Commuters who catch buses to work walk nearly 300 miles a year, a report has revealed.
Passengers walk an average of 0.8 miles each day to and from bus stops between their homes and offices, according to a study of more than 400 journeys across Britain.
Dr David Lewis, who carried out the research, said: "Someone who travels by bus daily will walk almost 460km (286 miles) per year - that's equivalent to walking 11 marathons.
"This would be of substantial benefit to the two thirds of British adults who, according to the 2010 Health Survey, do not achieve the recommended levels of exercise.
"This study clearly demonstrates that using the bus instead of the car could enhance both personal and national wellbeing."
His research was commissioned by Greener Journeys, a body representing Britain's biggest bus companies.
The group will on Monday present a report to MPs helping to shape Government transport policy.