High Intensity Interval Training (HIIT)
High intensity interval training HIIT is defined as short bouts of high intensity exercise at perceived exertion of about 8/10 effort with complete or light recovery between bouts of high intensity exercise. The scientific literature subcategories high intensity interval training into low volume and high volume intensity interval training
Low volume HIIT is defined as less than 15 minutes of high intensity exercise
High volume HIIT is greater than 15 minutes of high intensity exercise
Both low and high volume HIIT do not include rest periods
Low volume HIIT is continually being investigated by researchers in healthy and clinical populations because of its time efficient nature and reported health benefits.
Recent research and trials has revealed low volume HIIT can bring about similar or even greater improvements in aerobic fitness and cardiometabolic health such as glucose control, blood pressure and cardiac function compared with moderate intensity continuous training or high volume HIIT
A study of adults with type 2 diabetes undertook an 11 week running program, 3 times per week- a low volume HIT consisting of:10 x 1 min with 1 minute recovery at 9.5/10 effort which was a total workout time 25 minutes compared with moderate intensity continuous training of 45 minutes cycling 3 times per week at 5/10 effort. The results of the study showed low volume HIT showed greater improvements in fitness than the moderate intensity interval training group. Only low volume HIT led to reduced blood glucose, insulin resistance and reduction in visceral fat.
Bottom line is that:
Shorter more intense workouts (Low volume HIT) are very time effective and lead to equal or greater increases in fitness and improvements in cardiometabolic risk factors (blood glucose, insulin resistance and blood pressure) compared with high volume moderate intensity continuous training
High volume moderate intensity continuous training seems to be a more effective way of reducing body weight and waist circumference however there is evidence low volume HIT can also reduce body fat!