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Basal or Resting Metabolic Rate

Resting Metabolic Rate (RMR) and Basal Metabolic Rate (BMR) are measures of resting energy expenditure, which can be helpful in assisting patients with weight loss. BMR and RMR represent the minimum amount of energy required to keep your body functioning, including your heart beating, lungs breathing, and maintaining normal body temperature. Although the terms BMR and RMR are sometimes used interchangeably, they are measured under different conditions and have slightly different interpretation.

• aim: to directly determine resting oxygen consumption as a measure of metabolic rate at rest.
• equipment required: O2 and CO2 analyzers, ventilation measurement by a pnuemotach or turbine ventilometer (as used for VO2 measurement). There are also specific devices to measure metabolic rate such as the BodyGem.
• procedure: The difference between BMR and RMR is in the subject preparation. BMR measurements are typically taken in a darkened room upon waking after 8 hours of sleep with 12 hours of fasting to ensure that the digestive system is inactive, and with the subject resting in a reclining position. On the other hand RMR measurements are typically taken under less restricted conditions than BMR. For BMR you should avoid any exercise or stressful situations for at least two hours prior to the test, as well as eating a meal or ingesting caffeine or other stimulants in the previous 4 hours. Smoking should also be avoided during that time. During the test the subject should be seated or reclining comfortably in a quiet room set at a neutral temperature, and not speaking, reading or watching television so that they can fully relax. Rest the subject for at least 10 minutes in these conditions before starting the measurements.

• measurement: The apparatus measure the oxygen consumption of the body (VO2). Measurements should be taken for at least 10-20 minutes or until the values have stabilized. The results can show if you have increased or decreased metabolism, and whether your body primarily uses fats or carbohydrates for energy. See also equations for calculating BMR and RMR.
• disadvantages: this test requires expensive equipment and is labor intensive.

• comments: metabolic rate measurements can change over time, and are affected by body weight, height and age.

Related Pages

• Equations for calculating BMR and RMR
• more Health Fitness Tests
• Calculating your BMR for weight loss.
• Calculating Energy Expenditure