What it is

VO2 max is the most oxygen your body can use during hard exercise. It reflects how well your lungs, heart, circulation, and muscles work together. PNOĒ measures it directly from your breath during a graded exercise test, instead of estimating it from heart rate or a formula. The same test maps your ventilatory thresholds and how your fuel use shifts between fat and carbohydrate as intensity rises.

 

Why it matters

Cardiorespiratory fitness is strongly linked to long-term health, and the American Heart Association has called for it to be treated as a clinical vital sign. Your measured thresholds set training zones based on your own physiology rather than age-based formulas. Retesting shows whether your training is actually moving the number.

 

What to expect

You wear a fitted mask connected to the portable PNOĒ analyzer and a heart-rate chest strap, then exercise on a treadmill or bike in workout clothes and shoes. After a 3-minute warm-up, the intensity rises every minute for about 9–12 minutes until you reach your maximum effort, followed by a short recovery. Beforehand, skip food, caffeine, nicotine, and energy drinks for at least 3 hours (5 hours if you are also doing an RMR test that visit), and avoid intense exercise or any workout over an hour in the 24 hours before.

 

Who should not test

Maximal exercise testing is not appropriate with an acute or unstable heart condition, such as a recent heart attack, unstable chest pain, an uncontrolled heart rhythm problem, decompensated heart failure, or an acute blood clot. PNOĒ advises that anyone with known or suspected heart or lung disease be tested in a physician-supervised clinical lab with ECG monitoring. If you have a heart, lung, metabolic, or kidney condition, or get chest pain, dizziness, or unusual shortness of breath with exertion, check with your physician and let us know before booking.