In the study, published in the journal Aging Cell, researchers looked at 125 very active adult cyclists who were between ages 55 and 79. The researchers analyzed their blood for markers of T-cells, which are known to help the immune system fight infections.
The study authors then compared the cyclists to people in their same age group who did not exercise regularly, as well as younger adults between ages 20 and 36. Not only was T-cell activity higher in the active adults than the inactive men and women, but the cyclists were also producing the same level of T-cell activity as young adults in their 20s.
“The immune system declines by about 2-3% a year from our 20s, which is why older people are more susceptible to infections, conditions like rheumatoid arthritis and, potentially, cancer,” study author and professor Janet Lord, the director of the Institute of Inflammation and Ageing at the University of Birmingham in the United Kingdom, told the BBC. “Because the cyclists have the immune system of a 20-year-old rather than a 70- or 80-year-old, it means they have added protection against all these issues.”
More research is needed, but the researchers write in the report that aging is complex process that involves many factors like genetics, environment and lifestyle, and that their research suggests that physical activity—or inactivity—can be an important driver in how people age and how well their immune systems function.
The researchers are planning to continue study the cyclists. “Our future studies in this cohort will aim to test immune function, notably the response to vaccination, as a clinical proof of the beneficial impact of physical activity on adaptive immune function in old age,” they conclude.