February 01, 2023

Why do we feel SO good after a HIIT workout?

Ever wondered about the true health benefits of High Intensity Interval Training (HIIT), or why we feel SO good after a seriously sweaty session?

Well, we’re about to break down the science for you. The experts at Upwell Health Collective, and its Head of Exercise Physiology, Jaclyn Murphy, is here to answer all our burning questions.

Over to you, Jaclyn!

1. Can you please expand on the science behind why you feel good after a high intensity workout?

It is widely reported and commonly known that exercise in general can improve our mental health and sense of wellbeing, however it has also been extensively reported that high intensity workouts increase the release of endorphins, our feel good hormones.

Endorphins are a group of neurotransmitters or chemical messengers, such as dopamine, serotonin, norepinephrine and GABA, that carry signals from one neuron to another nerve cell or muscle. Endorphins in particular increase feelings of wellness, happiness and wellbeing and decrease or dampen pain signals within the body. Our brains are like our natural medicine chest.

Further high intensity workouts increase performance of the prefrontal cortex (responsible for cognition) in response to an acute bout of exercise leading to increased concentration and focus and feelings of being in control of our emotions and reactions.

Physiologically, as fitness increases high intensity exercise can lead to better oxygen uptake and increased cardiovascular fitness, meaning that the body becomes more efficient at transporting oxygen to working muscles, organs and brain. This leads to feelings of clarity, reduced brain fog, improved concentration and elevated mood.

2. What is the ideal timeframe for a HIIT style workout to get those endorphins flowing – is 15-20 minutes a good amount?

As little as 5 minutes of anaerobic or high intensity exercise can have significant mood boosting effects, however, the physical activity guidelines recommend approximately 150mins per week of moderate to vigorous physical activity, which equates to about 21 minutes per day.

3. Would you recommend summertime / warmer weather a good time to get back into HIIT workouts? i.e. lighter in the mornings and at night time etc., generally people have more energy?

Summer is a great time for people to get back into the swing of high intensity workouts, the weather is warmer and the days are longer. We also generally see an increase in everyone’s mood and energy levels with more daylight hours, so incorporating just a 20 minute HIIT workout each day during the summer has multiple benefits.

Top tips for summer workouts!


  • Be sure to increase your hydration as you will sweat more in the summer;
  • Summer is also a great time to add electrolytes to your hydration as it will help to maintain your sweat loss balance;
  • Wear breathable and light activewear (eg: Jaggad) to stay cool;
  • Be sunsmart to regulate your body temperature and stay cool (eg: exercise in the shade, wear a hat and of course sun protection.).