Your VO2 max gives you a good sense of your fitness and aerobic endurance and according to an incredible amount of scientific evidence showing that your cardio fitness reflects your overall health. In fact, long-term, your cardio fitness is linked not only to how long you will live (life span) but also to how many healthy years of life you will have (health span).

Poor cardio fitness is clearly linked to an increased risk of developing and even dying from a serious medical condition. Cardio fitness is also an important health risk factor along with risk factors like smoking, having high blood pressure or high cholesterol or type 2 diabetes.

As cardio fitness levels increase, our risk of conditions like hypertension (chronic high blood pressure) and dyslipidemia (abnormal levels of fat in the blood, including high cholesterol) drop. We also lower our risk of stroke, heart disease, diabetes, and cancer, and even our risk of developing mental health disorders (like anxiety and depression) and conditions as debilitating as Alzheimer's disease and dementia.

Your cardio fitness shows how well your respiratory and circulatory systems work to make sure your muscles have oxygen when you exercise. These systems work together to get oxygen-rich blood from the lungs to the heart and out to the body (to your muscles), and to bring blood carrying carbon dioxide back to the lungs.

The amount of oxygen you are able to use when you're pushing yourself to your limits, shows not only how well your heart's pumping blood to your muscles but also how well your muscles are taking up oxygen to produce energy in the muscle cells - so that you can keep going... up to the point you can't sustain that level of effort anymore. That's the maximum amount of oxygen your body can take in while you're exercising. That is your VO2 max.

Your cardiorespiratory fitness is measured through VO2 max. The higher your VO2 max, the better your aerobic endurance. In other words, the better your ability to use oxygen for longer, when exercising