A study of 88,140 people released in the British Journal of Sports Medicine last Tuesday discovered that a brisk stroll once or twice a week can reduce the risk of dying from heart attack, stroke or cancer.

The researchers sifted through data collected annually in the United States between 1997 and 2008 for the National Health Interview Surveys. Bo Xi, a professor in the Department of Epidemiology at Shandong University in northern China, led the team.

That data on exercise was then matched against registered deaths through 2011.

It showed that people who exercised 10 minutes to an hour each week had an 18 per cent lower risk of death from any cause.

Two-and-a-half to five hours weekly of such “moderate physical activity” resulted in a 31 per cent reduction in risk. Those who exercised for 25 hours almost halved the risk. But not everyone has that much time to spend on leisure-time exercise.

According to the researchers, heart-pumping and pulse-quickening activities such as biking, running and competitive sports “are more time-efficient than moderate intensity activity.”

For cardiovascular disease alone, there was no added benefit gained by graduating from five to 25 hours.

The authors cautioned that the study was observational. But they cannot draw any firm conclusions about cause and effect. The self-reported exercise data was also a potential weakness.

But the number of people covered by the research helps to compensate for these methodological limitations.