Nightmare that won’t go away

IT is enough to make you wake up in a cold sweat: the nightmare you had last night is likely to recur next week.

That is because we suffer from ‘ dream lag’ in which a dream, or nightmare, is repeated five or seven days after we initially have it, scientists say.

Mark Blagrove, a sleep scientist at Swansea University, said: ‘ We often tend to dream about what happened yesterday.

‘You then stop dreaming so much of what’s happened, but after about five days you start dreaming of it again.’

This is more likely to occur after an emotive event, suggesting it takes the brain up to a week to process the information.

Happy events may trigger dream repeats – but so may horror movies, the British Science Festival in Swansea heard.

Research shows that discussing dreams makes us feel we have gained an insight into our lives, Professor Blagrove said.