RMR and MET Testing Canberra: What They Actually Measure

Ask most people what test they want and they will say VO2max. Ask what they actually want to know, how many calories they burn at rest and how their body shifts from burning fat to burning carbohydrate as effort climbs, and the honest answer is a different test: RMR and MET testing.

Resting metabolic rate and metabolic equivalent testing measure exactly those two things, directly, through the air you breathe. Not estimated from a height and weight formula. Measured.

Why VO2max is not the number you are actually chasing

VO2max gets requested because it is the number everyone has heard of. It is genuinely useful in its own right, but it answers “what is my ceiling,” not “what am I burning right now, and how much do I need to eat to keep going.”

RMR and MET testing answer that second question, and for most riders training seriously without racing at the elite end, it is the more actionable number of the two.

What resting metabolic rate actually measures

RMR is measured lying still, first thing in the morning, having not eaten. A mask captures every breath for a set period, and the ratio of oxygen consumed to carbon dioxide produced calculates exactly how many calories your body burns simply existing, no training, no digestion, nothing but staying alive.

That number matters more than it sounds like it should. A generic formula built from height, weight, age and sex gives an estimate that can be out by several hundred calories a day in either direction. For someone managing body composition alongside a heavy training load, or recovering from a period of underfuelling, several hundred calories a day is the entire margin they are working with. Guessing it is not good enough.

What MET testing adds on top

Once resting rate is established, the same equipment tracks how fuel use shifts as intensity climbs during a graded test. At low intensity, most of your energy comes from fat. As effort increases, the mix shifts progressively toward carbohydrate, and at race intensity for most endurance events, carbohydrate is doing the majority of the work.

Metabolic equivalent, or MET, values describe the intensity of an effort relative to resting rate: one MET is your resting burn rate, and the number climbs from there as you work harder. Tracked against oxygen uptake and the fat-versus-carbohydrate ratio, it produces a fuelling curve specific to you, not “eat 60 to 90 grams of carbohydrate per hour,” which is a population average, but a number derived from how your body actually burns fuel at the intensity you race or ride at.

Indirect calorimetry versus a formula

Every RMR calculator online is built on population averages, applied to you as an individual. It has never measured your breath, your thyroid function, your muscle mass, or the metabolic cost of the training you have actually been doing. It is a reasonable starting guess for someone who has never been tested, and nothing more.

Indirect calorimetry, measuring the gases you actually exchange, removes the guessing. It is the same underlying principle used in hospital metabolic carts, applied here to answer a training and nutrition question rather than a clinical one.

Who this is actually for

Three groups get the most out of RMR and MET testing specifically, as distinct from a straight VO2max test: athletes trying to change body composition without losing power, who need a real baseline rather than a guess before cutting calories; endurance athletes preparing for long events, who need an individual carbohydrate-per-hour number rather than a population average, because getting fuelling wrong is a more common way to lose a race than being under-fit; and anyone who has been under-eating for an extended period, where a suppressed resting rate is one of the clearer objective signs that something needs to change before more training gets added on top.

What a session involves

RMR is measured first, lying still, ideally first thing in the morning before eating or training. MET testing follows as a graded effort test on the modality you actually compete in, wearing the same mask, stepping the workload up at fixed intervals until the fuel mix and oxygen cost at each stage are captured.

As with VO2max testing, preparation affects the result. What you ate the day before, how hydrated you are, and how fresh you are from training will all move the numbers. That is why, like other lab testing at UpHill, it is booked by phone rather than online: there is a short conversation first about how to prepare properly.

A worked example

Take two athletes preparing for the same 70.3, similar power numbers, similar VO2max. One consistently runs out of energy at the same point on long rides. The other does not. A generic 60-gram-per-hour fuelling target treats them identically.

MET testing on the first shows a resting rate well below what a formula would have predicted, and a carbohydrate demand at race intensity closer to 90 grams per hour than 60. The second tests almost exactly at the population average. Same event, same distance, genuinely different fuelling plans, and the only way to know which one you are is to measure it.

Where this fits with everything else

A metabolic test tells you what you are burning and when. A physiotherapy assessment tells you whether your body can actually hold up to the training load that number implies. Between the two, you get a genuinely individual picture instead of separate formulas stacked on top of each other and called a plan.

Want your actual numbers instead of a formula’s guess? Book an appointment at UpHill Performance, or call 0438 284 788 for lab testing.