For most people, summer involves numerous daily shifts between scorching outdoor heat and frosty air-conditioned interiors. But does exposing the body to extreme temperature swings make people sick? Professor Ron Eccles, director of the Common Cold Centre at Cardiff University in Wales, which performs clinical trials for treatments for coughs, colds and flu, explains why keeping a sweater at work isn't such a bad idea.

Chill Defenders

As warm-blooded animals, humans are hard-wired to keep our body temperature at around 98 degrees...