GLOSSARY

Harris–Benedict Equation Table

Original Harris–Benedict equations, rounded coefficients, kcal/day; W in kg, H in cm and A in years. These are population predictions.

Harris–Benedict Equation refers to a family of equations estimating basal or resting expenditure from body characteristics. Original and revised Harris-Benedict versions use different coefficients, so the exact version must be named.

Prediction equations link measured characteristics such as mass, height, age or fat-free mass to an expected resting expenditure in a reference population. Versions and required units differ, and an equation's output is not a direct metabolic test. An athlete can differ from the development sample. State the equation version and inputs, and reassess its usefulness against appropriate measurements and real-world trends. A discrepancy should prompt evaluation of both prediction and measurement conditions rather than an automatic diagnosis of metabolic damage.

Basal measurements require stricter conditions than many resting measurements, including a postabsorptive state, physical rest and a thermoneutral environment. Resting energy expenditure and basal metabolic rate are closely related but not automatically interchangeable. Recent training, food, stimulants, illness and measurement procedures can affect results. A prediction equation supplies an estimate for a population and its inputs, whereas properly performed indirect calorimetry measures respiratory exchange under the conditions of that particular test.

Total expenditure includes energy needed at rest, the thermic effect of food and physical activity. Planned exercise is only part of activity expenditure. Work, walking and spontaneous movement can also matter. When an estimate already includes a component, adding it again double counts energy. Establish whether an exercise value is gross or net of resting expenditure, and use the same convention when comparing days or combining wearable estimates with a daily energy model.