Boosting levels of a key chemical in the brain could help us overcome jet lag twice as quickly as normal, scientists claim.
A study found that mice were able to adjust to a new time zone more quickly if they had been given an injection of the molecule, known as VIP, the previous day.
Finding a way of boosting the chemical naturally, rather than via a jab, could lead to a new therapy for jet lag in jumans, researchers said.
VIP, or vasoactive intestinal polypeptide, was already known to play a key role in keeping the brain's biological clock on time, but the scientists from Washington University in St Louis discovered that higher doses had the reverse effect.
Instead of keeping the body even more tightly tied to the normal schedule of day and night, large amounts of VIP threw the body clock completely out of rhythm.
This loss of synchronisation prompted brain cells to react twice as quickly to shifts in light conditions as they usually would, the researchers reported in the Proceedings of the National Academy of Sciences journal.
They compared the effect to whacking a flickering analogue television to unscramble the picture.
Prof Erik Herzog, who led the study, said: "We found that in mice we could cut 'jet lag' in half by giving them a shot of VIP the day before we 'flew them to a new time zone,' by shifting their light schedule.
"We're taking the system the brain uses to entrain to changes in the seasons and goosing it a bit so that it can adjust to bigger shifts in the light schedule."
Dr Jonathan Johnston, a reader in Chronobiology and Integrative Physiology at the University of Surrey, said it was "unclear" whether the findings could help minimise jet lag in humans.
“The body's master clock is found in a part of the brain called the SCN (suprachiasmatic nuclei)," he explained.
"First, VIP is used by other parts of the body and so a drug would need to be specific to the SCN. Second, jet lag symptoms are thought to result from other clocks in the body responding more slowly than the SCN to a new time zone. It would therefore be more important to help these other clocks respond faster.”