Running for just five to 10 minutes a few times a week could add three years to your life, researchers have found.
They say gentle exercise is as important for good health as stopping smoking.
A study over 15 years of 55,000 people aged between 18 and 100 found that joggers overall were 30 per cent less likely to die during the period than couch potatoes. They were 45 per cent less likely to die of a heart attack or stroke.
But those who only took a gentle trot three times a week cut their chance of death from a heart attack or stroke by 61 per cent, slightly more than those who ran twice a week.
The findings, in the Journal of the American College of Cardiology, show that even a small amount of exercise is beneficial. The biggest reduction in mortality was seen in the group doing a little exercise compared with those who did none. When researchers looked at regularity of exercise, they found that joggers who went out three times a week cut the chance of death from a heart attack or stroke by 61 per cent compared with non runners.
Considered by distance, they found that those who jogged up to six miles a week cut the risk by almost 60 per cent. They lived three more years.
However, the group that covered more than 20 miles a week was only 20 per cent less likely to die of a heart attack or stroke than those who stayed on the sofa.
The government recommends that everyone should do three hours of exercise a week.
But Dr Duck-chul Lee, of Iowa State University, the lead author of the study, said people who ran less than an hour a week had the same benefits as those on the track for more than three hours a week.
When they looked at persistence, the researchers found those who kept up their running for six years on average had the most benefits. They had a 29 per cent lower risk of dying and a 50 per cent lower risk of death from heart disease or stroke.
Dr Lee said: "Running may be a better exercise option than more moderate intensity exercises."
Oliver Monfredi, of the University of Manchester, said the study showed any exercise was better than none. He said: "Getting your heart rate up on a regular basis is better than being a couch potato."
The Telegraph, London