High-Intensity Interval Training

High-intensity interval training, or HIIT, is a commonly used term in exercise circles. Generally, this refers to a form of exercise which switches back and forth between intervals of high-intensity and intervals of low-intensity exercise. In contrast to HIIT, there's moderate intensity continuous training (MICT), where one exercises at a consistent, medium intensity. There is some variation between what defines "high/medium/low intensity" and how long these intervals are, but HIIT is commonly seen as one of the most effective forms of exercise.

In a systematic review from September 2013, the researchers looked at 13 studies which included patients with chronic lifestyle-related diseases like coronary heart disease, obesity, and hypertension. Although there were some differences between studies (like how they defined levels of intensity and the length of exercise), generally HIIT was more effective than MICT in increasing max O2 volume (breathing ability) and cardiac function, and lowering blood pressure, fasting glucose, and oxidative stress/inflammation. In fact, HIIT even showed a greater improvement in quality of life and enjoyment of exercise!

Take home message: There's overwhelming evidence that exercise is beneficial for health, but not all exercise is the same. Although HIIT seems to have greater benefits than MICT, there are other considerations like safety and physical constraints. Consult your physician if a prescribed exercise plan is right for you, and what type of exercises would most benefit you.


Sources:

1.

Weston KS, Wisløff U, Coombes JS. High-intensity interval training in patients with lifestyle-induced cardiometabolic disease: a systematic review and meta-analysis. Br J Sports Med. 2013 Oct 21;bjsports–2013–092576.