why is stress so bad for our immune systems?
study finds that stress not only impacts the heart and blood pressure, but it also ages our immune systems and makes it more difficult to fight infections, like covid-19.
3 minute read
study finds that high levels of stress is linked to having a weaker immune system. getty
stress is bad for us in a number of ways: it can increase our heart rate and blood pressure, cause stomach distress and even trigger asthma attacks. but according to a new study, we don’t just have to worry about the direct impacts of stress on our bodies: it can also affect the function of our immune systems.
there’s a huge amount of evidence that stress related to discrimination and to traumatic events can cause serious damage to health. for that reason, researchers in this study, published in proceedings of the national academy of sciences, decided to focus on something different: social stress related to relationships and the way we get along with other people. they found that social stress is associated with increased aging of the immune system.
“immune aging may help explain why older people tend to benefit less from vaccines and why they have more serious complications associated with infections like covid-19,” prof. erik klopack, one of the study’s lead authors, told healthline.
the study’s authors used data from the health and retirement study, a large-scale study of adults over 50 across the u.s. they surveyed participants about their stress levels, and took blood samples. they were particularly interested in observing the white blood cells.
advertisement
white blood cells are crucial in immune response to viruses and bacteria because they contain t cells, which focus on defending the body from foreign particles. t cells are born “naive,” klopack wrote in the washington post, meaning they’re available in our bodies to fight new “invaders.” as we age, our t cells may become “memory t cells,” which essentially “remember” how to fight illnesses we’ve had before. (that’s why for many people who are not immunocompromised, getting covid a second time will not be as bad as their first infection: “immediately your memory t cells from your vaccination are going to say, ‘whoa, i’ve seen that guy before; time to go out and start killing these cells that are infected with it,'” university of saskatchewan virologist angela rasmussen explained to cbc news. but many people with compromised immune systems have lower t cell counts or problems with t cell production, which means they don’t have the same protection from a first infection.
t cells also have the potential to turn into “terminally differentiated” or “late differentiated” t cells, which have essentially exhausted their capacity for defence, and can become harmful for our other cells.
advertisement
while this change is a normal part of our aging process, the study found that this process is accelerated in people with high levels of social stress: the people who reported high levels of stress had fewer naive t cells and more differentiated cells.
“there is still more research needed, but there is evidence that people with more aged immune systems are less able to fight acute infections, like the flu or covid-19, are at greater risk of cardiovascular disease, and are at greater risk of mortality,” klopack told healthline.
that doesn’t mean people with high stress levels are powerless.
“after we controlled for poor diet and low exercise… the connection between stress and accelerated immune aging wasn’t as strong,” klopack wrote in the post. “this suggests that improving these health behaviours might help offset the hazards associated with stress.”
there are obviously a huge number of stressful things in our world: climate change, cost of living, war overseas. canadians are particularly worried about inflation and housing affordability, according to a recent angus reid poll. and of course, marginalized people are forced to deal with discrimination, racism and homophobia, which all have major impacts on physical and mental health.
advertisement
these are all real problems, and ones that aren’t easily solved. but it’s also true that many of the factors that can reduce stress are things we know about, but often have trouble doing: healthline points out that in addition to regular exercise and healthy eating, getting enough sleep can have major benefits, as can having a support network.
there are some limitations to the study: all the participants are american, for one thing. their stress levels may not represent the specific forms of stress that face younger people. and researchers also posit that people with very high stress levels may not be represented in the study, as they may have died before reaching old age.
maija kappler is a reporter and editor at healthing. you can reach her at mkappler@postmedia.com
thank you for your support. if you liked this story, please send it to a friend. every share counts.
share story
