Georgia Holliday Coaching

Is HIIT actually good for us?

In the last couple of years, every FiTnEsS person has been posting HIIT workouts on their Instagram feed (myself included). But is HIIT actually beneficial for us?

Yes and no.....bare with me!

Whilst I believe HIIT is a genuinely great, time efficient way to work out, burn calories and improve cardiovascular fitness, I also want you to appreciate that it is a very high stress form of exercise and isn't suitable for everyone.

To put it simply, when we exercise, our bodies produce the hormone cortisol (also known as the stress hormone) which puts the body into fight or flight mode. Although this hormone tends to get a lot of bad press it isn’t all bad. Short term bursts of cortisol are necessary to help us recover from the effects of stress and keep us focused on survival. So we actually need a little bit of cortisol to function optimally (which means we thrive best with a little stress in our lives).

However, I personally believe we are living in a day and age where more often than not, we are functioning in this high stress/fight or flight mode (I know I certainly am which is why I am sharing this with you in case you can relate). This stress we experience, can be caused by high pressure jobs, alcohol consumption, busy lifestyles, relationship problems and the ever growing stimulation we are exposed to through technology (social media, television, video games etc.) A lot of these things cause stress and subsequently, the cortisol level in the brain to rise. Even something as small as getting irritated when you're stuck in traffic can trigger the brain to think you are in danger and therefore sends you into fight or flight mode (enter excess cortisol). The thing is the brain often can't tell the difference between emotional stress and physical stress (i.e. life threatening danger). If we don't diffuse this stress regularly (through relaxation and allowing ourselves to unwind) then we will forever be in this unhealthy state. If we then add multiple HIIT sessions into the mix, we are further stressing the body and central nervous system. This is why I only ever advise and prescribe two HIIT sessions a week (maximum) to my clients.

So, what are the effects of a consistent high stress level?

Now, I tell you this from personal experience, although it may seem glamorous to constantly be go-go-go, it absolutely is not! I have learnt first-hand the negative mental and physical effects high cortisol can have on the body. Below are just a few...


Adrenal fatigue


Poor sleep quality


Low immune system

Lack of focus

Lack of interest

Lack of motivation

Weight gain

Muscle tension/more prone to injuries



Panic attacks

Carbohydrate cravings

Reduced/increased appetite

Raised blood pressure

Reduced libido

Depression/low mood So how should I workout if I am under a lot of stress?

We know that exercise is great for our health but it also has amazing benefits for our mental health (including reducing stress). The trick is, to learn which type of exercise suits you best at any given time. If you have had a super stressful day at work and then gone home and had an argument with your other half, odds are you are a ginormous ball of stress. In this case adding the extra stress of a HIIT workout probably isn't the most sensible thing to do. Maybe try a long walk or a less intense class or workout at the gym instead. This way you are moving that anxious energy but not overloading the body with stress. If you know you're an absolute stress pot as well then give this low impact leg workout a go and let me know what you think. It will still get you sweating and burning but without the extra stress on your body! 1. Squat to Curtsy Lunge. 2. Double Pulse Squat. 3. Reverse Lunges. 4. Standing Side Leg Lifts. 5. Wall Squat. 6. Sumo Squat with Heel Lifts. 7. Demi Plies.

Click here for video demonstrations of each exercise. I hope this resonates with some of you and can help you understand the effects of stress and exercise on the body a little more.

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Love Georgia xx