Short bursts of vigorous exercise from several seconds to minutes can be very beneficial to fitness and health. This latest ‘word on the street’ is supported by science-based studies over the last decade and is now incorporated into updated physical activity guidelines worldwide such as the 2018 US Physical Activity Guidelines for Americans. Short bursts of vigorous exercise can be a great ‘bang for the buck’ when considering time is short in a busy day and for many who find it difficult to fit in the recommended 30 minutes of moderate intensity exercise for the day.  If exercise is vigorous, it is now recommended that only 75 minutes per week is needed for fitness and health.  So what is vigorous activity, and how does it relate to the new trend of ‘high-intensity interval training’?


High-intensity interval training (HIIT) was named the #1 Fitness Trend in 2018.  It involves brief bursts of vigorous or intense exercise, that last a few seconds to several minutes and is interspersed with brief periods of low activity or rest. The key for optimal benefit, is the short bursts of exercise need to be vigorous or high intensity, so that you are exercising at or above ~80% of your maximal effort.  What this means is that on scale of 0-10 in effort (0 = no effort and 10 = maximal effort) you need to be at about 8 or above.  Examples can include a 5-minute workout involving sets of calisthenics type exercises (e.g.  sit ups, chair rising, air squats interspersed with a short break) or hard walking, running or cycling. HIIT can be a very time efficient approach to getting the required activity needed to gain fitness and health. HIIT typically results in increased strength, muscle endurance and has benefits for your cardiovascular system among others benefits and adaptations in the body.

If you haven’t done so before, why don’t you try some shorter bursts of more intense exercise to change up longer bouts of moderate intensity? Of course, the best exercise regimes are the ones you will do over many years.  The key for you is to work out what works best to keep the exercise habit going for years to come.  Knowing the benefits of short intervals of exercise that are time efficient can be helpful to fit in the exercise you need, especially if done in combination with longer sessions of activity over a week!



Gibala, M. J. and J. P. Little (2020). “Physiological basis of brief vigorous exercise to improve health.” Journal of Physiology [London]. In press.

Stamatakis, E., et al. (2019). “Short and sporadic bouts in the 2018 US physical activity guidelines: is high-intensity incidental physical activity the new HIIT?” British Journal of Sports Medicine 53(18): 1137-1139.

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