Irish Examiner View: To sleep, perchance to dream — for seven hours only

Shakespeare was really on to something when he wrote: “Sleep, the main course in life’s feast, and the most nourishing.”

According to a new study, seven hours is the optimum amount of time for adults aged 38 to 73. File Picture

What is the difference between too little and too much? It is one of life’s imponderable questions, but the answer has come a little closer, at least in terms of the subject of sleep, following a survey of half a million adults.

Scientists, writing in the journal Nature Aging, warn that “too little or too much sleep” is likely to cause cognitive problems in the long term and that the optimum dose is seven hours for people who want to keep their minds healthy in middle age and beyond.