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  • Writer's pictureJessica Kanerva

Stress and its implications on our immune system

Updated: Jun 20, 2020

It is widely known and recognised today that prolonged stress can have negative effects on health. There are many ways in which long-term stress can cause health problems, one being its effect on our immune system.

In this post I discuss how stress affects our immunity and I also offer a few simple ideas and tips on what we can all do to lower our total stress load.

It is safe to say that we live in uncertain times, where high levels of stress have become the norm for many of us. With the current COVID-19 pandemic and the uncertainty of our future, it is hard not to experience a rise in our stress levels.

There is a major focus at the moment on immunity and its importance, both in protecting, as well as fighting off illnesses such as COVID-19. I have received many questions from people, asking about what to do in order to be better prepared for, and in preventing catching COVID-19. In this post I will give some background details on the human stress response and how it may affect our immunity plus a few things which we can do ourselves to help lower our stress load. We might not be able to directly alter the situation we are in,- but how we react and respond to it can be an important factor for our personal, physical and mental health and wellbeing.

Stress and the immune system

We have all probably heard about the human stress response and how stress, when prolonged, can have a negative effect on our health.

Our innate and acute stress response has throughout history (and still to this day) helped save us from danger. The release of stress hormones such as for example, cortisol and adrenaline from the adrenal glands, has a direct effect on our mental clarity, focus and alertness and create a cascade of mechanisms which all have the one main goal, to help protect and keep us alive in moments of danger.

This stress response causes our blood pressure and heart rate to increase, moving oxygenated blood quickly to the areas of the body it is most required. Glycogen which has been stored is released as glucose, to fuel our brain and muscles, thus increasing our blood sugar levels. Non-essential (at the time) functions and mechanisms are not prioritised at this time (these include digestion and balancing sex hormones as the body won’t focus on digesting that dinner or supporting fertility when you may potentially be in a situation of life-threatening danger!).

This stress response, as mentioned, is crucial for survival, and in an acute stress situation, our immunity actually increases to protect the body from potential infections as cortisol by nature has an anti-inflammatory role.

However, when stress is prolonged, it begin causing havoc with our health in many ways, as our immune system can begin to become "resistant" to the high levels of cortisol and corticosteroids (1), which can result in the anti-inflammatory effects of cortisol being impaired, thus opening the door to inflammation and resulting in a declined immunity (2). Prolonged stress has also been shown to lower the number of natural killer (NK) cells as well as T-lymphocytes, white blood cells which all help protect our cells and kill off viruses and bacteria and this can have a negative effect on our immune system (3). Research has also shown that the amount of stress exposure is linked to the level of decrease in immunity, with a higher dose of stress resulting in a more profound weakening of the immune system. It has also been shown that as we age we get less resilient to the effects of stress. Therefore, it is important to implement stress reduction techniques as we age (4). The human body cannot distinguish between a sable tooth tiger and a work deadline. Therefore, constantly being exposed to stressors as a part of our daily lives, we can start to the negative effects of chronic stress on our health.

At times like these when we are facing threats, both in terms of our health and our financial future, the effects of stress are likely to increase the stress load we are under. It can be daunting reading about the negative impacts of long term stress when we are constantly faced with stressors as part of our daily lives and this is heightened even more when living through a pandemic.

So how do we find calm in unprecedented times? Managing stress is today more important than ever to stay healthy.

The good news is that there are many areas we can look at ourselves to help our bodies cope better and lower our total stress load

We may not be able to directly control what is going on around us but at times like these when we may feel lost and worried, it is more important than ever to focus on what we, ourselves can do to feel better, both physically and mentally and to feel more empowered.

Listed below are a few areas which we can look at ourselves to help lower the total stress load.

This list is in no way exhaustive and there are many more areas in which we can address stress, but these are a few which I find very useful, both personally and in practice.

We might not be able to take away the situation we are in, but how we react and respond to it can be a massive factor for our health and wellbeing.

1. Sleep

Many of us have been forced to slow down over the past few weeks and not been able to go to work and school and we therefore may have more time to fit in those recommended 6-8 hours of sleep. Not sleeping enough is detrimental to health and more and more high quality research, shows a strong correlation between inadequate or low quality sleep and health problems. The stress hormone cortisol and the sleep hormone melatonin work in a fine balance 24/7. When we wake up in the morning- cortisol is expected to peak shortly after waking to help us get going with the day. Then it gradually decreases throughout the day to be lower in the evening when melatonin should increase to help us go to sleep. Feeling stressed will affect this balance and can cause sleep disturbances and make it harder for us to sleep. To promote better sleep, it is important to create a good sleep hygiene routine. This can include turning off electronics (ideally a couple of hours before going to bed), avoiding heavy meals close to bedtime, avoiding alcohol and also avoiding drinks loaded with caffeine, such as coffee, after midday.

2. Eat the rainbow

We‘ve all heard the phrase “eat the rainbow” and it really is true, eating a wide variety of vegetables and fruits (more heavy on the veg) will help immunity by providing us with important minerals, vitamins and phytonutrients which are important for our bodies to deal with stress and to function well. Try choosing foods low in sugar and refined carbohydrates to maintain more balanced blood sugar levels throughout the day as high sugar foods cause a rollercoaster effect on our blood sugar, which in turn affects the release of stress hormones and insulin levels and can negatively affect our immunity. When possible choose whole foods rather than processed and refined, high sugar foods, both for the nutrient density and lower sugar content.

3. Breathing

It is something we do automatically since birth and something we don’t really think about, but breathing has an incredibly powerful impact on our health in all aspects. When we are stressed our breathing changes both in pattern and rate and by incorporating deep breathing, we can naturally help lower the body's stress response- slowing down our heart rate and lowering blood pressure and cortisol levels. If you are feeling stressed and overwhelmed trying simple breathing techniques can make a huge difference. Personally I really like the work of Richie Bostock ( He has a wealth of knowledge and teaches simple ways to help people breath better.

4. Decreasing alcohol

I am sorry to say it, but alcohol acts as a stressor to our bodies. Although we often feel relaxed after a drink or two, alcohol still affects our stress response, depletes nutrients and also interferes with our quality of sleep, which, as mentioned is essential for our stress response and immunity. NHS recommends drinking no more than 14 units of alcohol per week on a regular basis (equivalent to 10 small glasses of wine per week) for adult men and women (not applicable to pregnant or breastfeeding women) (5). However less is always better and if you do consume alcohol try to spread out the drinks over the week rather than binge drinking and do incorporate days in the week when you don't drink any alcohol at all.

5. Movement

We all know that we should be exercising on a regular basis and that keeping fit is good both for our physical and mental health. The NHS in the UK recommends incorporating at least 150 minutes of moderate, or 75 minutes of vigorous exercise per week (6). It is important to keep in mind that exercise in itself is a stressor to the human body and that too much exercise can cause harm. Research has shown that too much strenuous exercise can drain our adrenals and negate our stress response and furthermore have a negative impact upon our immune system. For someone who has been under a lot of stress for a long time, exercising too much can drain the adrenal glands even further. Some people therefore benefit from doing more gentle types of exercise instead of intense training and it is important to look at each individual when recommending exercise. I find however, that as a rule of thumb for most people is to try and achieve around 20-30 minutes of light to moderate levels of exercise per day. It is also imperative to take breaks when sitting for prolonged periods of time by doing some simple stretches and movements. It is just as much about how much we are sitting still as it is about our exercise regime! Yoga and pilates are great forms of exercise which are gentle on the body and also helps lower stress and there are many free exercise guides and videos online.

6. Connection

Loneliness and social isolation is today a widespread health issue amongst adults (and children) and can have serious detrimental impacts, both on our physical and mental wellbeing. Loneliness has been shown in research to be as equally negative to health as smoking 15 cigarettes per day and it also has the ability to increase our risk of death by between 26% and 45% (7). With the COVID-19 pandemic affecting how we socialise and interact it is more important than ever to stay in touch with people around us and to check in with our friends and family. Technology and social media often get a bad reputation but in times like these we can really take advantage of such modern technology and stay connected with friends and family online. Make sure to reach out to people around you and, if you feel lonely, consider joining an online course where you can find like-minded people to interact with. It is incredible what a difference it can make to your health when you know someone's got your back! Being able to talk to someone and feeling like you are not alone really can help lower stress levels by calming us down, improving how we cope in stressful situations and improving our general wellbeing.

Don’t be too hard on yourself

We are all human and we will all have days when life feels hard and we lack motivation and don’t manage to sleep enough, eat as well as we would like to or do any exercise. Don’t beat yourself up about it, having a regular routine and eating healthily, and exercising most days is great, but keep in mind that being too strict and rigid about what you can and cannot do is not healthy either. Be mindful of how you feel, mentally and physically and try and treat yourself the way you treat the people you love, with respect and care and accept that we will be experiencing different feelings and emotions from day to day.

Keeping calm and healthy during a pandemic is not easy but I do hope that some of the information given will be of use to you and will help you stay healthier and happier in the times ahead!

Stay safe and healthy




Sleep hygiene and meditation:


Food and vegetable boxes (London & UK)


Please note that the information in this article is for educational purposes only and is not intended to diagnose, treat or cure any disease. The information given is not exhaustive or prescriptive and is not intended to be used as medical advice or as a substitution for medical care. Health and wellness is individual and if you have any health concerns make sure to contact a registered and qualified health practitioner, suitable for your specific needs.


1. Schneiderman, N., Mccabe, P., S. Baum, A. (2018)

Psychology Press, 24 Oct 2018 - Psychology - 328 pages

2. Yong-Soo, B., Eui-Cheol, S., Yoe-Sik, B., Van Eden, W. (2019) Stress and Immunity. Frontiers in Immunology vol 10. 2019. doi.10.3389/fimmu.2019.00245

3. Maydych, V., Claus, M., Dychus, N., Ebel, M., Damaschke, J., Diestel, S., Wolf, O. T., Kleinsorge, T., & Watzl, C. (2017). Impact of chronic and acute academic stress on lymphocyte subsets and monocyte function.PloS one,12(11), e0188108.

4. Morey, J. Boggero, N., Scott, I.A., A. B., & Segerstrom, S. C. (2015). Current Directions in Stress and Human Immune Function.Current opinion in psychology,5, 13–17.

5. NHS (online) (2018) Alcohol units. Available at

6. NHS (online) (2019) Exercise. Available at

7. Holt-Lunstad, J., Smith, T.B., Layton, J.B. (2015) Social relationships and motality risk: a meta-analytic review.



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