By Rory Sutherland, MSCS
VO2, or volume of oxygen consumption, is a term you’re going to be hearing more about.
This measure of metabolism, specifically of oxygen, is the most important measure we have to globally evaluate the cardiorespiratory system. Since VO2 was first discovered in 1920 by AV Hill and colleagues, it’s correlation with health and longevity is backed by a substantial amount of research. Better yet, we have a device in office that can perform this gold-standard test known as “VO2max.” Below I’ve reviewed some powerful research evaluating the prognostic value of testing your VO2max.
In 2012, a study published in the Journal of the American Heart Association aimed to investigate the association between VO2 scores (maximal scores, specifically) and long-term survival in 11,190 “low-risk” adults.
The results of the study showed that higher levels of cardiorespiratory fitness were associated with a lower risk of all-cause mortality and cardiovascular disease mortality. Specifically, for every 1 metabolic equivalent (MET) increase in VO2max, there was an 11% reduction in all-cause mortality and an 18% reduction in cardiovascular disease mortality. This was measured at the start of a 30 year period in which they tracked subject mortality.
Another study published in JAMA (2009), specifically a meta analysis including 33 studies with a total of 102,980 “low risk” participants, found that an increase of 1-MET in VO2max is associated with a 13% and 15% reduction in the risk of all-cause mortality and cardiovascular disease, respectively. These findings suggest that even a small increase in VO2max may be significant from a clinical perspective.
The study also compared the effects of a 1-MET increase in VO2max to other risk factors of metabolic syndrome. They found this increase was comparable to a reduction in:
- Waist circumference by 7 cm
- Systolic BP by 5 mmHg
- Triglyceride level by 1 mmol/L
- Fasting plasma glucose by 1 mmol/L
While VO2max testing does require a very strenuous effort, research evaluating the safety of such tests have concluded they are in fact, safe. One bit of research published in Circulation saw only 6 major events in 71,914 tests, one of which was fatal, and this was 34 years ago (Gibbons, 1989). Another study in Circulation of at-risk patients > 75 years old, specifically those with congestive heart failure, hypertrophic cardiomyopathy, pulmonary hypertension and aortic stenosis, saw only 8 events in 5060 tests with 4250 unique patients (Skalski, 2012). None were fatal.
For the fitness enthusiast – a high VO2max is a prerequisite to improved performance in all aspects of fitness. Improving to or maintaining a high VO2 max means you will:
- Have improved endurance – obviously
- Improve your recovery time during exercise and between exercise sessions
- Maintain a lower resting heart rate
- Improve your heart rate variability (stress response and resilience)