4 Ways Stress Is Linked to Your Immune System

The immune system is our body's main line of defense when it comes to intruders, like infections that can make us sick. Think of it like a tiny-but-mighty army that's always on standby to defend its homeland (aka your body).

While some of what keeps our immune system healthy can be chalked up to genetics, there are some practices, including eating well and exercising, that help keep everything running smoothly. By that same token, there are factors that can weaken our immune system, and stress is a big one.

Below are some of the ways stress can interfere with the tactics of our bodies' battalion.

Cortisol, the critical hormone our bodies produce to self-regulate, gets made in abundance when we experience chronic stress. This can pose a whole host of health risks, but the immune response in particular can be compromised.

Per a June 2014 review published in ​Age​, glucocorticoids, which are by-products of stress, can slow the production of B cells and T cells, the main cellular components of the immune system.

"Never underestimate the power of a calm mind to ameliorate the symptoms that we experience"

"Each and every day, your body makes a little bit of cortisol and it helps regulate everything," J. Allen Meadows, MD, allergist and president of the American College of Allergy, Asthma and Immunology, tells LIVESTRONG.com. "It's part of the flight-or-fight response, and for short periods of time there's no problem with that. Making an extra burst of cortisol when you're trying to get away from a tiger — that's a good thing."

But when cortisol gets pumped into the blood at increased levels for prolonged periods, the body adjusts and gets used to extra amounts. This, in turn, puts the body at greater risk for inflammation and, thus, a weaker immune system, per the Cleveland Clinic.

"There's clear evidence that stress, anxiety and depression make illnesses more difficult to treat," says Dr. Meadows. "I've had many patients that, unless their [stress] is adequately treated, it's almost impossible to treat their illness."

Too much stress "down-regulates your immune system so you're not fighting infection as well," he says, adding that in these instances, the immune system is not as active as it could be.

On the other hand, low stress levels can make a positive difference in treatment. "Never underestimate the power of a calm mind to ameliorate the symptoms that we experience," Dr. Meadows says.

Intense levels of stress may potentially increase your odds for developing an autoimmune disease, according to a June 2018 study published in the ​Journal of American Medicine​. Researchers compared more than 106,000 people who were diagnosed with stress disorders with more than 1 million people without them and found that stress was tied to a 36 percent greater risk of developing dozens of autoimmune diseases, including Crohn's disease, psoriasis and rheumatoid arthritis.

"Patients who have severe emotional reactions after trauma or other life stressors should seek medical treatment due to the risk of chronicity of these symptoms and thereby further health decline, such as the increased risk of autoimmune disease," the study's lead researcher, Dr. Huan Song, said in a statement.

Whether stress can actually cause cancer is still very much up for debate. But evidence does suggest that stress is linked to an increased risk for the disease.

An October 2017 study published in ​Scientific Reports​ examined the link between stress levels and cancer in more than 100,000 people. While researchers did not find a correlation between short-term stress and cancer, they did find that those who experienced consistent, high-level stress for prolonged periods of time had an 11 percent greater risk for developing cancer. This correlation was found to be more likely in men.

Similarly, researchers found a significant link between work stress and the risk of cancer in a meta-analysis of observational studies published in a December 2018 issue of the ​International Journal of Cancer​. More specifically, they found an association between work stress and the risk of colorectal, lung and esophageal cancer, and no association with the risk of prostate, ovarian or breast cancer.