One of the ways this can occur is through a weakening of your immune system, which can leave you more vulnerable to everyday infections, but also to more serious immune conditions such as an autoimmune disease.
In this article we'll look at the relationship between chronic stress and the immune system, and show you some ways by which you can reduce your stress levels.
The basics of immunity
The immune system has many functions, but its main goal is to protect the body. It prevents infections caused by germs (or pathogens) and heals damaged tissue caused by injury or illness.1, 2
The immune system has two main branches. The first is innate immunity, which is a rapid general response to any general threats discovered within the body. This response is not specific to the threat, much like a broad-spectrum antibiotic.3
The second is acquired immunity, which activates when it comes across microbes, and focuses on learning about the threat so that it can be protected against in future. This is highly specific to the threat presented, meaning it will fight different types and strains of viruses and bacteria accordingly.3
Many factors can affect how the immune system works, including environmental factors such as heavy metals, tobacco smoke and nutritional deficiencies and internal factors such as genetic tendencies, stress levels and even the types of bacteria that naturally live in your bowel.4
How stress affects the immune system
Stress can affect the immune system both directly and indirectly. It can suppress immune cells, contribute to inflammation and induce a constant fight-or-flight response as described below.
Suppressing immune cells
Stress can suppress the production and function of white blood cells (WBCs). These act as the soldiers of the immune system and play a major role in both the innate and adaptive immune responses.3 Acute stress can reduce the level of two major types of WBC, monocytes and natural killer cells, while chronic stress can impair the function of T-cells (another type of WBC).5, 6
Inflammation is one way the immune system promotes healing and prevents further damage. A normal inflammatory response dilates blood capillaries to bring more WBCs and nutrients into an injured area, as well as immune factors such as antibodies.7
However, chronic inflammation can lead to more harm than good. Research has shown that chronic stress can inhibit the body's regulation of inflammation, which can ultimately lead to chronic inflammation and long-term effects on immunity.9
When we experience stress, the body switches into a survival response known as the fight-or-flight reaction. This primes bodily systems to deal with a perceived threat. Stress hormones flood throughout the body to put it on high alert, causing blood to move away from the gut to the muscles and the heart rate and blood pressure to increase ready to fight or flee. This can lead to symptoms such as nausea, palpitations and anxiety.10
While this is useful for certain situations, chronic stress can cause a constant state of alertness within the body which could ultimately suppress the immune system.11 It can also make WBCs more sensitive to the stress hormones produced during the fight-or-flight response.12
Chronic stress doesn't just weaken the immune system. It can also increase your risk of developing an autoimmune disease. One study analysed over 100,000 people with stress-related conditions, and found they were more likely to be diagnosed with an autoimmune condition. They were also more likely to develop more than one autoimmune condition, which suggests that stress can cause significant issues with regulating the immune system.13
How relieving stress supports immunity
If acute and chronic stress can suppress the immune system, then relieving stress is key for healthy immunity. By lowering your stress levels you can help to relieve inflammation, WBC suppression and prevent the occurrence of chronic fight-or-flight mode.
Different stress relief techniques have different benefits for the immune system. One study showed that relieving stress with laughter could boost natural killer cell levels.14 Lifestyle changes, such as following a healthy, nutrient rich diet to avoid vitamin and mineral deficiencies, and exercising regularly to reset the fight-or-flight response towards a rest-and-digest mode, will also help.
Taking steps to identify the stress-inducing parts of your day and learning how to reduce them will make a difference, too. It's important to make sure you get enough high-quality sleep, as this could affect not only your stress levels, but also your immune health more broadly.
If you're interested in learning more about how to keep your immune system healthy, head over to our Immunity Advice Centre.