consumption in critically ill patients.
Example
Data:
VO2 = 0.25 L O₂/min
Formula:
EE = VO₂ × 5
Substitution:
EE = 0.25 × 5
Result:
EE = 1.25 kcal/min
The body is expending approximately 1.25 kilocalories per minute.
Applications
- Exercise physiology
- Sports science
- Nutrition
- Critical care medicine
- Indirect calorimetry
Note
This formula is an approximation based on the average caloric equivalent of oxygen. The actual energy released per liter of oxygen depends on the respiratory quotient and the type of substrate being metabolized (fat, carbohydrate, or protein). More precise methods use respiratory gas analysis and indirect calorimetry equations such as the Weir equation.