Adjusting temperature key to beating jetlag: study

Scientists at Queen Mary College at the University of London found that human biological clocks are driven by alterations in body heat as well as changes in light.

This means putting on extra clothes, drinking hot drinks and standing by a heater could improve the feeling of sleepiness caused by jetlag, the 'Daily Mail' reported.

Alternatively, if you've visited a cold country and return to a hot one, having a cold bath or stripping off could make you feel better.

A study of jet lagged fruit flies showed a group of cells at the back of the brain was more important for clock-synchronisation at warmer temperatures.

The researchers made fruit flies jet lagged by exposing them to daily temperature changes reflecting warmer or colder climates, to understand how temperature affects the circadian clock.

The team discovered that a group of 'dorsal clock cells' found in the back of the fly's brain was more important for clock-synchronisation at warmer temperatures.

But a group of 'ventral clock cells' found further to the front of the brain played an important role at the cooler temperature range.

In addition to their clock function, these cells also act like a thermometer, being more active at certain temperatures.

The research also showed that removing the light receptor Cryptochrome - an important component in synchronising the clock to the daily light changes led to the flies being more sensitive to temperature changes.

"Research on animal and human clocks shows they are fine tuned by natural and man-made time cues. For example, the daily changes of light and temperature, alarm clocks and noise-pollution," Professor Ralf Stanewsky, of Queen Mary College said.

"A wide range of organisms, including insects and humans, have evolved an internal clock to regulate daily patterns of behaviour, such as sleep, appetite, and attention," Stanewsky said.

Biological clocks, which drive circadian rhythms, are found in almost every living organism. In mammals, including humans, these clocks are responsible for 24-hour cycles like alertness and hormone levels, for instance.

The control panel for these daily rhythms is the suprachiasmatic nucleus (SCN), otherwise known as 'the brain's Timex'.

The SCN, located above the roof of the mouth in the hypothalamus, is normally synchronised to local time by light signals carried down the optic nerves.

"Understanding the principles of clock synchronisation could be useful in developing treatments against the negative effects of sleep-disorders and shift-work," said Stanewsky.