Regular running can slow the ageing process, say a group of researchers, who added that the physical activity also reduces disability in later life.
The study, which has been published in Archives of Internal Medicine, one of the JAMA/Archives journals, showed that elderly joggers were half as likely to die prematurely from conditions like cancer than non-runners.
They also enjoyed a healthier life with fewer disabilities, the Stanford University Medical Center team found.
"Age-adjusted death rates have reached record lows and life expectancy has reached record highs in recent years, likely due to a combination of behavior and societal changes as well as improved medical and surgical therapies," the researchers said.
"With the rise in life expectancy, it becomes necessary to focus on improving the quality of life and functional abilities as people reach older ages. Regular exercise, including running, may contribute to improved health among older adults,” they added.
For the study, Eliza F Chakravarty, MD, MS, and colleagues at Stanford University School of Medicine, California, surveyed 284 members of a nationwide running club and 156 healthy controls who were recruited from university faculty and staff.
The participants were aged 50 or above the study started in 1984.
They completed a mailed questionnaire annually through 2005, providing information on exercise frequency, body mass index and disability level.
At the beginning of the study, runners were younger, leaner and less likely to smoke than controls.
After 19 years, 81 runners (15 per cent) had died compared with 144 controls (34 per cent). Disability levels were lower in runners at all time points and increased in both groups over time, but less so in runners.
At the end of the 21-year follow-up, in terms of disability, "the higher levels among controls translate into important differences in overall daily functional limitations," the researchers said.
"Disability and survival curves continued to diverge between groups after the 21-year follow-up as participants approached their ninth decade of life,” they added.
Regular exercise could reduce disability and death risk by increasing cardiovascular fitness, improving aerobic capacity, increased bone mass, lower levels of inflammatory markers, improved response to vaccinations and improved thinking, learning and memory functions, the scientists said.