Resting metabolic rate (RMR) is the energy your body uses at rest to keep you alive and functioning: breathing, circulation, temperature regulation and repairing tissue. For most people it is the largest part of daily energy use.
Measured vs estimated
Most calorie calculators estimate RMR from age, height, weight and sex. Those formulas work reasonably well on average but can be off for an individual. An RMR test measures the oxygen you use and carbon dioxide you produce at rest, so the figure is based on you rather than a population average.
RMR is not your daily target
This is the most important point. RMR is only your energy use at rest. Your total daily needs also include everyday movement, digesting food and — for athletes — training, which can add a lot. Eating to your RMR alone would leave most active people underfuelled.
How to use your result
- As a starting point for fuelling. Add your activity and training on top to estimate daily needs.
- To check for underfuelling. A lower-than-expected measured value can be one sign worth discussing with a qualified professional.
- To track change. Repeat the test under the same conditions to see how it moves over time.
Preparing for the test
Because the test measures you at rest, preparation matters. Your booking confirmation explains exactly what to do before you arrive.
Pair RMR with body composition for a fuller picture — see all body and metabolism tests.
Further reading: safefood.
