The link between stress and immune health

The link between stress and immune health - Nutrition Plus

As we approach cold and flu season, it’s essential to keep our immune systems sharp and prepared for whatever bug that’s going around. And in support of that, it’s important to lower stress levels.

Yes, you read that right. Mitigating stress can actually help strengthen your immune system! Let’s get into how stress impacts your immunity and what you can do to lower stress during the colder months.

Stress and the immune system

When we experience stress, it triggers a part of the nervous system called the autonomic nervous system. The body’s autonomic nervous system controls heart rate and blood pressure, regulates breathing, digestion, and how much cortisol (the stress hormone) is released. Stress stimulates the autonomic nervous system and prompts the adrenal glands to release adrenaline and cortisol, triggering our fight or flight response. Adrenaline elevates your heart rate and blood pressure, while cortisol increases glucose in the bloodstream to provide a burst of energy. Cortisol also represses bodily functions that aren’t absolutely vital to our survival in a fight or flight situation. This includes suppressing the digestive system, the reproductive system and –you guessed it– the immune system. 

We all undergo stressful situations at various points in our lives and that’s totally normal. While the stress response is meant to be helpful and keep us alert in times of danger, it can also take a toll on your mental and physical health when it’s constant. Continued activation of the stress response can leave us feeling overwhelmed and anxious, as well as mentally and physically exhausted. Over time, these effects can turn to impact your immune response as well.

How does stress impact immunity?

Our immune system is made up of many different types of cells. One of the main types of immune cells that help identify and kill harmful pathogens are known as white blood cells. Chronic stress affects a specific type of white blood cell, called lymphocytes, which are responsible for fighting off infections and protecting our bodies against threats.

When we experience chronic stress over long periods of time, the high levels of cortisol cause a decrease in the number of lymphocytes within the body. Too much cortisol suppresses the effectiveness of our immune response because we don’t have enough lymphocytes to fight the viruses, putting us at a greater risk of catching flus, viruses, and common colds. Over time, high stress levels eventually increase the amount of inflammation within our bodies. This is because chronic stress puts our immune system on over-drive, causing it to over-activate the inflammatory response. In the long run, this results in an overworked immune system that struggles to protect us properly.

The link between cold weather, immunity, & stress

As temperatures descend into the single digits, strengthening your immunity may be on your mind. And for good reason. While the drop in temperatures alone is not directly what causes you to get sick, it can be a contributing factor.

Research suggests that rhinoviruses (the most common viral infection and cause of the common cold) can replicate more efficiently at temperatures below 37°C, which is the average core body temperature in humans. Temperatures within the nasal cavity are around 33°C, making it ideal for rhinoviruses to populate. 

Additionally, researchers found that lower temperatures can decrease the effectiveness of the immune response. This could be because blood vessels in the upper respiratory tract tend to narrow to conserve heat when exposed to cold, dry air. This may prevent white blood cells from getting to the mucous membrane to fight off infectious particles, making it that much more important to have a strong immune system during winter months. Since experiencing high levels of stress only contributes to lower immunity, mitigating stress during this time is equally important.

What are some ways you can lower stress and boost immunity?

Reducing stress in your life can help you in more than one way, from improving your mood to supporting your immune response and overall health.

Stress-busting activities

Woman meditating beside her dog

Try to incorporate calming activities that you enjoy into your daily routine. This can look like:

  • Meditation
  • Yoga
  • Reading
  • Singing and dancing
  • Listening to a motivational podcast
  • Watching a funny movie or show
  • Spending quality time with loved ones
  • Getting restful sleep

Managing stress levels is different for everyone. What matters most is that you set aside some time for relaxation and distance yourself from anything that’s causing you to feel overwhelmed. A little self-care can go a long way!

Nutrients for stress relief and immune support

What you eat plays an essential role in helping you wind down and supporting your immune system. Here are a few multifunctional nutrients that can help reduce stress while strengthening the immune response:

Vitamin C

Citrus fruits such as oranges, grapefruits, and mandarins are all rich in vitamin C and antioxidants which are known to reduce cortisol levels. Vitamin C is also a natural immune booster that helps fight off harmful pathogens.


Fatty fish like salmon and mackerel are packed with omega-3 fatty acids, a nutrient that lowers stress by boosting serotonin (the happy hormone) levels. Omega-3s also reduce inflammation, support brain health, and promote a strong immune response.

Vitamin D

Sources of vitamin D (the sunshine vitamin) include milk, egg yolk, and fortified orange juice. This vitamin can help reduce feelings of anxiety and depression, lower inflammation, and boost the production of immune cells. Few foods are naturally rich in vitamin D, and we usually get enough from spending time outdoors under the sun. However, during winter, we get less exposure to the sun, making it more important to get our vitamin D from external sources such as diet and supplements.


Dark leafy green vegetables such as spinach, collard greens, and kale are great sources of magnesium, a mineral known to promote calmness, support lymphocytes, and as a result the immune response.

Stress doesn’t need to get in the way of building a strong immune system this cold & flu season. Make sure to practice self-care, load up on stress-relieving, immune-boosting nutrients, and stay warm!

Causes of Stress
How Does Stress Affect the Immune System?
What Happens When Your Immune System Gets Stressed Out?
How does Stress Affect Your Immune System?
What’s the link between cold weather and the common cold?
8 Stress-Reducing Foods to Nourish Your Body
New Research Suggests Magnesium and Vitamin D Can Help Reduce COVID-19 Infections
Vitamin D