VO₂ max and RMR testing at Breathe
Get to know the body doing the work.
Whether you’re building fitness, working towards a goal or trying to understand your energy needs, your breath has plenty to tell us. VO₂ max testing measures your aerobic fitness, while resting metabolic rate testing measures the energy your body uses at rest. We’ll explain your results and help you understand how to put them to use.
- Aerobic fitness measured through your breath
- Training zones based on your test
- Your energy use at rest
Understand your fitness
Find out how well your body uses oxygen.
When you exercise, your lungs bring in oxygen, your heart delivers it and your muscles use it to produce energy. VO₂ max describes the highest rate at which your body can use that oxygen during intense exercise, giving you an established measure of aerobic fitness.
Start gently and build the effort.
You wear a fitted mask that measures your breathing while the exercise gradually becomes harder. Alongside your heart rate, the oxygen and carbon dioxide measurements show how your body responds as the demand increases.
Give your training more direction.
Your results can help you understand what an easy session should feel like, where harder efforts begin and how to pace your training. That’s useful whether you’re preparing for an event or building a routine you can sustain.
A starting point that belongs to you.
We’ll explain your oxygen-uptake result, how it compares with relevant reference values and what the wider test reveals about your exercise response. You’ll have something concrete to work with and a baseline for future comparisons.
What to expect
We’ll guide you through the effort.
Before your appointment, we’ll explain how to prepare so you arrive rested and ready. On the day, there’s time to talk through the test, get comfortable with the equipment and ask anything that’s on your mind.
First, a conversation.
We’ll discuss your health, medication, activity levels and what you want to learn, then check that the test is appropriate for you.
Get comfortable and warm up.
We’ll fit your breathing mask and heart-rate monitor, explain how to communicate during the test and begin with a gentle warm-up.
Build the effort gradually.
The exercise becomes progressively harder while we monitor your response and guide you through it. You can ask to stop at any point, and we may stop the test earlier if needed.
Recover, then understand the results.
Once you’ve cooled down and recovered, we’ll talk through your results in plain English and explain how they relate to your goals.
Numbers you can use
More than a fitness score.
Your oxygen uptake
Your highest measured oxygen uptake during the test, with an explanation of what it says about your aerobic fitness and how it compares with relevant reference values.
Your breathing thresholds
The points where your breathing response changes as exercise becomes harder, helping distinguish sustainable efforts from more demanding work.
Your training zones
Heart-rate guidance informed by your measured response, helping you choose an appropriate intensity for different sessions.
Your fuel use
Where the testing protocol allows, gas measurements can estimate the contribution of fat and carbohydrate at suitable exercise intensities, adding context to conversations about pacing and fuelling.
Understand your energy needs
What it takes to keep you going.
Even when you’re lying still, your body is busy. Breathing, circulating blood, regulating temperature and maintaining your organs all require energy. Resting metabolic rate, or RMR, measures how much energy your body uses to carry out that work.
During the test, you rest comfortably while we analyse your breathing. The result is expressed as calories per day, giving you a measured starting point for understanding your energy needs.
Most calorie calculators use your height, weight, age and sex to predict this figure. Measuring it adds information about you as an individual, which can be useful when planning nutrition around training, weight maintenance, weight gain or weight loss.
RMR is only part of your daily energy use. Movement, exercise and digestion also contribute, so your result is a starting point for discussing food intake, rather than a daily calorie target on its own.
Preparing for your test
- Follow the fasting instructions provided before your appointment.
- Follow the guidance on exercise, caffeine, nicotine and alcohol.
- Allow time to settle and rest when you arrive.
- Tell us about medication or health conditions that could affect preparation.
From our members
What they learnt about themselves.
Why they booked, what surprised them and how they used their results. Hear from members who wanted a clearer understanding of their fitness and energy needs.
Watch or lab
Your watch guesses. This measures.
Your watch estimates VO₂ max from information such as your heart rate, pace or power. Our test measures your oxygen uptake through your breath as you exercise, giving you a closer look at your fitness and practical information to guide your training.
A smartwatch estimate
- Calculated from activity data using an algorithm.
- Useful for following trends during everyday training.
- Doesn’t measure the oxygen you consume.
A measured test at Breathe
- Measures oxygen uptake through analysis of your breathing.
- Identifies exercise thresholds to inform your training zones.
- Establishes a baseline you can return to and compare over time.
Follow your progress
Give yourself something to compare with.
Your first test establishes a starting point. Testing again after a period of training or a course at Breathe lets you see what has changed alongside how you feel.
Researchers use the same before-and-after approach. In a controlled study published in Sports Medicine – Open, a course of hyperbaric oxygen was associated with improvements in measured aerobic fitness and a marker of mitochondrial mass.
Increase in the HBOT group’s average maximal oxygen uptake, calculated from the reported group averages.
Average increase in a marker of mitochondrial mass in the small subgroup assessed through muscle biopsies.
Delivered over eight weeks, while participants maintained their usual training.
This double-blind, randomised study analysed 31 healthy athletes aged 40–50. HBOT involved 60 minutes breathing 100% oxygen at 2 ATA, compared with a sham treatment using ordinary air near normal pressure. The mitochondrial-mass analysis included 12 participants. These findings relate to that specific protocol and cannot be assumed for lower-pressure sessions.
Your questions, answered
Before you book.
Should I choose VO₂ max testing, RMR testing or both?
VO₂ max testing is useful if you want to understand your aerobic fitness and exercise intensity. RMR testing measures your energy use at rest and can inform nutrition planning. If both interest you, tell us what you’re working towards and we’ll explain how the tests fit together.
How much do the tests cost?
Get in touch for the current prices and a clear explanation of what each appointment includes. We’ll confirm everything before you book.
Do I need to be an athlete?
No. You might be training regularly, returning to exercise or simply interested in understanding your fitness. We’ll review your health and current activity first, because a maximal exercise test needs to be appropriate for you.
How hard is the VO₂ max test?
It starts gently and becomes progressively harder, with the aim of measuring your highest achievable oxygen uptake. The final stages can feel demanding, but you remain in control and can ask to stop at any time. We also monitor your response and may stop the test earlier if needed.
What is a good VO₂ max for my age?
Your result can be compared with reference values for your age and sex, but those comparisons are only part of the picture. Your goals, health, training background and test method also matter. We’ll explain the result in context rather than leave you with a score and a ranking.
Does my weight affect the result?
VO₂ max is often expressed relative to body weight, in millilitres of oxygen per kilogram per minute. That means a change in weight can affect this number. When comparing tests, we can also consider your absolute oxygen uptake and exercise performance to understand the wider picture.
Is this the same as a hospital exercise test?
This service focuses on fitness and metabolic assessment. It does not replace a clinical investigation of chest pain, unexplained breathlessness or another medical concern. Tell us about any symptoms or relevant conditions before booking so we can advise on the appropriate next step.
How is this different from the VO₂ max on my watch?
Your watch calculates an estimate from information such as your heart rate and pace or power. Our test measures oxygen uptake through your breathing and provides additional information about exercise thresholds and training zones. Your watch is useful for following everyday trends; testing gives you a measured baseline.
Will RMR tell me exactly how many calories to eat?
It measures the energy your body uses at rest. To estimate your overall needs, you also need to consider activity, exercise, digestion and your goals. We’ll explain how your result fits into that wider calculation.
Can I have both tests on the same day?
Speak to us before booking them together. RMR requires carefully controlled resting conditions, while VO₂ max involves strenuous exercise, so preparation and the order of testing matter. We’ll explain the scheduling options that fit our testing protocol.
How should I prepare?
We’ll send instructions specific to your appointment, covering food, drink, exercise and anything else that could affect the measurements. RMR preparation differs from VO₂ max preparation, so follow the instructions for the test you’ve booked. Don’t change prescribed medication without advice from your treating clinician.
How often should I retest?
A retest can be useful after a meaningful period of training or a change in your circumstances. The timing depends on what you’re measuring and why, so we’ll discuss an appropriate interval rather than recommend the same schedule to everyone.
Will someone explain my results?
Yes. We’ll walk you through the findings in plain English, explain what the numbers mean and relate them to the goals you discussed with us. Bring your questions; understanding the results is part of the appointment.
Your next step
Start with what you want to understand.
Whether you’re looking for clearer training zones, a starting point for nutrition planning or a way to follow your progress, tell us what brings you here. We’ll help you choose the appropriate test and explain what happens next.