An analysis of half a million British tests establishes that 13.30 is the time when students achieve better grades. The circadian rhythm, the biological clock that determines the rhythm of human activity based on the hours of the day, is important in determining how humans are active.
By law, university students in Great Britain can only have one exam a day at pre-arranged times: nine in the morning,13.30 and 16.30. Researchers Alessio Gaggero and Denni Tommasi have used the British higher education system for their study.