Chronic training strengthens immune defenses in older adults
Regular long‑term endurance exercise does more than build muscles, lungs, and the heart. New research shows that decades of sustained activity can also train the immune system, enhancing how immune cells respond to threats. In a study focused on older adults with a history of endurance training, scientists found that natural killer (NK) cells—the rapid responders against viruses and diseased cells—were more adaptable, less inflammatory, and metabolically efficient. This finding adds a crucial piece to the puzzle of healthy aging and immune resilience.
The study at a glance
Conducted by an international team and supported by FAPESP, the study analyzed NK cells from nine individuals with an average age of 64. Participants were divided into two groups: those with endurance training histories and those who were untrained. NK cells are a frontline component of the immune system, tasked with identifying and destroying infected or transformed cells, including certain cancers. The researchers explored how these cells functioned under inflammatory stress and how efficiently they used energy—two critical factors in immune performance.
Key findings: better function, less inflammation
Compared with non-athletes of the same age, the trained older adults showed several favorable immune traits. Their NK cells were better at handling inflammatory challenges and demonstrated greater metabolic control. In practical terms, this means a more balanced immune response, with fewer inflammatory markers and more anti‑inflammatory signals. The net effect is a more prepared immune system that resists the kind of chronic, low‑level inflammation often seen with aging.
How endurance training modulates the immune response
Researchers also assessed how NK cells from trained versus untrained older adults reacted to pharmacological blockers that interrupt signaling pathways linked to energy use and adrenaline, such as propranolol and rapamycin. Even when these pathways were blocked, NK cells from trained individuals maintained robust function, while those from untrained individuals showed signs of exhaustion or impaired inflammatory response. This suggests that long‑term endurance training fosters immunometabolic adaptations that keep NK cells flexible and efficient under stress.
What does this mean for aging and disease prevention?
The study contributes to a growing body of evidence that physical activity can shape immune aging. As Dr. Luciele Minuzzi noted, the findings indicate that endurance exercise helps NK cells become more mature and energetically prepared to respond to inflammatory or pharmacological challenges. Professor Fábio Lira added that while several factors influence immunity—sleep, diet, vaccination, stress, and drugs—consistent endurance training appears to be a potent, natural modulator of immune function over time.
Older athletes vs. younger athletes: a different inflammatory balance
In a parallel set of investigations, researchers compared master athletes (older adults with a long history of training) to younger athletes. After an acute exercise session, both groups showed increased inflammatory signals when blood was stimulated with a pathogen, but the increase was more pronounced in younger athletes. Master athletes demonstrated a more controlled inflammatory response, suggesting that lifelong training teaches the body to manage inflammation more efficiently. This balanced response is linked to healthier aging and a lower risk of chronic inflammatory diseases.
Implications for public health and personal practice
The emerging picture is clear: regular endurance exercise can shape the immune system’s defense strategies across the lifespan. While diet, sleep, vaccination, and stress management remain important, decades of sustained physical activity appear to confer a distinct immunometabolic advantage. For individuals seeking healthy aging, incorporating consistent endurance activities—such as brisk walking, cycling, swimming, or running—may help keep the immune system resilient against infections and chronic inflammatory states.
About the research
The study, part of a larger project led by São Paulo State University (UNESP) and conducted with international collaboration, underscores the value of long‑term physical activity in moderating immune aging. The work was supported by FAPESP and published in Scientific Reports, reflecting a growing scientific consensus: exercise is a powerful, practical tool for healthier aging and stronger immune defenses.
