Coffee has secret trick to stop sleep
By James GallagherHealth editor, BBC News website copyright Thinkstock A cup of coffee in the evening may be keeping you awake for more reasons than you realise, scientists say. Their study, in Science Translation Medicine, showed caffeine was more than just a stimulant and actually slowed down the body's internal clock. A double espresso three hours before bedtime delayed the production of the sleep hormone melatonin by about 40 minutes, making it harder to nod off. Experts said our own actions had a huge influence on sleep and the body clock. One of the researchers, Dr John O'Neill, from the Medical Research Council's Laboratory of Molecular Biology in Cambridge, told the BBC News website: "If you're tired and having a coffee...