Bedtime 'has huge impact on sport'

Our internal body clock has such a dramatic impact on sporting ability that it could alter the chances of Olympic gold, say researchers.

The team at the University of Birmingham showed performance times varied by 26% throughout the day.

Some aspects of sporting ability were thought to peak in early afternoon but a study in the journal Current Biology suggests each competitor's sleeping habits have a powerful impact.

They took 20 female hockey players and asked them to perform a series of 20m runs in shorter and shorter times.

And they did it at six different times of day between 07:00 and 22:00. For more, please click here