Stress, You Make Me Sick (Literally)

New research shows stress isn't just bad for your mood, but your immunity

Posted Apr 11, 2018

Kelly Durbin, used with permission
Source: Kelly Durbin, used with permission

This guest post was contributed by Kelly Durbin, a graduate student in the USC Psychology Department's Clinical Science program.

It’s Friday night and your glazed eyes stare vaguely at the wine labels. Between the long commutes, frustrating colleagues, and looming deadlines, you feel exhausted from all the stress and just want to take the edge off. You briskly walk towards the only available cashier with your Cabernet Sauvignon, when suddenly you are intercepted by a woman who manages to get in line a millisecond before you do. As she apologetically looks at you, you sharply inhale and purse your lips into a disingenuous smile. “Of course,” you think to yourself. As she slowly unpacks her overloaded cart, you begin to feel your heart pounding in your ears when suddenly the cashier stops scanning the items. There seems to be a problem. You watch in horror as the cashier reaches for the phone. “Manager to 6!” You stare down at your one item in disbelief. “Oh, for crying out loud!” you scream internally. You start conspicuously tapping your foot and letting out deep audible sighs in an effort to convey your frustration to everyone around you. As you finally walk out of the store, you are still fuming. You think, “I am so sick and tired of there always being a problem.” But what you may not realize is that living your life with this level of stress and frustration can make you sick and tired, literally.

Pxhere, Creative Commons license
Source: Pxhere, Creative Commons license

Studies have shown that people with high stress levels – like the stressed out person I just described – are more likely to get sick during cold and flu season. One reason is that chronic stress can trigger a biological cascade that suppresses the immune system, lowering the body’s ability to protect against infection. So as you are standing in the checkout line grumbling about how annoying your week has been, you are also increasing your chances of catching a cold from the person who is coughing and sneezing behind you.

Surprisingly, stress can even influence how the body responds to vaccinations. For example, chronic stress can make the flu shot less effective, thereby increasing your chance of getting the flu. And it can also make other vaccinations less effective. Ronald Glaser and Janice K. Kiecolt-Glaser, researchers at The Ohio State University College of Medicine, found that stress can affect the body’s response to the flu shot as well as vaccinations for hepatitis B, meningococcal C infection, pneumococcal disease, and rubella. The authors reported that, “individuals who were more distressed and more anxious had immune responses to vaccines that were delayed, substantially weaker and/or shorter-lived.”

Even fluctuations in your mood after getting a flu shot can have an impact. In a 2018 study, researchers from the University of California, Irvine and Chapman University asked people who just received the flu shot to record their mood four times a day for nearly two weeks. To do this, people judged how relevant a list of adjectives (e.g., nervous, unhappy, enthusiastic, relaxed) was to their current mood state. They found that people who showed more variability in their mood had a worse response to the flu vaccine.

Pxhere, Creative Commons license
Source: Pxhere, Creative Commons license

Although stress can increase your risk of getting a cold or the flu, it does not guarantee it. It is just one of the many negative consequences that can occur from too much stress. So the next time that you are angrily stuck in traffic or impatiently waiting in a checkout line at the grocery store, ask yourself, is this really worth getting sick over?


Glaser, R., & Kiecolt-Glaser, J. K. (2005). Stress-induced immune dysfunction: Implications for health. Nature Reviews Immunology, 5(3), 243-251.

Jenkins, B. N., Hunter, J. F., Cross, M. P., Acevedo, A. M., & Pressman, S. D. (2018). When is affect variability bad for health? The association between affect variability and immune response to the influenza vaccination. Journal of Psychosomatic Research, 104, 41-47.

Reed, R. G., & Raison, C. L. (2016). Stress and the immune system. In C. Esser (Ed.), Environmental influences on the immune system (pp. 97-126). Vienna: Springer.

Sapolsky, R. M. (2004). Why zebras don’t get ulcers: The acclaimed guide to stress, stress-related diseases, and coping (3rd ed.). New York, NY: Holt Paperbacks.

Segerstrom, S. C., & Miller, G. E. (2004). Psychological stress and the human immune system: A meta-analytic study of 30 years of inquiry. Psychological Bulletin, 130(4), 601-630.