April 24, 2025 – Scientists may have discovered the key to healthy aging.
It's called immune resilience, the ability to stay healthy and bounce back after infections like the flu. People with good immune resilience have a 15-year survival advantage over those whose resilience starts to falter, a new study suggests. This is particularly true throughout middle age, but by around 70 years old, everyone's body pretty much becomes less resilient.
"We have similar aging rates, but very different health outcomes, which is what you call healthspan," said study author Sunil K. Ahuja, MD, a professor at UT Health San Antonio and director of the Veterans Affairs Center for Personalized Medicine, South Texas Veterans Health Care System. "The principle of immune resilience is basically the idea that there are some people who have the power to live longer and they get sick less often."
Taking steps to improve your immune resilience during midlife – between ages 40 and 70 – could be crucial for living longer and healthier, the findings suggest.
Improving Your Immune Resilience
Scientists' understanding of immune resilience has evolved a lot in recent years, and the new study builds on previous research by uncovering the role of a specific protein. Ahuja's team found they could measure levels of this protein, which helps regulate the immune system, and link it to a person's immune resilience.
The researchers analyzed data for 17,500 people, including some with health problems like the flu, Alzheimer's disease, heart disease, and serious infections. People with high immune resilience at age 40 – as marked by these protein levels – had a 15.5-year survival advantage through middle age, compared to people with low immune resilience. Basically, their risk of dying sooner was the same as someone 15 years older.
According to the analysis, published Wednesday in the journal Aging Cell:
- Some people maintain strong immune resilience over time.
- Others have a temporary dip in immune resilience but recover.
- And still others have persistent and ongoing immunity losses.
These variations suggest that immune resilience can be changed, setting the stage for researchers to evaluate how lifestyle changes like diet and exercise, or medicine and other treatments, may help people restore or maintain high immune resilience.
Known lifestyle factors that influence immune resilience include healthy eating, exercise, sleep, and stress management. It also helps to take precautions – like handwashing – to avoid getting sick in the first place because your immune resilience may not bounce back.
Results from a group of blood tests could be used as an immune resilience checkup, Ahuja said, noting that he even used these tests during the height of the COVID-19 pandemic to help find out which hospitalized patients needed the most aggressive treatment.
Aging Doesn't Discriminate
Despite lots of variation during middle age, everyone's immune resilience pretty much equalizes around the age of 70, the study showed. The novel finding aligns with life expectancy data. Further, women tended to have higher levels of the protein linked to immune resilience, which also aligns with data that shows women tend to live longer than men.
Research is already underway looking at how these tests can be used to help in both diagnosis and healthy aging, Ahuja said. While this latest study showed that the greatest variation in immune resilience sets in during middle age, other applications may be useful for younger people too.
"If a 25-year-old person came to me and [had test values in the lowest range] for immune resilience, I'd be very concerned," Ahuja said. "I would be looking for whether they have stress, whether they've got cancer, or if they've got some other problem that I'm unaware of."
