Older individuals who do lots of exercise can prevent their immune systems from declining and protect themselves against infection, scientists say. For the research, scientists from King’s College London followed 125 long-distance cyclists, some of who were in their 80s. They found that some had the immune systems of much, much younger individuals. For example, Prof Norman Lazarus, 82, of King's College London, who co-authored the research and took part in it, was found to have the immune system of a 20-year-old. "If exercise was a pill, everyone would be taking it. It has wide-ranging benefits for the body, the mind, for our muscles and our immune system,” he said. Speaking about the research, Prof Janet Lord, director of the Institute of Inflammation and Ageing at the University of Birmingham and co-author, said people’s immune systems decline at a rate of about 2-3% a year from the age of 20. That’s why older individuals are more susceptible to infections, rheumatoid arthritis and, potentially, cancer. Because the cyclists were found to have the immune systems of much younger people, they have added protection against conditions that tend to affect older individuals. Furthermore, the researchers believe that physically active, older individuals respond better to vaccines, meaning they are also better protected against influenza. The good news is that you don’t need to be a competitive cyclist to reap the benefits. Just being more active and puffing yourself out from time to time can help.