Stress and the Immune System

Dr. Amanda Capasso

Stress and the Immune System

Stress and the Immune System

The official start to fall is here and the change of season means that cold and flu season is just around the corner. Now is a great time to boost your immune system and one of the best ways to do that is to better manage stress. Most people have heard that stress impacts their immune system but today I want to take a deeper look into what that ubiquitous statement means and what you can do about it.

You’d be hard pressed to find someone these days who has not experienced stress at some point in their life. Whether it’s a big exam, a breakup, a job deadline, a family member being ill etc., there are no shortages of stressful situations in today’s world. When our brain perceives stress it signals to our adrenal glands to produce adrenaline and cortisol. The release of adrenaline activates the “fight or flight” response and the release of cortisol mobilizes energy reserves to be able to fuel the body through the stressful event. In the short term, the stress response is a very adaptive mechanism that has contributed to human evolution and survival. It’s when the stress response becomes chronically activated that we start to see detrimental effects on health and the immune system. 

Chronic or long-term stress is defined as perceived stress for several hours a day that lasts for weeks. Chronic stressors and the body’s inability to shut the stress response down can cause sustained cortisol release even when the adrenaline response subsides[1]. Elevated cortisol leads to impaired immune function through a redistribution and decrease in the number of immune cells[1]. Long-term stress simultaneously causes an increase in immunopathology and immunosuppression[1]. An increase in immunopathology causes increased inflammation and increased flare ups of autoimmune disease. I see this often in patients with crohn’s or colitis (both autoimmune diseases) where symptoms worsen during times of prolonged stress. I also see the flip side where patients present with symptoms of increased immunosuppression where the chronic stress has weakened their body’s ability to fight off infection or heal injuries.

Breaking that chronic stress response cycle is critical in improving immune function. Some people don’t realize how much stress they are carrying and learning to unload or delegate or say “no” can have a big impact. For other people, the stressors can not be avoided and that’s when education around stress management becomes pertinent. Below are some of my favourite ways to help the body deal with chronic stress:

1. Mindfullness

You don’t need to become the Dalai Lama to experience the benefits of mindfulness. Mindfulness teaches you to focus only on what’s happening in the present and to not dwell on situations from the past or make predictions about the future. Mindfulness can start as simply as making a commitment to be present while brushing your teeth. Its something most of us do everyday while on autopilot. Instead, try to be present to everything that’s going on. The colour and taste of the toothpaste, how the bristles feel against your teeth and gums etc. Building off that exercise, mindfulness can become a part of your daily life and greatly reduce stress.

2. Social activities and connection

As human beings we are hard wired for connection. Making time for people (or pets!) you love in your life can help relieve chronic stress. When you do make time to be with those you love, focus on being present and try not to multitask. It can be as simple as inviting a friend to come for a walk you were already planning on taking, carving out a couple hours on a weekend to spend time with those you love or finding a new way to meet people.

3. Dietary changes

Historically, starvation or lack of food was one of the biggest stressors on our body.Today, I have patients whose diets are calorically sufficient but nutritiously sparse which contributes to a chronic stress response. Ultra processed grains, sugars, oils, and meats are high in calories but low in nutrients, signalling to the brain food may be scarce. Sudden drops in blood sugar from diets high in refined carbohydrates and sugar also lead to big surges in cortisol. A diet rich in whole foods that is balanced with healthy fats and proteins can reduce physiological stress on the body. I caution patients from jumping on the intermittent fasting train as its not for everyone. In an already stressed out body, intermittent fasting adds additional stress and can often exacerbate symptoms of stress.

4. Exercise

During acute stress, high intensity exercise can be a great way to burn off cortisol but during chronic or long term stress, high intensity exercise can become detrimental. Intense physical exercise puts additional stress on an already stressed out body and can make symptoms of chronic stress, including immune function, worse. That doesn’t mean you shouldn’t move at all though. Mild-moderate exercise can be a great way to deal with chronic stress. Activities like walking, gentle biking, yoga, and pilates can all improve your resistance to stress.

5. Supplements

Supporting the adrenal glands with essential nutrients like vitamin C, B vitamins, magnesium and adaptogenic herbs can be helpful for long term stress recovery. Urinary or salivary cortisol testing is available through your naturopathic doctor and can give you a better picture of cortisol function throughout the day. If testing is done, more targeted supplements are usually recommended.

If you or someone you know is struggling with an impaired immune system or chronic stress, a naturopathic doctor can help. We will spend an hour an a half going through health history, medications, family history and lifestyle to tailor a plan to give you the tools to better manage stress and improve overall immune function.


1) Dhabhar, F. Enhancing versus suppressive effects of stress on immune function: Implications for   immunoprotection and immunopathology. Neuroimmunomodulation. 2009 Jun; 16(5): 300-317.