Can Stress Affect Your Immune System? Experts Break It Down

Stress (and the overwhelm and anxiety that often come with it) is bad enough on its own, but can it actually make you sick? We talked to the experts to get the lowdown on the relationship between chronic stress, illness, and lingering physical symptoms.

Chronic stress (coupled with inadequate sleep) is the most common reason people get sick, Heather Moday, M.D., an allergist and immunologist, previously told mbg. "When we are run down and cortisol soars, our virus surveillance cells dip and we get sick more easily," she explains. "Cortisol itself interferes with the ability of specific white blood cells called T-cells to proliferate and get signals from the body. In addition, cortisol also lowers an important antibody called secretory IgA, which lines the respiratory tract and gut and is our first line of defense against invading pathogens."

When you're stressed, you're also more likely to lean toward unhealthy coping mechanisms, like overindulging in "comfort foods" that are high in sugar or refined carbs (you can learn more about the impact of those foods here), smoking, and drinking in excess—all behaviors that increase the chances of getting sick.

While that's a big problem, it's not the only problem associated with stress. In addition to increasing the likelihood that you'll catch the next bug going around, chronic stress can also cause some gnarly physical symptoms:

If you've ever been under a lot of stress, you probably don't need anyone to tell you that headaches can develop as a result, but just in case: "One of the most common physical reactions to stress is the tensing of muscles, which can ultimately trigger tension headaches, migraines, and other musculoskeletal conditions," says Isaac Eliaz, M.D., M.S., LAc, founder and medical director of Amitabha Medical Clinic. 

In addition to headaches, tense muscles can lead to widespread muscle pain. This pain can affect all parts of the body, but the neck and shoulders are common places where people hold tension2. Facial pain3, specifically in the ears, teeth, and head, can also develop as a result of stress (and likely jaw clenching that comes with it). Plus, there seems to be a correlation between stress and pain sensitivity, meaning that when you're feeling really stressed out, things just seem to hurt more.

When it comes to sleep, stress is a double-edged sword. Chronic stress can lead to insomnia and sleeping troubles, and lack of proper sleep can increase the body's stress response. Eudene Harry, M.D., medical director for Oasis Wellness and Rejuvenation Center, explains that when you're chronically stressed, you're in a constant state of high adrenaline, which makes it difficult to wind down and get the sleep you need.

If you're not sleeping well because of stress, you'll likely feel tired pretty often. But chronic stress can cause fatigue that's not alleviated by rest or sleep. One study found that a high level of stress can lead to "unexplained" fatigue4. This type of stress fatigue can also lead to impaired performance and function throughout the day. Translation: It's harder to get basic tasks done and/or focus on your work. That's because chronically high levels of cortisol can deplete your adrenal glands, which makes you feel like you're running on empty, according to Lissa Rankin, M.D.

Stress may not directly lead to blemishes, just like it doesn't directly cause you to get sick, but it can increase the severity or trigger an onset of skin issues. Researchers from an older study published in JAMA Dermatology looked at a small group of 22 participants, and even when controlling for other breakout-causing factors, like lack of sleep and poor diet quality, they found that increases in stress were positively correlated with more severe skin concerns5.

"Stress is also hard on your digestive system, as it affects which nutrients your intestines absorb, influences how quickly food moves through your body, and can provoke you to eat more or less than you normally do," says Eliaz. "In turn, this can cause nausea, pain, vomiting, heartburn, constipation, acid reflux, and/or diarrhea."

When you're stressed, the brain releases a neurotransmitter called acetylcholine6 (ACh). ACh activates the nervous system, which sends signals to the sweat glands that increase sweating all over the body but especially on your palms, soles, face, and underarms.

When you're under stress, the release of cortisol and adrenaline triggers the "fight or flight" response, which increases the contractions in your heart muscles and, as a result, your blood pressure and heart rate. If stress is chronic, your blood pressure and heart rate can stay elevated for an extended period of time, which can increase your risk of developing more serious problems.

Here are some things you can do to support both your mental well-being and physical health:*

Of course, it's always a good idea to chat with your doctor about any lingering physical symptoms to rule out any other underlying causes.