Research has found that after adjusting for age, peak exercise capacity is the single greatest predictor of the risk of death. Peak exercise capacity was a greater predictor of mortality than smoking, hypertension, diabetes, and history of congestive heart failure. That is just mind blowing. When thinking about the biggest drivers of life expectancies, we typically think about gender and smoking status. Actuarial life tables (often used to determine how much your life insurance costs) are generally constructed separately for males and females and for smokers and non-smokers as women tend to live longer than men and non-smokers live longer than smokers. However, peak exercise capacity appears to be an even more important factor than smoking, which doesn’t diminish the importance of not smoking, but rather highlights what is to be gained from improving exercise capacity.

The Metabolic Equivalent of Task (MET) is a measure expressing the energy cost of physical activities. 1 MET is defined as the energy expended by a person at rest, sitting quietly and is roughly equivalent to 3.5 ml of oxygen per kilogram of body mass per minute. It is now well accepted that health and longevity are greatly influenced by exercise. A 2002 study in the New England Journal of Medicine¹ found a 12% improvement in survival for each 1 MET increase in exercise capacity. Other studies have found similar results with reductions in mortality ranging from 8-18% per 1 MET increase in exercise capacity.

So increasing exercise capacity by just 1 MET could improve survival rates by over 10%, but how easy is it to do? Well, that depends on a lot of variables including your current fitness and activity levels. Regardless, countless studies have shown that short bouts of High-Intensity Interval Training (HIIT) can significantly improve aerobic capacity, with minimum time commitments over a short period of time.

A 2015 study in PLOS ONE² showed that on average, just 3 18 minute HIIT sessions per week over 10 weeks resulted in an average of close to a 1 MET increase. Several other studies have found similar results across a range of program durations, varying levels of intensity, and an array of weekly training times. A 2010 study found significant improvement for both men and women in VO_2max (maximal oxygen consumption) in just 6 HIIT sessions over a 3 week period³.

What does all this mean? Your life is in your hands and time is no longer an excuse. With maximum effort, in under an hour each week, you can significantly enhance your health and increase your life expectancy.