Does Stress Weaken Your Immune System?

By Holly King


Does Stress Weaken Your Immune System?

Article at a Glance:

  • Even short periods of stress can weaken essential aspects of your immune function.
  • Stress decreases the output of critical immune cells and increases cortisol levels, both of which weaken the immune system.
  • Common stress coping behaviors like smoking, drinking, and eating poorly can also contribute to a sluggish immune system.
  • Frequent stomach trouble, fatigue, and constantly catching bugs are signs that your immune system is already struggling.
  • If you want to support your immune system, make time for stress-relieving activities and practice healthy lifestyle habits like eating well, staying hydrated, exercising, and relying on immune-supporting vitamins, minerals, and herbs.

The November - January stretch is beloved by many. Full of festive fun, busy schedules, and time spent with loved ones, there’s a reason we call it “the most wonderful time of the year”.

So why do we come away from the holiday season feeling even more stressed? Keeping up with hectic schedules and complicated relationship dynamics often leaves us feeling burned out and more spent than we were before the break

Unfortunately, when we’re fighting the levels of stress that are so common this time of year (combined with the seasonal bugs that are so common this time of year), our immune system takes a heavy hit and can’t keep up for long. That’s why so many of us get sick during or after the holidays.

Here we’ll discuss why stress takes such a toll on your immune system and a few ways to keep your immune system strong during the holidays and beyond.

How Stress Impacts Your Immune System

In the early 1980s, two researchers at Ohio State University College of Medicine discovered an interesting connection between high stress levels and high infection rates in rats. Since this discovery, there have been countless studies conducted on stress and immune health in humans.

These studies have uncovered surprising findings— like the fact that even short bouts of stress can weaken your immune system in measurable ways. In fact, a 2004 research meta-analysis determined that any duration of stress, whether it’s a few days or a few months, can lower all aspects of your immunity.

One study in graduate students found that their immune function was weakened over the course of a three-day exam period. These graduate students had lower levels of natural killer cells (immune cells that help fight off the bacteria, viruses, and other harmful invaders that enter your body). The students had lower levels of T-cells (another type of critical immune cell) and gamma interferon (an immune protein released by T-cells that helps modulate immune response) as well.

When we stress, we also produce cortisol— the primary stress hormone. Cortisol increases glucose levels in the blood and brain, which heightens inflammation and limits the body’s ability to fight infection. High cortisol levels can trigger anxiety, depression, and the progression of chronic diseases like arthritis, IBS, and fibromyalgia too.

Protecting our immune system from stress is only made harder by the desire to cope with stressors via unhealthy methods. Coping strategies like smoking, drinking, over-exercising, eating junk food, staying up all night to get more done can weaken an already struggling immune system even further.

3 Signs Stress Has Already Weakened Your Immune System

A weak immune system can manifest itself in many ways, ranging in severity from mild warning signs to fully diagnosed immunodeficiency. Here are some of the most common signs that stress has started to take a toll on your immune system:

Stomach Troubles

If you are always having stomach troubles— gas, constipation, or diarrhea —it’s possible that your immune system needs strengthening. More than half of our immune system is located in the digestive tract, making it hard to have a healthy gut without a healthy immune system and vice versa.


Being tired all the time is also a tell-tale sign of a weak link in the immune system. When our immune system isn’t functioning properly, it reserves the little energy it has to fight off infections and germs, leaving us feeling fatigued and with a lack of focus.

Constant Sickness

Have you already had your fair share of bugs this season? Frequent sickness, or not being able to recover from a cold within the standard 7-10 days, could be a sign your immune system is struggling.

How to Strengthen Your Immune System

During this busy time of the year, don’t just view stress as a means to an end or a byproduct of your to-do list; recognize the power it can have over your body and the power you have to prevent it. Consider making time for stress-reducing activities like:

  • Meditation or yoga
  • Breathing exercises
  • Reading
  • Walking
  • Laughing
  • Resting
  • Hugging
  • Anything else that helps you naturally reduce stress

There’s no doubt that relieving stress will help your immune system function at its best. But if you really want to keep your immune system strong and healthy, it's important to go beyond just stress relief. Take care of your immune system with other healthy habits too, like:

  • Eating a balanced diet
  • Hydrating properly
  • Getting regular exercise
  • Washing your hands
  • Prioritizing a mix of key immune-supporting vitamins, minerals, and herbs (like the ones you’ll find in Re-Lyte Immunity)

Check out our 7 Pillar Plan for Ultimate Immune Health for even more ideas!


Psychological Stress and the Human Immune System: A Meta-Analytic Study of 30 Years of Inquiry - US National Library of Medicine

Stress Weakens the Immune System - American Psychological Association

Primary Immunodeficiency - Mayo Clinic

6 Signs You Have a Weakened Immune System - Penn Medicine

The role of gut microbiota in immune homeostasis and autoimmunity - US National Library of Medicine

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