Stress might age the immune system, new study finds
NEW YORK — By now, most people know that stress can take a serious toll on mental and physical health. And when that stress is prolonged, studies suggest, it can increase the risk of certain health conditions like asthma, ulcers, heart attack and stroke.
Now, new research suggests that certain types of stress can even age your immune system.
Using an existing body of data, researchers looked at survey responses from a nationally representative sample of more than 5,700 adults in the United States ages 50 and older, and cross-referenced them with immune cell counts from participants’ blood.
The survey asked respondents about their experiences with social stressors like job strain, chronic stress, stressful life events, everyday or lifetime discrimination (including sexism or ageism) and traumatic life events.
The team found that higher levels of reported stress were associated with older immune system profiles. The findings were published in The Proceedings of the National Academy of Sciences.
WHAT THE FINDINGS SUGGEST
As your immune system ages, your body has a less coordinated response to new threats because it produces different types of immune cells in different proportions than it does when you are younger, said Dr Eric Klopack, the lead author of the study and a postdoctoral researcher of gerontology at the University of Southern California.
At the same time, older, more worn-out immune cells tend to dominate over newer, more agile ones, resulting in a less robust immune response.
Until now, no one has fully investigated the relationship between social stress and immunological function, at least not with this granularity, said Dr Matthew Yousefzadeh, who researches aging at the University of Minnesota and was not involved with the new research.
And while the new study is limited in that it only looked at a few kinds of immune cells — specifically the T cells CD4 and CD8 — Dr Yousefzadeh said that they are a pretty good indicator of immunity robustness.
“It’s sort of a peek underneath the hood of the car and how well you’ll do with the infections,” he said.
The new research touches on a timely concern amid the ongoing Covid-19 pandemic. “I think a lot of people right now are looking at ways to rejuvenate or stimulate or boost the immune systems, particularly with aging,” Dr Yousefzadeh said.
And so any information on how immune aging works, or how it might differ for certain people, is valuable for public health.
WHAT YOU CAN DO
While the researchers found that certain forms of social stress were linked with changes in participants’ immune cells, Dr Klopack cautioned that experts don’t fully understand how one influences the other.
When they statistically controlled for behaviors like smoking or drinking, some of those associations with immune aging “went away or were reduced,” he said, suggesting that those behaviours may have played some role in the aging of their immune systems.
One way to prevent immune cell aging, then, Dr Klopack said, may be to be mindful of unhealthy habits.
Studies like this one make visible what people who endure discrimination and trauma already intuitively know, said Ms Renee Eddy, a psychotherapist based in New York City: Stress takes a tangible toll on physical health.
Mitigating those effects requires taking stock of your emotions, Ms Eddy said. Everyone is affected by stress differently, she said, so the ways they process it can vary too.
Focusing on what brings you joy, and where you can find social support, can help. That may mean pursuing hobbies, spending time with loved ones, or unplugging from work or social media when you can.
Mindfulness practices, exercise and healthy eating habits can also help you feel good physically, which in turn can make you feel good mentally, she added.
If you experience social stressors on a daily basis — whether at work, in your social life or at home — think about what you can control to keep them in check, Ms Eddy said.
If a friend’s political views are consistently causing you anguish, can you limit your contact with them or change your social circle?
If a work colleague is putting you down because of your age, would it help to confront them about it? Looking at the full context of where and how stressful situations manifest in your life is the first step in deciding how you can move forward.
Of course there will be situations that you cannot control, Ms Eddy added, but the more you can do to better understand their effect on you, the more you can do to help alleviate them.
There is a lot more to uncover, Dr Klopack said. The new study looked at older, mostly white adults, at one point in time, relying on self-reported stress levels.
Scientists don’t know how stress affects the immune systems of younger people, or how changes to immune systems may persist.
One thing to remember, however, is that the biggest thing “that contributes to immune aging is just aging,” said Dr Idan Shalev, a bio-behavioural health scientist at Pennsylvania State University who studies the effects of stress across life spans.
So the strategies for warding off immune aging are usually the same ones that will ward off the effects of aging in general: Following a healthy diet, getting regular exercise, limiting or avoiding smoking and drinking, and getting good sleep.
“Having social supports is also very important, like family, friends,” Dr Shalev said, since loneliness can also affect the immune system.
We should all be implementing those good habits right away, he added, and not just waiting until you’re close to retirement.
Another way to interpret this new study, Dr Yousefzadeh said, is that social stressors like trauma and discrimination can affect life expectancy.
But while there is much research interest in rejuvenating our immune system, science has yet to find a way to reverse aging, he added.
So it’s important to do everything you can to keep your immune system robust, he said, because once things decline, you cannot really go back to how things were.
This article originally appeared in The New York Times.