Dossier: Stress and relaxation

How relaxation strengthens your immune system

Chronic stress is harmful for the immune system. How can we strengthen our body’s defences? Often it’s a good idea to simply do less.

Text: Stefan Schweiger; photo: iStock

If we had to draw a picture of our immune system, we’d probably think of thick walls and protective shields. This image isn’t entirely wrong, because our immune system does prevent invaders such as viruses, bacteria, fungi and parasites from penetrating deeper into the body and causing disease. Defence cells with very different tasks are found throughout the body, waiting to be deployed. Some specialise in detecting and marking pathogens, while others release signalling substances and summon further defence cells to join the fight.

If we take a closer look, however, comparing our immune system to a wall-like fortress is too simplistic, because it isn’t a massive, static structure at all. Instead, it’s a flexible and complex network of cells, tissue and organs. And, as research increasingly shows, it is closely interwoven with the psyche. In fact, they both even speak the same language. Findings from recent years show that nerve cells and immune cells communicate with each other via the same receptors.

Stress response: a useful evolutionary reaction with a catch

A simple example of how the stress mechanism works is our body’s reaction to a perceived danger – while driving, doing sport or, once upon a time, stalking through the bushes as a hunter-gatherer: our pupils dilate, our heart beats faster and our breathing accelerates. Among other things, the stress hormone cortisol is released to boost the body’s performance in the short term. The immune system also kicks in to prepare the body to repair the damage: white blood cells are mobilised faster and the production of immune cells is stimulated.

In the short term, this is a useful mechanism that is essential for survival. But “short term” is the key word here. Long-term stress causes the immune system to crash and the production of immune cells drops off again. People who are under permanent stress are more likely to fall ill and their recovery will be slower.

Positive thoughts are good for the immune system

But there’s good news, because this body-mind mechanism also works with positive thoughts. Studies show, for example, that a positive attitude affects how the body responds to vaccines. So, what and how we think, do or consciously don’t do has an impact on the body’s defences in the form of restorative routines. The mechanisms of the immune system and nervous system can be harmonised. You just have to do it.

Five tips for a relaxed immune system

The following five tips will help you manage stress. Your body’s immune system will thank you.

Manage stress

It’s not always possible to avoid stress in our daily lives, but we can handle it differently. The first step is to create a clear boundary between your professional and private lives. Next, you have to set priorities and stick to them, e.g. by drawing up lists.

Create positive experiences

Switching off and relaxing doesn’t mean you have to lie around idly on the sofa. Fresh air and getting outdoors do you good. A forest is an ideal place to take deep breaths while on a walk.

Try relaxation techniques

Whether it’s breathing meditation, mindfulness, autogenic training, yoga or progressive muscle relaxation, with a little practice it gets easier to relax the muscles, lower blood pressure and stop the thoughts from whizzing through your brain. Just try it out! With your partner, in a course or with the support of an app.

Take breaks

If you want to bring your A-game, both your body and mind need periods of recovery. Take time out for yourself. This might be something as simple as having a cup of tea, listening to your favourite song or doing a breathing exercise. Taking many short breaks is better than one long one.

A good night’s sleep

While we sleep, our body is active. It uses the quiet time to stimulate repair processes. The immune system’s T-cells are particularly active during this time. How much sleep do we need? Sleep requirements differ from person to person, but on average we should get around seven to eight hours of sleep a night.

Causes and symptoms of a weak immune system

If the immune system is permanently weakened, symptoms include constant fatigue, weariness and an increased susceptibility to infections. This often leads to colds and flu-like infections, but may also result in gum disease or other inflammations. The wound healing process may also be affected. Taking a long time to recover from an infection can also be a sign that the body’s immune system is weak.

This may be caused by an underlying illness, such as diabetes mellitus, kidney insufficiency or HIV. In addition to constant stress, a weak immune system can also be caused by an unhealthy lifestyle, because this usually goes hand in hand with a lack of sleep, nutrients and/or exercise.

Why children and senior citizens suffer more frequently from infections

Age also comes into play. While children’s immune systems first have to build up – they’re not yet fully developed in infants and have to be trained for years – their resistance declines again in old age. The body produces fewer immune cells at this stage of life and immune reactions slow down. This is why children and older people suffer from infections more often. It’s therefore all the more important that both groups take advantage of the recommended vaccinations. For example, the flu vaccination is recommended for senior citizens.

Exercise, stress and nutrients

The good news is that your immune system benefits from a healthy lifestyle no matter what your age. There’s no miracle pill or universal home remedy, but regular exercise and sufficient sleep are proven to help. And you don’t have to overdo your training. In fact, exercising too hard can even have a detrimental effect on your immune system.

When it comes to nutrition, it’s not about getting one specific nutrient, such as vitamin C, but rather eating a varied and balanced diet. You should eat the rainbow! If you buy a colourful array of fruit and vegetables when you’re out shopping, you’re on the right track to getting all the vitamins, minerals and plant-based protein that you need.

“Remobilise your power reserves”

Zurich-based psychiatrist Flurin Cathomas is investigating how closely the immune system and the brain are connected. He explains how relaxation exercises affect the immune system and what side effects they can have.

What’s the clearest sign of the interaction between the body’s defences and the psyche?
Anyone who has had the flu knows how it can affect your mood, spoil your appetite or disrupt your sleep. For a long time, it was assumed that the brain was an organ sealed off from the immune system by a blood/brain barrier. But we now know that there are many communication pathways between the nervous system and the immune system – and vice versa. These interactions are important for maintaining many physiological functions. But it’s also becoming clearer that these neuroimmune interactions play a crucial role in the development of many illnesses. Prolonged stress can lead to chronic changes in the immune system and, accordingly, many stress-related illnesses such as depression are associated with increased inflammation levels in the blood.

Conversely, what effect do relaxation techniques have on the immune system?
Put simply, you can picture it like this: the equilibrium between activation and relaxation is controlled by the autonomic nervous system. When we are tense, the sympathetic nervous system and its neurotransmitter – (nor)adrenaline – are particularly active. When we relax, the parasympathetic nervous system and its neurotransmitter acetylcholine dominate. The aim of many relaxation techniques is to first shift the balance towards the parasympathetic nervous system in order to create a balance again at the end of the relaxation exercise. From this central position, it’s then possible to remobilise your power reserves. The sympathetic nervous system tends to have an inflammatory effect; when it is acutely activated, messenger substances and immune cells in the blood are increased. The parasympathetic nervous system has an anti-inflammatory effect.

Do relaxation techniques also have side effects?
If the parasympathetic nervous system is activated too quickly or too strongly, this can also have negative consequences. Some people doing relaxation techniques for the first time may suffer a negative physical reaction. So it’s best to start in a course under the guidance of a coach. Many good apps are also available nowadays. It’s important to find out what suits you best – and that’s a process that can take a bit of time. If you’re recovering from a mental illness, you should have achieved a certain level of stability before starting. Recommending relaxation therapy to someone who has just experienced a severe depressive episode or an acute psychotic episode may even exacerbate the illness.

About the expert

Private lecturer Dr Flurin Cathomas is chief consultant and researcher at the Psychiatric University Hospital Zurich. Together with colleagues, he recently published a study in the renowned journal “Nature” demonstrating how, over the long term, chronic stress changes not only the immune system but also the brain.  

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