Resting metabolic rate
Resting Metabolic Rate (RMR) is a form of metabolism measurement that measures the amount of energy used by the bodies of animals in a relaxed, but not post-absorptive, state. RMR measurements require the animals be in a thermal neutral zone (or a preferred temperature range for bradymetabolic animals) and relaxed. Animals are given the freedom to move around and eat, but are not allowed to perform any strenuous exercises. This differs from basal metabolic rate measurements in that it does not require that animals meet the strict criteria necessary for a proper BMR measurement. The less strict criteria of RMR measurements makes them more applicable for many biological studies.
- , where LBM is the lean body mass in kg
Since lean body mass is metabolically active vs. fat cells which need very few calories to be sustained, these formula tend to be more accurate, especially with athletes who have above average lean mass and little body fat.
To calculate daily calorie needs, the RMR value is multiplied by a factor with a value between 1.2 and 1.9, depending on the person's physical activity level.
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- McNab, B. K. 1997. On the Utility of Uniformity in the Definition of Basal Rate of Metabolism. Physiol. Zool. Vol.70; 718–720.