Walk to Work week, which lasts until Friday, is part of health magazine Top Sante's national campaign to reduce the risk of heart disease in women.

A survey commissioned by the magazine and Bupa found that half of full-time working women spent 50 hours each week behind a desk.

It also revealed that 52% found it ''totally impossible'' to fit exercise into their working day.

Eight out of 10 women said they never walked to work and 66% said they took no regular exercise.

Top Sante editor Sharon Parsons said: "The idea is to help women naturally incorporate some exercise into their daily routine without having to make time for lengthy sessions at the gym.

''Walking briskly for about 20 minutes three or four times a week will greatly improve your cardiovascular fitness, help trim your body of excess fat and shape up your mind."

Research has shown that more than half of all women in the UK are overweight with two in 10 classified as being obese. One in five will die of heart disease.

The campaign is supported by the British Heart Foundation.

Belinda Linden, head of medical information for the British Heart Foundation, said: ''Walking to or from work is a brilliant concept, because if exercise doesn't involve too much effort and is built in to a person's everyday routine, they're more likely to keep it up."