As the season of sneezing and grabbing tissues begins with the autumn's first frosts, medical researchers have found that "granny's nostrums" to fend off colds may be scientifically proven.

Ninety volunteers who spent 20 minutes with their feet in bowls of iced water have provided evidence that failing to wrap up warmly is directly linked to falling prey to sore throats and a bunged-up nose.

Although apparently common sense, straightforward connections between chilling and viral infection have been hard to prove, according to the common cold centre at Cardiff University - the world's only centre dedicated to researching and testing new medicines for the treatment of flu and the common cold.

But the latest experiment reinforces theories that existing, latent infection can be activated when parts of the body, particularly the feet and nose, get wet and cold.

Claire Johnson and Ron Eccles from the centre found that 29% of the volunteers developed cold symptoms within five days, compared to 9% of a control group who dangled their feet in empty bowls.

All participants took off their shoes and socks and temperatures were monitored throughout the experiment.

"When colds are circulating, many people are mildly infected but show no symptoms," said Professor Eccles, 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."

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.

中文：

冬天已经悄然来临，对于很多人来说，这也意味着又到了他们频繁的打喷嚏和流鼻涕的季节了，而英国一些医学方面的研究人员近日表示，他们发现那种把身体包裹得密不透风来抵御感冒的传统方法是有科学意义的。

据英国《卫报》11月14日报道，目前世界上唯一一个专门研究和检测各种用来治疗流感及普通感冒的药物的研究机构——英国加的夫大学普通感冒研究中心的科研人员表示，尽管多穿衣服可防感冒早已成为常识，但科学家们却一直很难证明在身体着凉与病毒感染之间存在着直接的联系。但他们最新进行的实验表明，当身体的某些部位（尤其是双脚和鼻子）处于潮湿冰凉的环境里时，原本处于潜伏期的病毒感染会变得活跃起来。

在实验中，所有参与者都脱下鞋子和袜子，而空气温度也受到了全程监控。这些人被分成两组，其中一组志愿者将自己的双脚放到了盛满冰水的盆中，并在里面坚持了20分钟，实验结果充分证明，如果一个人没有使自己的身体完全处于温暖状态下的话，则可以直接导致咽喉肿痛与鼻塞。实验发现，29％的脚踏冰水的志愿者在此之后的5天内出现了感冒症状。

参与研究的加的夫大学的埃克勒斯教授表示：“当冷空气处于循环流动状态下时，很多人会轻微感染上各种感冒病毒，但并未表现出任何症状。但如果一个人已经明显感到寒意的话，那么其鼻子内的血管会发生明显的收缩，此举可阻断那些携带有白血球的温暖血液的前进道路，而白血球正好可以消灭那些感冒病毒。尽管那些被冻着的人认为自己此时刚刚染上感冒，但实际情况却是其体内原先处于潜伏状态的病毒开始发威了。”

但研究人员也提到了对此的另外一种解释，那就是我们的鼻子的温度在冬天会变得较之其它季节更低一些。埃克勒斯教授说：“较冷的鼻子或许是导致普通感冒成为季节性疾病的一个主要原因。在冬季到来时，我们会将厚厚的冬衣裹在身上以驱寒保暖，但却常常将自己的鼻子直接暴露在寒冷的空气中。鼻子着凉使得白血球无法及时投入与感冒病毒作战的主战场，从而延缓了对那些病毒的清除。”

埃克勒斯教授的相关研究成果已经刊登在11月14日出版的《家庭实践》杂志上。研究人员表示，父母们完全可以满怀信心地告诉孩子们，冬天应当多穿些衣服将身体包裹得严严实实的，尤其是那些能使鼻子得到充分保护的服装。