As people get older, they experience a phenomenon called immnosenescence, a natural decrease in immune system reactivity and responsiveness leading to weaken immunity with older, more fatigued white blood cells and less readily knew ones. This phenomenon lead to many ailments that people of advanced age experience.

Published in Proceedings of the National Academy of Sciences, researchers from the University of Southern California examine the effects of stress on the immune system.

For their study, they analzyed and cross-referenced data from the University of Michigan’s Health and Retirement Study, a longitudinal study looking at economic, health, family status, and support systems of older Americans. From this study, they analyzed social stress responses from 5,744 adults over 50 years old. The participants answered a questionnaire designed to assess their experiences with different kinds of stress including social, chronic, acute, lifetime, daily, etc. The also gathered blood samples from the participants.

The authors found that people with higher stress scores had “older” immune profiles such as less fresh white blood cells and more worn-out, older ones. They found that this association remained even when they controlled for factors like education, smoking, alcohol use, BMI, and race/ethnicity.

However, the relationship between stress and immune-age less associated and unraveled when they controlled for poor diet and lack of exercise.  Lead author, Erick Klopack teased from this, “what this means is people who experience more stress tend to have poorer diet and exercise habits, partly explaining why they have more accelerated immune aging.”

So as we get older, we can still help our immune system to stay younger by eating healthy and exercising. Duh.

Stress, while not necessarily a bad thing because it can be an excellent teacher and test of wisdom, is inevitable in life and its negative effects dampened by healthy eating and exercise.

Take away, when you’re stressed and don’t feel like you want to healthy or exercise, those are the times when you need to do it more than ever and condition yourself to do so.

ET Klopack et al. Social stressors associated with age-related T lymphocyte percentages in older US adults: evidence from the US Health and Retirement Study. Proceedings of the National Academy of Sciences.  DOI: 10.1073/pnas.2202780119