Think the odd all-nighter is harmless? Think again.
Researchers at Uppsala University and the Karolinska Institute in Sweden have found that just one sleepless night can alter the genes that control the biological clocks in your cells.
The paper, which was published in Journal of Clinical Endocrinology and Metabolism, saw researchers study 15 normal-weight men for two nights, on two separate occasions. Whilst they were allowed to sleep normally on one of the nights, they were made to stay awake on the other, under strict lab conditions.