Many people use the clocks going back to gain an extra hour in bed - but a sleep expert says the change can actually leave people tired.
Even such small changes, said Dr Neil Stanley, can disrupt sleep routines and cause semisomnia - low grade exhaustion caused by inadequate rest.
He estimated that it could take three days to fully adjust to the change.
The Norfolk and Norwich Hospital expert said people should set aside time to wind down before going to bed.
"People may feel relaxed and refreshed as they wake up this morning after an extra hour in bed, but it will actually take three days for their body to catch up with this one-hour time shift. "
Source - BBC