Resting Metabolic Rate Tests

Resting Metabolic Rate (RMR) 

The Resting Metabolic Rate test is designed to measure the intake and output of Oxygen in your breath while at rest. This will tell you precisely how much energy you are actually consuming, without relying on models or averages.

What is it? 

The Resting Metabolic Rate test is one of the Spirometry tests, meaning it is measuring your breath intake and output. 

How does it work? 

Our bodies require 208ml of Oxygen in order to expend 1calorie. This is a tried and tested constant. Because we know this we can conclusively say that if we have taken in 2080ml of Oxygen, and then breathe out 2080ml of a mix of Oxygen and Carbon Dioxide which contains 1040ml of Oxygen, we know in that time, we have consumed 5 calories.

How else can I find this information?

The question we are seeking the answer to with the RMR test is ultimately ‘How much should I be eating?’

The only other way to do this is based on estimates which are based on population samples. Ever had a doctor or someone else tell you that because you are a man, you should be consuming 2500 calories, or 2000 for a woman?

But there are so many factors  which could make this ‘average’ very wrong. Levels of thyroid hormone, insulin, cortisol, and many others will affect your metabolism. The amount of muscle mass, you have and a host of other factors can have a dramatic effect on this.

How much does RMR testing cost? 

We have tried to keep our pricing as easy to understand as possible. For a full schedule of prices for all tests/scans please click here, but the basic pricing is below:

Number of tests Cost Validity Period
1 Scan/Test £135 3 months
2 Scans/Tests £235 12 months
3 Scans/Tests £325 12 months
4 Scans/Tests £385 12 months

What is the procedure? 

When you come in, we’ll sit you down for a few minutes before starting the test to let you relax. You’ll then be given a nose clip to ensure that all your breathing is through your mouth, and a breathing tube which you’ll have to breathe into normally for about 10 minutes. 

While taking the test we’ll encourage you to relax, recline, and rest as much as possible.

It is helpful to not have caffeine or other stimulants in the system when taking the test as this will affect the readings. Ideally you should not have exercised that day either, as this will also increase your metabolism for several hours post-workout.

How Accurate is the test?

Indirect Calorimetry  (IC: what we are doing with the RMR test)  is considered the gold standard of measuring RMR. This study in the Iranian Journal of Public Health compared the standard equations to indirect calorimetry, and found that in certain populations the equations were wildly inaccurate.

Further, there are countless studies which show that IC is understood in the scientific community as the gold standard for measuring a person’s RMR and getting to a detailed total Energy Expenditure. 

What do you get at the end? 

You’ll get a report showing you exactly how many calories you are burning at rest. This will give you accurate guidance on how many calories you should be eating in order to maintain weight or lose. 

As you can see from the example below – this client had a much faster than average metabolism owing to a very significant amount of muscle mass. 


RMR Results Table