Ever feel like you've been hit on the head after a bad night's sleep? According to scientists, the thought isn't as far-fetched as it seems.
A study found going without sleep for just one night causes changes in the brain similar to those that occur after a blow to the head.
The researchers said the healthy young men examined in the study showed a spike in the same chemicals which indicate brain damage.
Professor Christian Benedict, of Uppsala University, Sweden, explained that the chemicals NSE and S-100B are biomarkers for brain damage, such as concussion.
He said: 'What we found was their levels in the blood rose in the group that went without sleep for a night.This was not to the extent that would happen after a head injury, for instance, but it was still significant.