How Stress Affects Immunity

Posted by Naomi Rohr on

If the pandemic in 2020 taught us anything, it is how important it is to have a strong immune system. It also put a spotlight on mental health and stress—how it had long lasting physical effects. What’s more interesting is that there seems to be a link between chronic stress and a weakened immune function.

Researchers over the years, have made interesting observations between those living hectic, urban lifestyles compared to those living a more relaxed lifestyle in rural areas. For example, researchers have noticed that the incidence of asthma is higher and increases at a higher rate in urban areas than in rural areas. 

This article published on the APA (American Psychological Association) shows just how much stress affects our physical health. It has been linked to problems in our muscles, respiratory tract, digestive system and even the reproductive system. 

Covid-19 and the Mental Health Crisis

In a survey from APA, it was found that almost 80% of Americans found the pandemic to be a significant source of stress in their lives in 2020. 60% of the participants said that the stress caused by the pandemic is overwhelming to them. As the economic fallout after the pandemic is only going to get worse, this mental health crisis won’t be going away anytime soon.

This poses a huge problem, because stress only worsens immune function—at a time when a robust immune system is needed the most.

So, if stress is so bad, then why do humans even have this emotion? 

Stress—the good and bad

Believe it or not, stress actually serves a valuable purpose in the human body. Thousands of years ago, many humans lived their lives on the edge of danger—from animals and predators. 

Stress was needed to create a biological response that prepared the body for danger. It increases the blood supply to your muscles, makes you more alert, your heart beats faster and you breathe faster. All of this is to physically prepare you for a fight. 

However, back then, these stress triggers only happen once in a while. Now, it seems as though people are always on edge, and always stressed. Whether it’s being late for work, or anxiously checking the notifications on your phone, we’re never truly at peace. Chronic stress is what is bad for your health in the long term. 

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The physical effects of stress

Chronic stress has a multitude of negative physical effects on the body. For example, it can shrink parts of your brain related to learning and memory, cause shortness of breath, increase blood pressure, trigger acne and digestive problems to name a few. 

So, how do your negative emotions translate to physical problems? Stress releases a hormone called cortisol. Almost every part of your body has cortisol receptors, so this is why stress can physically affect almost every part of the body.

Cortisol is produced by the adrenal glands, small glands located on top of each kidney. It is designed to cut off blood supply to non-essential processes in the body and redirect it to your muscles, in the face of an immediate threat. Afterwards, cortisol levels go down and your body returns to normal. 

However, when cortisol is constantly produced, this becomes a problem. It triggers inflammation in various parts of the body, which explains things like acne and digestive issues. It also interferes with immune functions, paving the way for harmful pathogens to enter the body.

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Cortisol, stress and immune function

As mentioned before, cortisol is designed to suppress the immune system temporarily, so that the body’s resources can be directed to physical threats. However, when cortisol levels are always high, there is more permanent damage to the immune system.

Our immune system contains many different specialised cells that are designed to attack foreign pathogens. These are called lymphocytes (white blood cells), and there are two types: B-cells and T-cells. 

T-cells trigger immune reactions in several ways. For example, they can bind to an infected cell and kill it, so that the foreign pathogen can’t reproduce and spread to other cells. They also regulate the rest of the immune response through chemicals called cytokines

There have been many studies that looked at the link between psychological stress and immune function. In one study, dating as far back as 1984, studied how stress affects immune function in students getting ready for exams.

Blood samples were taken one month before and during the exams, where they looked at the T-cells in the blood samples. Interestingly, they found that T-cells were a lot less active during the exams when the students were highly stressed, which meant that the immune functions were weaker with increased stress.

Other studies have also found that life-threatening viruses like HIV propagated a lot more quickly in people who are more stressed. It is thought that stress levels can even affect the efficacy of vaccines, because vaccines depend on your immune system to ‘remember’ a harmful virus or bacteria.

So, if the immune system is already weak because of high stress, then the vaccinations might not be as effective. This information cannot be more important than now, when people are receiving Covid vaccines around the world. This is why it is very crucial to manage your stress levels in a pandemic, or in the winter when the flu is more common.

Managing stress 

So, what can you do? There are multiple ways to manage stress. But, here are a few:

  • Exercise:

Regular, aerobic exercises like jogging, running or cycling can help reduce stress levels. It directly increases ‘feel-good’ hormones called endorphins in the brain, which will improve your mood. However, remember not to overdo it with highly stressful workouts! Listen to your body, always and only do what you can handle.

  • Meditation:

Techniques like mindfulness meditation have been shown time and time again, to have positive physical effects on the brain and body. It can reverse some of the negative effects of chronic stress, like shrinkage in parts of the brain. 

The best part is that it doesn’t take that long to reap the benefits, and even 10 minutes a day can show massive improvements to your health.

  • Hobbies

Indulge in hobbies like art, playing an instrument, reading a book—even if it’s just for a few minutes in the day. Not only does it help manage stress, but there are added benefits to your brain functions (e.g. improving memory, hand-eye coordination, etc.

  • Turn off devices during work and before bed

Turn off devices for an hour or more before bedtime and during work. Constantly checking phones can raise stress levels and keep them elevated through the day. 

In conclusion

Stress is not just an emotion, it has lasting and dangerous physical effects on the body. It can compromise your immune function, by reducing T-cell activity—an important cell in the immune system that regulates immune response. Prolonged stress can pave the way for dangerous pathogens to enter the body and cause infection.

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