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Experts say it’s important to learn how to handle stress, even at a younger age. Maskot/Getty Images
  • Experts say there are two types of stress: Physical and psychological
  • Researchers say stress of any kind can accelerate the aging process of our immune systems as we get older.
  • Experts say sleep, diet, and exercise are some of the ways to slow down immune system aging.

Why does our immune system tend to grow weaker as we age?

A new study supports what immunologists have long suspected: A key stressor to our immune system as we age may be stress itself.

“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,” Erik Klopack, Ph.D., a lead author of the study and a postdoctoral scholar at the Leonard Davis School of Gerontology at the University of Southern California, told Healthline.

“Our study suggests that social stress may accelerate immune aging,” he said.

Those who study immunity and aging – called immunosenescence – have long known that as people age, many see a decrease in immune protection.

However, Klopack said why the immune system declines more rapidly in some people has yet to be understood. That’s why he launched this study.

Our bodies build armies for us all our lives, with soldiers called T cells.

T cells are born “naïve,” Klopack said, and as they mature, they hang out in our bodies and wait for a call to action. When activated, they latch on to a virus or other infection that may be trying to harm us.

T cells can become “memory T cells,” which are on the ready to fight these infections again. They can also age into “terminally differentiated” T cells that can go on to have a potentially negative impact on other cells.

What this study found, Klopack said, is that while all people tend to have less naïve cells and more differentiated cells as they age, stress seems to increase that trajectory.

In a time when stress seems to be coming from every direction – pandemic challenges, gas prices, political unrest, extreme weather – Klopack believes digging deeper into this could help society find keys on how to keep a constantly increasing aged population healthier.

“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,” he said.

It’s such a general term, but experts tend to break stress down into two categories: Psychological and physical.

The physical includes everything from weight, activity level, and eating habits to sicknesses and physical injuries.

The psychological can rise from life challenges, discrimination, emotional challenges and mental health battles.

Either way, Dr. Gregory A. Poland, an infectious diseases expert and head of the Mayo Clinic’s Vaccine Research Group, says the answer isn’t removing all stressors.

Rather, he told Healthline, it’s balance.

“Think of stress as an upside-down U curve,” he said.

The top of the U is the ideal balance. One side plunges you into too much stress; the other is too little.

“It’s the Goldilocks phenomenon,” he said. “You need just enough stress; not too much and not too little.”

And even that, Poland said, needs to be looked at over the long term, not in a moment.

For instance, he said, finals week in school is stressful but also short-lived.

“That’s unlikely to have any long-term impact (on your health and immune response),” Poland said.

But too much stress over a long time does seem to impact your immune response, he explained.

Klopack said while this information is helpful, now may be an ideal time to dig deeper.

“Interventions to reduce stress and/or build up resilience and coping tools could help slow immune aging, potentially helping address age-related health inequalities,” he said.

The good news here, experts say, is that responding to this information is doable.

“There is a lot we can do around this,” Poland said. “We are the captains of our own ship.”

Poland said the Goldilocks phenomenon holds true in battling stress as well.

For instance, if your eating habits or weight are stressors, it’s not always the solution to swing too far the other way.

The first step is knowing that people who are aging have a weaker immune response.

“I’m 67,” Poland said. “I don’t have the naïve T Cells my kids have.”

But, he added, healthy living and some extra focus on stress in your life can help.

“There’s a lot we can do,” he said. “We are not helpless victims.”

Klopack said he hopes that is the first thing the public gleans from this study.

If only we could look up to the sky, shout “Serenity now!” and be stress-free.

But, Poland said, that takes effort and attention.

For the physical, he said, “This sounds silly but, grandma turned out to be mostly right. The number one thing we can do is get plenty of restorative sleep.”

A good first step, he said, is stopping the common habit of looking at social media just before going to sleep.

He also suggests working on proper nutrition.

“The American diet (in general) is horrible. High in fat, sugar, processed. It’s just not good,” he said.

Tweaking that, being of a healthy weight, and getting moderate and regular exercise is key, Poland noted.

But again, he added, swinging too far the other way is a stressor, too.

“It’s all that upside-down U,” he said. “Moderation.”

For psychological stress, both Klopack and Poland say finding community and support is key.

“Deal with that stress by first of all recognizing what it is and how it is affecting you,” Poland said.

“Then join someone in that,” he said, “For instance, a therapist.”

Klopack said he and fellow researchers intend to study the issue more, including taking a look at how stress over a lifetime might impact immunity.

“Once new waves of data become available, we will be able to look at the change in these cell percentages over time, and I think that will be very exciting,” he said.

“We are also looking at stress experienced across the life course, including in childhood. There is evidence from other research that childhood adversity can affect adult health, so it is likely that it also affects immune aging,” he added.

Until then, Poland said, those who are aging can know they already can take action by working on balancing their physical and psychological health.

“If you do that, then you have done more than any drug we can ever create,” he said,