I just never know if it's acceptable to say "old wives' tales" any more. The Guardian has an article about the scientific basis for what it calls "granny's nostrums" about activities that can increase one's chances of catching a cold; in particular not wrapping up warm. The experiment itself sounds pretty funny, since it involved getting ninety volunteers to spend 20 minutes with their bare feet in iced water. You can read about the details and numbers in the articles, but the possible explanations for a connection are described as:
"When colds are circulating, many people are mildly infected but show no symptoms," said Professor Eccles [Ron Eccles, of the Common Cold Centre at Cardiff University], whose findings are published in today's issue of Family Practice magazine. "But 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. "Although the chilled subject believes they have 'caught a cold', what has in fact happened is that the dormant infection has taken hold." But they also suggested that another explanation could be that our noses are colder in the winter. Prof Eccles said: "A cold nose may be one of the major factors that causes common colds to be seasonal. "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."
This is what leads to the following sage advice
Parents should feel confident in telling children to wrap up warmly this winter, the researchers say - though a nose-protecting garment, possibly like the one worn by Harry Potter, would be a useful fashion accessory.
