With the growing body of evidence finding High-Intensity Interval Training (HIIT) to be an effective exercise program, researchers set out to see just how efficient HIIT really is and their findings are incredible! Results from the 2016 publication¹ showed HIIT to be 400% more efficient than Moderate-Intensity Continuous Training (MICT). Over a 12 week program, a total of 30 minutes each week of the HIIT protocol training was as effective as 150 minutes each week of MICT. That’s 20% of the time needed to get the same results. Wow, but that’s not all. Of those 30 minutes each week, only 3 minutes are actually spent on intense exercise. Each week consisted of 3 days of 10-minute training bouts, in which each session had a 2-minute warm up, 3-minute cool down, and 2 minutes of low-intensity work separating 3 20-second maximum all-out efforts. The MICT training protocol had the same warm up and cool down with 45 minutes of continuous training. Excluding the time spent on the warm up and cool down would actually imply HIIT is 800% more efficient!

Perhaps more importantly, both programs significantly improved cardiorespiratory fitness, insulin sensitivity, and skeletal muscle mitochondrial content. Peak oxygen uptake (VO_2peak) increased by 19% in both training groups and had improved by roughly 12% after just 6 weeks of the program. The absolute change in VO_2peak was roughly equivalent to 1.7 METs. What does that mean? Well there are vast health benefits and significant improvement in survival rates that can be achieved from an improvement of just 1 MET. (For more info about the Metabolic Equivalent of Task (MET) check out our post “How to Live Longer and Improve Quality of Life”.

More recently, the significant relationship between exercise capacity (as measured by VO_2peak) and longevity was confirmed in the longest study of its kind, following up with almost 800 adult men after 45 years. Published in July 2016², researchers found exercise capacity to be the 2nd greatest predictor of death, behind only smoking. Interestingly, the results showed aerobic capacity information was roughly 40% above single risk factors, implying that exercise reduces risk through multiple pathways improving general health, not just cardiovascular health.