Stress, hormones & health

Cortisol is a hormone released by the body in response to trauma, fear, stress (both physical and mental), infection and illness. It signals to the body that more energy is needed (in the form of sugar) to combat these challenging situations. So it is an essential hormone in the human body that helps to keep us alive and healthy. However, like most things, when we have too much of it, it can cause problems.

Chronic high levels of cortisol affect the immune system response while at the same time suppressing the digestive system, the reproductive system and growth processes. The change in the natural cortisol feedback system also affects the regions of the brain controlling mood, motivation and fear. In addition, raised cortisol levels are also linked with weight gain (particularly around the middle) and heart disease. It’s not all bad news though. There are many ways to manage cortisol levels.

Relaxation techniques

Practising relaxation techniques such as those used in yoga, Pilates or meditation classes can help, as can taking part in regular low intensity exercise such as walking or swimming. In fact studies have found that practising yoga or meditation on a regular basis can reduce cortisol levels by around 20%.


There are also changes you can make to your diet to reduce the spikes in cortisol. Caffeine, alcohol, sugar and refined carbohydrates such as cakes, biscuits, white bread and white pasta all lead to raised cortisol levels. If you have these each day, you can imagine the effect it will have.

Certain foods can actually lower cortisol levels. For example, studies have found that the fats found in oily fish (salmon, mackerel, sardines, trout, and anchovies) help to reduce cortisol levels – aim for two to three portions per week, and if you struggle with this, consider taking an omega 3 supplement.  Interestingly, despite being caffeinated, black tea may also lower levels of cortisol.


In addition to a healthy diet, sleep is key when it comes to controlling cortisol levels – a study in a group of pilots found that when they slept for six hours or less per night for seven days, their cortisol levels increased significantly and stayed elevated for over two days.

So the next time you’re feeling stressed, overworked or perhaps aren’t looking after your body, think about what’s actually going on inside, and what damage this could cause long term. Taking simple steps today can help to reduce this damage.

Written by Ruth Tongue

(MSc Nutrition)

Samel, A, Vejvoda, M & Maaß, H. Sleep Deficit and Stress Hormones in Helicopter Pilots on 7-Day Duty for Emergency Medical Services. Aviation, Space, and Environmental Medicine. 2004, 75(11).