How Does Stress Affect Your Immunity?
If you’ve ever come down with a cold after an important presentation at school or work, you may already suspect that stress can affect your immune system. You’d be right.
But, until now, you may not have thought about how stress negatively impacts your immunity.
In short, there’s a reciprocal relationship: stress can decrease immunity, and decreased immunity can also worsen psychological stress.
In this guide, we’ll take an in-depth look at the connection between the two. We’ll also provide tips on boosting your immunity and stressing less.
The Relationship Between Immunity and Stress
Although your body is made up of thousands of moving parts, you should think of it as a single organism. Each piece of the puzzle comes together to create a unified whole.
The interconnectedness between stress and the immune system is crystal clear.
A now-famous study from the 1980s demonstrated that stress can weaken the immune system.
- Psychologist Janice Kiecolt-Glaser, Ph.D., and immunologist Ronald Glaser, Ph.D. conducted an experiment that measured immunity and stress among medical students before and after their exams.
- After comparing blood samples from the students, the researchers found that the stressful three-day period of exams caused a decrease in natural immunity.
Further studies have only strengthened the outcome of that early research.
However, this summary only suggests that stress does affect your immune response. To investigate how stress affects the immune system, we have to dive deeper into the science behind stress and immunity.
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Why Do We Feel Stress?
It may seem unlikely that the pressure you feel from a looming deadline is a life-saver, but it’s true—in a sense. Stress triggers your “fight or flight” response in an attempt to protect you from danger.
When your body is under stress, it prepares itself instinctively for a negative outcome — which for much of human history meant serious physical harm. One of these innate preparations is to modify the immune response. We’ll touch on this more soon.
While this fight or flight reaction helped our ancestors navigate the dangers of their everyday life, it’s less useful in our modern world.
Today, most stress comes from life events that—while sometimes unpleasant—are not life-threatening. Upcoming exams, project presentations at work, the thought of a conversation you need to have with your spouse—these are all sources of stress in the 21st century. In these cases, stress is a way for our bodies to stay on high alert.
The Science Behind Stress
How can this familiar feeling have such a profound impact on the body?
When your body perceives a threat—real or imagined—your brain sends messages that tell your body to produce two hormones:[1]
- Cortisol – Often called the “stress hormone,” cortisol helps your body prepare for a stressful situation by increasing blood sugar and suppressing digestive, growth, and reproductive processes.
- Adrenaline – Also known as epinephrine, adrenaline kicks your body into high gear. The hormone raises your blood pressure, heart rate, and energy supplies.
Almost every cell in the body has receptors for one or both of these hormones, which means stress can impact all kinds of tissues and processes—including your immune response.
Under normal circumstances, your central nervous system should return to normal after a stressor disappears. Keep in mind that short bursts of stress aren’t harmful. In fact, they protect us from hazards.
However, long-term, chronic stress may negatively affect your immune system.
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