Older people who go running several times a week walk with the same vigour as a typical 20-year-old, a study has shown.
But those who only exercise by walking are likely to tire more easily, researchers found.
Study lead Prof Rodger Kram, from the University of Colorado at Boulder, said: “The bottom line is that running keeps you younger, at least in terms of energy efficiency.”
The study involved 30 healthy volunteers with an average age of 69 who either ran or walked regularly for exercise.
In tests, they were asked to walk on a treadmill at three different speeds, 1.6mph, 2.8mph and 3.9mph.
During the training sessions, measurements were taken of their oxygen consumption and exhaled carbon dioxide.
Leading charity Alzheimer’s Society said it welcomed the research as it is important to highlight the need for older people to exercise more.
Rob Stewart, Alzheimer’s Society media and communications officer for the North East, based at Beacon Centre, Westgate Road, Newcastle, said: “Research shows that what is good for your heart is good for your head.
“While this research didn’t look at dementia, there is a growing mountain of evidence suggesting that there are simple things people can start doing now to reduce their risk of developing the condition, including exercise.
“Research has shown that exercise may also improve memory and slow down mental decline as well as provide opportunities for social interaction. If you’re not a natural runner, don’t fret – moderate exercise including walking regularly can help reduce risk of dementia.
“There are 35,000 people living with dementia in the North East. The best way to reduce your risk of developing dementia is to eat a healthy diet, exercise regularly, maintain a healthy weight and not smoke.”
Volunteers in the study who ran regularly expended the same amount of energy as a normal 20-year-old.
But the amount of energy used by non-runners for walking was typical of older, sedentary adults - about 22% higher than it was for 20-somethings.
Co-author Prof Justus Ortega, from Humboldt State University, California, said: “What we found is that older adults who regularly participate in highly aerobic activities - running in particular - have a lower metabolic cost of walking than older, sedentary adults and also lower than seniors who regularly walk for exercise.
“It’s been known for a long time that as people age, their maximum aerobic capacity, or ‘horsepower,’ declines, and that is true for runners as well. What’s new here is we found that old runners maintain their fuel economy.”
Running is a form of exercise that is accessible for many as almost anyone can don a pair of trainers and run around the streets at a time convenient to them.
Owen Beck, another member of the research team, said: “It was surprising to find that older adults who regularly run for exercise are better walkers than older adults who regularly walk for exercise.
“The take-home message of the study is that consistently running for exercise seems to slow down the ageing process and allows older individuals to move more easily, improving their independence and quality of life.”
The research is reported in the online journal Public Library Of Science ONE.