Cortisol Consciousness

Intensity is the key to results. Go hard or go home. Sound familiar? It should be if you arbitrarily make ‘intensity’ the measure of fitness by which you judge yourself and others. However, could it be that training with all out intensity could actually be making you unwell?


In a world where the lines between general health and sports performance are so blurred that everyone now refers to themselves as an ‘athlete’, maybe. It’s all about intent. If your intent is to resist the ageing process and gain greater health and freedom, then it may very well be that training ‘hard’ day in and day out could be moving health markers further towards ‘sickness’. It’s down to a tiny group of molecules called the cortisol hormone.


Cortisol is produced mainly in the adrenal gland. It is released as a response to stress and low blood glucose.

It can lead to several effects on the body:

Decreased muscle mass due to an effect called proteolysis

Increased body fat due to an effect called lipolysis (represses this)

Reduced bone formation (problematic if our goal is to reverse the ageing effect on bones)

Down regulation of collagen (leading to tendon issues)

Decreased sensitivity to amino acids (the building blocks of muscle)

Impaired learning by damaging to the cells in the hippocampus

Decreased cellular repair via immune system changes at a cellular level

Lower body mass indexes in babies born to mothers with high cortisol and other effects on the child in the womb

Type 2 Diabetes


As you can see, there are MANY negative effects of having high cortisol levels. These are just a few of the myriad of side effects.

HIIT training (see citation link at the end of the article) has been shown in studies to increase cortisol levels. Cortisol is also released in competitive environments and loud environments. Now lets consider a typical group class environment. Loud music, anxiety of competing against other class members, usage of blood glucose during the workout. Add this to the fact that many clients are attending the gym to try to deload from ALREADY stressful lives and you can see we may have a situation where we are flooding our clients with cortisol.



This has led to a rise in the numbers of gyms I’ve seen in the U.S. that are now offering ‘cortisol conscious’ workouts. The worm is turning (slowly) and many coaches and gym owners are recognising that training for health is vastly different from training for sport. If you have athletes you train, then its going to be advantageous for them to train in this stress environment (sometimes) so they can get used to what that feels like. But if you are training clients for general health, you may want to consider stress hormones as a factor in their program design. How can you do this? Well, consultation and assessment are good starting points to get to know your clients and what their lives look like. Remember that the workouts you prescribe can’t be a band aid for a poor lifestyle. If they dont have good basic lifestyle guidelines in place like sleep, hydration and sunlight exposure, then that has to be encouraged and reflected in the training prescriptions.

Study link:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=16&ved=2ahUKEwj088-Ew87mAhUNZMAKHfgMBTUQFjAPegQICBAC&url=https%3A%2F%2Fwww.mdpi.com%2F2071-1050%2F11%2F21%2F6069%2Fpdf&usg=AOvVaw2MRB55gMMOn5Q02s_12T2S

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