July 19, 2022
Have you ever wondered why some people look older or younger than their chronological age? Or have more or less chronic health problems than people of similar age? It all has to do with senescence – or biological aging.
It is known that as we age, the cells and tissues in our body, as well as our immune system, gradually deteriorate. The aging of the immune system is called immunosenescence, and has been linked to an increased risk of cancer and cardiovascular disease. It also may play a role in older people's less effective response to vaccines.
In a recent study, researchers suggest that stress surrounding different social situations can increase immune system aging.
To explore why people with the same chronological age can have different immunological age, researchers analyzed data from the Health and Retirement study, a large National Institute on Aging survey of U.S. adults over age 50. The participants were asked about the different types of stressors they experience, including loss of a job, discrimination, a family member's life-threatening illness and financial worries.
The researchers also collected blood from a sample of participants so they could count the number of different types of immune cells present. Of the 5,744 participants who completed the survey and provided a blood sample, those who experienced more stress had a lower proportion of fresh or "naive" T cells that are needed to combat invaders the immune system has never faced before.
They also had a larger proportion of older or "late differentiated" T cells, which have difficulty fighting off invaders and are more likely to trigger harmful inflammation. Overall, these participants had a more aged immune system.
The study also found that certain factors can influence the interplay between stress and immune aging. Eating a healthy diet and exercising regularly can counteract the impact of stress on the immune system, while exposure to a common asymptomatic virus — cytomegalovirus — is known to accelerate aging of the immune system.
Once infected, the body retains the virus for the rest of a person's life and stress can cause flare ups and more wear and tear on the immune system. It can also increase chronic inflammation, which increases the risk of age-related diseases, such as cancer and cardiovascular disease.
“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, 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.
The researchers emphasized that the study couldn't establish direct cause and effect. Therefore, more research is needed to confirm the impact stress has on the immune system. The findings make sense when the links between chronic stress and certain health conditions – such as asthma, ulcers, heart attack and stroke – are considered.
Previous studies have found that stress can speed up the aging of the immune system and increase chronic inflammation throughout the body. Scientists continue to show that age-related changes to the immune system not only impacts risk for disease, but also mortality risk.
The good news is that there are ways to slow down immune aging by improving lifestyle behaviors such as diet, smoking and exercise, and by learning healthier ways to cope with stress.
Mental health experts agree that the best way to manage stress is to stay active and disconnect from electronics every now and then. Carving out time for self-care, such as taking a long bath, eating healthier, or taking up yoga or meditation, can also help.
If work is a main stressor, try improving your work-life balance by leaving work at work. Being open to a new job or career change should also be considered if that's what's best for your health, experts say.
If you are still struggling, never afraid to ask for help – the goal shouldn't be to eliminate stress completely, but to manage it in a healthy way.