Intensity of exercise matters far more than duration, found Danish scientists who studied the health of 4,000 people for a decade.

Those who went on a fast walk daily were at half the chance of having a heart attack or stroke as those who didn’t. Jogging daily cut the odds by 40 per cent.

But those who said they walked for an hour at a leisurely pace had just the same risk as those who were largely inactive.

The research compared the likelihood of developing what is termed metabolic syndrome – a cluster of conditions including high cholesterol, obesity and high blood pressure – among 3,968 people aged 21 to 98. The participants were volunteers in the Copenhagen City Heart Study,

People with metabolic syndrome have a much higher risk of heart disease and stroke in middle and old age.

However, they also found: “Light physical activity and even more than one hour of walking daily did not confer protection against metabolic syndrome.”

Maureen Talbot, Senior Cardiac Nurse at the British Heart Foundation, said: “This study reminds us that it is only physical activities that leave us feeling warm or breathing more heavily that are good for our health.

“Jogging or walking briskly makes the heart beat faster – exercising the heart muscle – and we should all try to do activities each day which get the blood pumping.

“So if you want to make the walk to work or to the shops part of keeping your heart healthy then try turning it from a leisurely stroll into a power walk to get the benefits.”