What is High Intensity Interval Training (HIIT)?

HIIT is a type of training involving repeated bouts of high intensity exercise followed by varied periods of lower intensity exercise.

The intense work period may range from 5 seconds to 8 minutes long and are performed at 80-95% of maximal heart rate (HR) while the recovery periods may be equally as long as or longer than the work periods and involve exercise at 40-50% of max HR. You usually alternate work and recovery periods for 20-60 minutes.

HIIT can be any done using mode of exercise – cycling walking, running, swimming, cross—training or in group exercise classes.


Who can do HIIT?

Most people!

HIIT has been shown to be safe and effective in a wide range of patient groups including older adults, type 1 and type 2 diabetes, paraplegics, intermittent claudication, COPD, cardiac rehab patients


Benefits of HIIT for weight loss and metabolic syndrome

Provide similar fitness benefits as continuous endurance workouts, but in shorter periods of time. HIIT burns more calories than traditional workouts both during and after exercise.

  • Improved aerobic (increased VO2 max) and anaerobic capacity
  • Blood pressure
  • Cardiovascular health
  • Improves insulin sensitivity (which helps the exercising muscles more readily use glucose for fuel to make energy)
  • Decreased fasting insulin
  • Cholesterol profiles
  • Abdominal fat and body weight while 
maintaining muscle mass – ability to increase whole body fat oxidation
  • Increased mitochondrial capacity
  • Reductions in body fat including subcutaneous fat and abdominal fat
    • Increase exercise and post exercise fat oxidation and decreased post exercise appetite
  • Decreased waist circumference and body mass


The number one reason for not doing exercise is “lack of time.” HIIT gives all the same and maybe more benefits of continuous moderate intensity exercise in a much shorter amount of time.


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Drigny, J., Gremeaux, V., Guiraud, T., Gayda, M. ,et al. (2013). Long-term high-intensity interval training associated with lifestyle modifications improves QT dispersion parameters
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Talanian, J.L., Galloway, S.D., Heigenhauser, G.J., Bonen, A., Spriet, L.L. (2006). Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women. J Appl Physiol, 102, 1439–1447.
Little, J.P., Gillen, J.B., Percival, M.E., Safdar, A., et al. (2011). Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial capacity in patients with type 2 diabetes. J Appl Physiol, 111, 1554–1560.