The higher the temperature goes above the 'normal' 37 degrees C (98.6 degrees F), the more the body speeds up its natural defences against tumours, wounds and infections.
Conversely, a low body temperature of around 34 degrees C—which routinely happens when we sleep—can trigger inflammatory processes such as heart disease, which would explain why shift workers or people who suffer from frequent jet lag or insomnia are more prone to inflammatory diseases. Our 24-hour body clock can cope with the natural drop in temperature when we sleep, but the risk of inflammatory disease and cancer rises when it is low for longer periods.
The effects of temperature on health could also explain why cold and flu epidemics are more prevalent in the winter months in the northern hemisphere, say researchers at the Universities of Warwick and Manchester.
A raised body temperature kick-starts the release of a protein, A20, that helps protect the body from inflammatory diseases and cancer. Even small rises in body temperature helps the body's defence systems, the researchers found.
The research echoes a discovery made some years back that found that people who had had a high fever in the previous five years were less likely to develop cancer.