Physiology

Did you ever face a doberman and you were not sure whether he is going to eat you? You felt your heart pounding? Or were you ever trapped in a traffic jam on the way to the airport, and no way to get there in time? I guess you felt the effects of stress hormones in your life. What are these hormones, and what are they doing in your life?

Biologically, stress is a healthy and normal response to any ‘stressor’. The purpose of stress is to prime our body for action in the face of a physical threat. This is called the “fight or flight” response. If you sit in your living room and a tiger walks in the door, how do you react? Well, your brain and your body needs to work overtime, to figure out an escape route for flight, or get prepared for a fight, and either way you definitely will need some extra energy for that. At this moment, the body releases a number of hormones such as adrenaline, norepinephrine, dopamine and cortisol. These chemicals in turn trigger our bodies to reduce our routine functions (such as our immunity and digestive system) and direct the blood to our brains and muscles. Meanwhile, the neurotransmitters will increase focus, awareness and bring on feelings of anxiety and perception of danger. Our heart rates also increase and ultimately, we end up far more on-edge and ‘wired’. Even our feeling of pain is reduced and our blood thickens to encourage clotting in case of injury. All this is involved in what we know as the ‘fight or flight’ response.

Adrenaline, along with norepinephrine are the hormones which are largely responsible for the immediate reactions we feel when stressed. Imagine you’re trying to change lanes in your car. Suddenly, from your blind spot, comes a car racing at high speed. You return to your original lane and your heart is pounding. Your muscles are tense, you’re breathing faster, you may start sweating. That’s adrenaline.

Cortisol and Chronic Stress

Cortisol on the other hand takes a few minutes to kick in, and helps to maintain a healthy balance while you are resolving your stress mission. One major function is providing energy by stimulating several catabolic reactions, that are transforming protein and fat into energy. It controls the release or action of a number of other hormones, and this way helps to maintain fluid balance and blood pressure, while regulating some body functions that aren’t crucial in the moment, like reproductive drive, immunity, digestion and growth. Some effects of cortisol can last even a couple of days.

Today’s stressors are normally not the tiger walking in the door, but an argument with a friend or bills that need to be paid will still trigger that same stress response. And anything that our mind perceives as a threat will be a stressor, like angry bosses, empty bank accounts, upset partners, deadlines at work, and public speaking appointments.

And this is where the problem comes in. The body´s stress response is very adequate for an acute physical stressor, because it allows us to run faster, to spot danger, and to fight when needed. Once the danger goes away, our parasympathetic nervous system would kick in putting us back into the ‘rest and digest’ state, and our body would recover.

But when your stressor is something chronic and abstract, like the conflicts in your team, or the debt that doesn’t just go away, it means you’re constantly in an alert state, with a constantly elevated level of cortisol. Too much cortisol can suppress the immune system, increase blood pressure and sugar, decrease libido, produce acne, cause learning difficulties, lapse of memory, loss of muscle mass, increased obesity and much more.

When we reach a point of continuous chronic stress, the glands producing all those secondary hormones are now going on strike, leading to a condition called glucocorticoid resistance. That means cortisol remains to be elevated, but our cortisol receptors and hormone glands become overwhelmed and resistant to its effects. As a result, the stress recuperation is not taking place anymore.

Cortisol and Immunity

One major problem of cortisol resistance is the depression of the immune system.A particular research study published in the Proceedings of the National Academy of Sciences¹⁾Sheldon Cohen et.al. Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. Proc Natl Acad Sci U S A. 2012 Apr 17;109(16):5995-9. had two objectives.

The first one was to determine whether stress can cause cortisol resistance while the second objective was to determine whether cortisol resistance increases a person’s risk of acquiring an infection such as a common cold. 

The study had 276 healthy volunteers whose levels of stress, BMI, race, age, sex and glucocorticoid resistance were thoroughly assessed at the start of the research.

The volunteers were exposed to rhinovirus (i.e. the kind of virus that causes common colds), quarantined and observed for five days.

At the end of the study, researchers found that those volunteers who had recent exposure to an event that contributes to long-term stress developed glucocorticoid resistance which also put them at higher risk of developing a common cold.

Another study was conducted which was aimed at determining whether cortisol resistance could cause increased levels of inflammation. This time 79 volunteers had virus exposure and were monitored for five days. The results showed that those volunteers who were found to have glucocorticoid resistance had more proinflammatory cytokines, which promote systemic inflammation. Chronic stress definitely puts your immune system at risk.

Controlling Cortisol Levels

We see that reducing cortisol level will be an important goal in stress control. Now we can take a two-pronged approach to reducing cortisol levels:

• Firstly – by reducing the stress that is the root cause of the problem, either by eliminating the stressors, or by improving the ability to cope with them. A reduced emotional response to any stressor will mean a reduced chemical reaction and less cortisol release.
• Secondly – there are known lifestyle and dietary ‘hacks’ that assist the mind and body to reduce the release of cortisol into the system. Exercise, sleep, a light nutrition with lots of vitamin C and Omega 3 are some of the factors that can help reduce cortisol. Some bad habits can though increase cortisol production, like the consumption of caffeine, alcohol or an excessive amount of sugar.

Key is to learn how to deal effectively with chronic stress, which is responsible for high cortisol levels. If you want some more practical tips on how to effectively deal with stressors, and which lifestyle factors can help you reduce cortisol, get The 10 Minute Guide to Stress Management.