Stress can age the immune system, study suggests

Most people already know that stress can have serious consequences for mental and physical health. And when stress is prolonged, studies suggest, it can raise the risk of certain health problems, such as asthma, ulcers, heart attack and stroke.

Now research suggests that certain types of stress can even age the immune system.

Using a preexisting dataset, researchers analyzed responses to a survey with a nationally representative sample of more than 5,700 adults in the United States aged 50 years and older and compared them with immune cell counts in the participants’ blood.

Participants were asked to answer questions about their experiences with social stressors such as job strain, chronic stress, stressful life events, everyday or lifelong discrimination (including sexism and age discrimination), as well as 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 do the conclusions suggest?

When your immune system ages, your body has a less coordinated response to new threats, as it produces different types of immune cells in different proportions than it did when you were younger, according to the study’s lead author, Eric Klopack, a postdoctoral researcher. in gerontology at the University of Southern California. At the same time, older, more tired immune cells tend to predominate over new, more agile ones, resulting in a less robust immune response.

No one has yet fully investigated the relationship between social stress and immune function, at least not in this level of detail, said Matthew Yousefzadeh, who researches aging at the University of Minnesota and was not involved in the new research.

And while the new study is limited in that it only looked at a few types of immune cells, specifically CD4 and CD8 T cells, Yousefzadeh said they are a good indicator of immune robustness. “It’s like looking under the hood of your car and seeing how well you’re going to resist infections,” he said.

The work addresses a timely concern amid the ongoing Covid pandemic. “I think right now there are a lot of people who are looking for ways to rejuvenate, stimulate or bolster the immune system, especially as they age,” Yousefzadeh said.

So any information about how immune aging works and how it might differ for certain people is valuable for public health.

What can you do

Scientists have found that certain forms of social stress are linked to changes in people’s immune cells, but Klopack cautioned that they still don’t have a complete picture of how one thing influences another.

When they did a statistical control to account for behaviors such as smoking or alcohol consumption, some of the associations with immune aging “disappeared or were reduced”, said the expert, suggesting that these behaviors may have played some role in the aging of the immune system of the patients. participants.

So, Klopack said, one way to prevent immune cells from aging may be to be careful not to have unhealthy habits.

For psychotherapist Renee Eddy, from New York, studies like this one make visible something that is already intuitively known by people who suffer discrimination and trauma: namely, that stress has concrete negative consequences for physical health.

To mitigate these effects, she said, you need to take stock of your emotions. Each person is affected differently by stress, so the ways in which everyone processes stress can vary as well.

Focusing on what gives you joy and activities where you find social support can help. This can mean enjoying hobbies, spending time with loved ones, or, when possible, disconnecting from work and social media.

Mindfulness practices, exercise and healthy eating also help you feel good physically, she said, and that, in turn, can make you feel good mentally.

If you experience social stressors on a daily basis – at work, at home or in your social life – think about what you can control. If a friend’s political views cause you constant distress, how about limiting your contact with that person or changing your social circle? If a coworker is treating you lightly because of your age, would it be helpful to confront him directly? Looking at the full context of where and how stressful situations manifest in your life is the first step towards overcoming them.

Of course, there will be situations that are out of your control, Eddy said. But the more you understand their effect on you, the more you will be able to alleviate those effects.

For Klopack, much more remains to be discovered. The new study looked at older, mostly white adults at a point in time, and was based on self-reported stress levels. Scientists don’t know how stress affects the immune system of younger people, nor how changes to the immune system can persist.

One thing worth remembering, however, is that the single most important thing “that contributes to immune aging is just aging,” said Idan Shalev, a biobehavioral health scientist at Pennsylvania State University who studies the effects of stress throughout life. life.

Thus, the strategies to prevent immune aging are generally the same ones that will delay the effects in general: healthy eating, regular physical exercise, limiting or avoiding cigarettes and alcohol, sleeping well.

“Having social supports, like family and friends, is also very important,” Shalev said, as loneliness can also affect the immune system.

For them, we should all start implementing these good habits now, and not wait until we get close to retirement age.

For Yousefzadeh, another way to interpret this new study is to understand that social stressors such as trauma and discrimination can affect life expectancy. But while there is a lot of interest in research on immune system rejuvenation, science has yet to find a way to reverse aging, he explained.

So it’s important to do everything you can to keep your immune system robust, he said, because once things go downhill, you can’t really go back to the way they were before.

Translation by Clara Allain