GPs should ask all patients how far they walk because it is more important to their health than either weight or blood pressure, say experts.
They warn that a lack of activity causes far more deaths than smoking, obesity or diabetes and urge family doctors to question patients on their exercise habits – particularly walking – and keep a record of them.
If patients admit to walking for fewer than 30 minutes a day they must be urged to do more.
The group of scientists from Canada, America and Australia believe that a lack of exercise leads to many cases of fatal cancers and heart disease.
However, activity can prevent hip fractures and there is evidence it may ward off dementia.
Professor Karim Khan, from the University of British Columbia said: “Activity levels are the most important factor influencing our health.
“They are much more important than our blood pressure or how many times we breathe a minute.
“In the US more people die as a result of a lack of physical activity than smoking, obesity or diabetes. It’s fitness not fatness.”
Professor Khan, whose study is published in the Lancet, added: “Physical activity affects every system. Not getting enough can lead to a range of illnesses including cancers and diabetes.
“You don’t have to be an Olympian. If people take more than 150 minutes exercise a week, including walking, they probably don’t need to worry about it.
“If they take less their doctor needs to be encouraging them to take more.”
Professor Khan said patients could fill in forms about their exercise levels in the waiting room to save GPs time during the appointment.
“Low fitness is a better predictor of mortality than obesity or hypertension, which are health risk factors afforded far greater emphasis than fitness by the media and most health professionals,” he continued.
The researchers are recommending that doctors should record exercise along with patients’ temperature, blood pressure, pulse, and breathing.
At present the Department of Health recommends that everyone takes at least two and a half hours exercise a week – or 30 minutes spanned over five days