The risk of a stroke peaks in the early evening and early morning, according to research published today.

Scientists at the Iwate Medical University in Japan have found that strokes occur most frequently between 6am and 8am and 6pm and 8pm. The internal body clock seems to influence the timing, with the lowest risk being when patients are asleep.

The study, published in the Journal of Neurology, Neurosurgery and Psychiatry, analysed data from 12,957 patients who had suffered one of three types of stroke for the first time. The researchers looked for patterns in the wake-sleep cycle.