Many working days are lost to colds

Scientists say they have the first proof that there really is a link between getting cold and catching one.

Staff at the Common Cold Centre in Cardiff took 180 volunteers and asked half of them to keep their bare feet in icy water for 20 minutes.

They found 29% developed a cold within five days, compared with only 9% in the control group not exposed to a chill.

Mothers can now be confident in their advice to children to wrap up well in winter

Prof Ron Eccles, Common Cold Centre

Professor Ronald Eccles, director of the centre, said the study had shown, for the first time, a scientific link between chilling and viral infection - something previously dismissed by other studies.

"When colds are circulating in the community, many people are mildly infected but show no symptoms," Prof Eccles said.

"If they become chilled, this causes a pronounced constriction of the blood vessels in the nose and shuts off the warm blood that supplies the white cells that fight infection.

"The reduced defences in the nose allow the virus to get stronger and common cold symptoms develop.

"Although the chilled subject believes they have 'caught a cold' what has, in fact, happened is that the dormant infection has taken hold."

The Common Cold Centre, at Cardiff University, is the world's only centre dedicated to researching and testing new medicines for the treatment of flu and the common cold.

The volunteers in the study were recruited during the peak common cold season - October to March.

Cold noses

While half sat with their feet in chilled in ice-cold water for 20 minutes the others had their feet in an empty bowl.

The research findings published in the medical journal, Family Practice say the fact that common colds are more prevalent in the winter could be related to an increased incidence of chilling causing more clinical colds.

But another explanation could be our noses are colder in winter.

"A cold nose may be one of the major factors that causes common colds to be seasonal," Prof Eccles explained.

"When the cold weather comes, we wrap ourselves up in winter coats to keep warm, but our nose is directly exposed to the cold air.

"Cooling of the nose slows down clearance of viruses from the nose and slows down the white cells that fight infection.

"Mothers can now be confident in their advice to children to wrap up well in winter."