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The stress hormone cortisol

Work pressures, smart phones, email, long hours, it is harder than ever to switch off and stress seems like just an expected result of normal life.

Work pressures, smart phones, email, long hours, it is harder than ever to switch off and stress seems like just an expected result of normal life.However constant stress can have significant effects on the body in more ways than just craving a glass of wine at the end of the day.


Cortisol is a steroid hormone produced from cholesterol in the adrenal cortex of the adrenal glands located on top of each kidney. It plays a role in most of the body’s functioning’s including regulating blood sugar levels, metabolism, salt/water balance, blood pressure and inflammation.

When we encounter a perceived threat -such as a large dog barking at us - our hypothalamus, a small region at the base of our brain, sets off an alarm system in our body. This then prompts our adrenal glands to release a surge of hormones, including adrenaline and cortisol, that cause the ‘fight-or-flight’ response to prepare us to get out of the dangerous situation. Cortisol, the primary stress hormone, increases sugars (glucose) in the bloodstream, helps our brain use glucose and aids tissue repair.

Cortisol also curbs functions that would be that could be detrimental in a fight-or-flight situation such as the immune and digestive systems, the reproductive system and growth processes. It also affects certain brain functions as well as mood.

For many people though, stress isn’t just an occasional reaction to a threat but rather a daily occurrence as a result of a hectic lifestyle. When stressors are always present, the body’s fight-or-flight response becomes chronic. This is where the problem arises as cortisol is constantly suppressing important functions such as the immune system and this can lead to health problems including anxiety, depression, digestive problems, heart disease, headaches and insomnia. High levels of cortisol can also cause fat to be stored around the organs in the abdomen (visceral fat) which can lead to risk for developing disease such as cardiovascular disease and diabetes. Recent thinking is that high levels of cortisol can also lead to something called Adrenal Fatigue. This is where the adrenal glands become overworked and so produce too little hormones, leading to symptoms such as extreme tiredness and problems focusing.

Stress isn’t just experienced in the brain but also in the body. Another time we produce cortisol is when we exercise, as our body reacts to being put under a certain amount of stress. However, over-exercising or exercising at a very high intensity, such as lifting heavy weights, can cause chronically high levels of cortisol. This then has similar effects on the body as chronic stress and can not only cause health risksbut also hinder the results of exercise by causing the body to hold onto fat around the middle (a side effect of high cortisol levels).

Whether from intense over-exercising or chronic stress, the long-term activation of the stress-response system and therefore raised cortisol levels, can disrupt almost all our body's processes. Acortisol blood testwill tell you the level of cortisol in the blood, however as cortisol levels naturally rise and fall significantly throughout the day, a24-hour urine testmay give a more complete picture of the body’s cortisol levels and can point to a possible chronic stress problem. Repeating the test may also be required to monitor cortisol levels over time.

Get a Cortisol Blood Test here

Get a Cortisol Urine Test here