Metabolism, quite simply, is the conversion of food to energy.
Metabolic rate is a measure of how much food, or fat, is converted to energy in a day. Resting metabolic rate (RMR) is the measurement of how much food, or energy, is required to maintain basic body functions such as heartbeat, breathing, and maintenance of body heat while you are in a state of rest. That energy is expressed in calories per day. So an RMR test shows how many calories you burn at rest, doing nothing more than sitting in a chair.
How does it work?
Indirect calorimetry (a measurement of metabolic rate) relies on the fact that burning 1 calorie (Kilocalorie) requires 208.06 milliliters of oxygen. Because of this very direct relationship between caloric burn and oxygen consumed, measurements of oxygen uptake (VO2) and caloric burn rate are virtually interchangeable.
Oxygen uptake requires a precise measurement of the volume of expired air and of the concentrations of oxygen in the inspired and expired air. The process requires that all of the air a person breathes out be collected and analysed while they rest quietly.
- The average RMR for men is 1600 Calories per day.
- The average RMR for women is 1400 Calories per day.
- On the day
It is desirable to measure a person’s metabolic rate at a true resting level. To ensure one is at rest, we recommend the following preparation:
- Avoid eating a meal 4 hours before the test.
- Avoid exercising on the day of testing.
- If possible, avoid the use of stimulants such as caffeine prior to testing.
- During the test it will be important to get into a comfortable position and relax as much as possible.
- Keep lips sealed lightly around the mouthpiece. It is important that all the air breathed out is analysed.
- Breath normally for 10 minutes.
- Test complete!