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High intensity interval training workouts, or HIIT sessions as they are commonly called, involve short bursts of high intensity exercise followed by a short period of rest or active recovery. They include both aerobic exercise and strength training in the same session, and usually only last between 10 and 30 minutes, but can produce health benefits similar to twice as much moderate-intensity exercise.

What are the health benefits of HIIT?
A study published in the ACSM Health & Fitness Journal presented encouraging results in relation to cardiometabolic and brain health.

The research suggested that interval training had benefits for brain health in both healthy and clinical populations, including those at risk from or diagnosed with chronic diseases that affect neurological function such as Stroke, Parkinson’s Disease and ADHD.  HIIT in clinical populations also showed enhancements in motor function, learning, memory and attention.

HITT has also been shown to improve:

  • abdominal fat and body weight while maintaining muscle mass
  • cardiovascular health
  • blood pressure
  • insulin sensitivity
  • cholesterol profiles
  • aerobic and anaerobic fitness

Another interesting HIIT study carried out by ACSM was in relation to obesity and its link to multiple diseases, including postmenopausal breast cancer and the feasibility of HIIT to help treat people in this high-risk population. The study concluded that HIIT is feasible, safe, and seems to promote greater improvements in cardiorespiratory fitness compared with moderate intensity continues training (running, swimming etc.) and usual care in women at high risk for breast cancer.

Why is HIIT so Popular?
HIIT workouts tend to burn more calories than traditional workouts, even after the workout has finished. This post-exercise period is called “EPOC” which stands for excess post-exercise oxygen consumption. This is where the body is continuing to use energy to restore itself to pre-exercise levels and can add up to 15% more calories to the overall workout energy expenditure. A study has also shown that HIIT was found to shift the body’s metabolism toward using fat for energy rather than carbs. As many people enjoy the weight control benefits of exercise, this additional post-exercise calorie burn is a welcome side effect!

A big problem many people complain about when exercising is that they get bored of doing the same thing over and over. Lots of different exercises are incorporated into HIIT sessions such as such as cycling, free weights, HIT Machines, resistance training etc. which helps to keep people interested.

HIIT training can also be modified for people of different fitness levels and for various conditions such as for those with diabetes or who are overweight. This means it is an accessible form of exercise for almost anyone.

Possibly one of the main reasons so many people are taking up HIIT is the short length of the sessions. We all have busy lives and being able reduce exercise to a quick 25 minutes, but still see results as if we were training much longer has got to be a win win for everybody.  It means we can take care of our health and fitness, but still have time to spend with our family, friends and other interests.

Links for further reading

Healthline Benefits of HIIT
ACSM Brochure on HIIT
MSSE Study HIIT Is Feasible in Women at High Risk for Breast Cancer
PubMed Is HIIT effective in improving cardiometabolic rate in overweight and obese youth