Researchers are seeking ways to help the body clock reset itself in response to a trans-Atlantic flight, for example, or a night-time workshift.

BBC: Body clock 'set before birth'

Study leader Dr Michael Hastings said in mice who by a quirk of genetics had a 20-hr body clock, they were able to reset the clock to 24 hours by using known compounds that are known to slow down the action of cAMP.

BBC: Body clock reset clue discovered

Sleep therapists correct the syndrome by forcing the advanced phase patients to stay up late and exposing them to bright light around 0230 AM - helping to "manually" reset the clock.

BBC: 'Sleepyhead gene' discovered