VO2 max and training zones: your aerobic engine, measured

VO2 max is the maximum amount of oxygen your body can use during hard exercise, and it is one of the best single measures of your aerobic fitness, or "engine"; testing it, and setting your training zones from real data, lets you train in the right intensity rather than guessing. The higher your VO2 max, the more oxygen your muscles can use to produce energy, which is why it tracks so closely with endurance performance. Just as useful for everyday training is what a proper test gives you alongside it: your personal training zones, so your easy days are genuinely easy and your hard efforts are genuinely hard.

What VO2 max actually tells you

VO2 max is measured in millilitres of oxygen per kilogram of body weight per minute, and it reflects how well your heart, lungs and muscles work together to deliver and use oxygen. Because endurance performance is fundamentally about sustaining energy production aerobically, VO2 max is one of the most reliable indicators of cardiorespiratory fitness. It is not the only thing that matters, efficiency, threshold and durability count too, but it is the foundational number that describes the size of your aerobic engine, and it responds to training, so it is worth knowing and tracking.

What counts as a good VO2 max?

The honest answer is "it depends," which is why context matters more than a single league table. A good score depends on your age, sex and sport, so the sensible approach is to compare your result to your age and sex band first, then to others in your sport tested the same way. VO2 max typically peaks in the early twenties and gradually declines with age, and women's values are on average lower than men's for physiological reasons. Rather than chasing an arbitrary number, the useful comparison is you against your own baseline over time, which is exactly what re-testing provides.

As a rough guide, here is how directly measured VO2 max (ml/kg/min) compares across age and sex, using US reference data from the FRIEND registry of laboratory exercise tests. Find your age band and sex, then see where your number sits.

Men (VO2 max, ml/kg/min)

Women (VO2 max, ml/kg/min)

Values are ml/kg/min from treadmill cardiopulmonary exercise testing (Kaminsky et al., 2015). These are population reference points, not targets or a diagnosis; what counts as a good score also depends on your sport and your own history, so compare like with like.

Why training zones are the practical payoff

For everyday training, your zones may matter even more than the headline number. Training zones define the intensities, easy, moderate, threshold, hard, that develop different parts of your fitness, and getting them right is what makes a training plan work. The problem is that zones based on generic formulas or a smartwatch's estimate can be wrong, leaving you training too hard on easy days and not hard enough on key sessions, sometimes for months. Setting your zones from an actual test means your training targets your physiology, not an average. Why training by feel can fail goes deeper on the practical trap.

An honest word on measurement

Precision matters here, so we describe our method accurately. The uVida is a breath-by-breath metabolic analyser, the same class of technology used in sports-science laboratories, and we take the test to the point of exhaustion. That means it measures the oxygen your body actually uses at maximal effort, rather than estimating your VO2 max from a formula or a smartwatch. In a validation study, the uVida (DYNOSTICS) system was compared against a laboratory reference analyser and its peak oxygen-uptake readings differed by only about 1% on average, with strong agreement across the other breath-gas measures. As with any physiological test there is a small margin of natural day-to-day variability, and the published evidence base is still growing, but this is a direct, individual measurement of your aerobic engine, interpreted with you and turned into your training zones. For a broader primer on the number itself, see what is VO2 max .

Why Hanbury Health is different

At Hanbury, VO2 max and training-zone testing is done with a uVida metabolic mask, a breath-by-breath metabolic analyser worn while you work to exhaustion, as part of the Performance Blueprint, and, crucially, your results are read with you by an expert and set into a plan, rather than printed by an app. It sits alongside body composition, strength and movement testing, so your aerobic engine is understood in the context of the rest of your performance, and it connects into the Hanbury Method of Test, Train, Track and Transform, with re-testing to prove your training is working. It is available from Level 2 of the Blueprint (£495).