Go To Sleep

Demands of work and the lure of night life have reduced the average time spent asleep by one and a half hours during the century, with potentially damaging consequences for health, scientists say today.

While it is usually agreed that sleep is essential for a healthy brain, researchers have found that too little sleep can produce marked biological changes similar to premature ageing and diabetes. They found that the body works better with more than eight hours' sleep. Even fit young men restricted to four hours' sleep a night found that processing and storing carbohydrates and regulating hormones were affected by sleep deprivation.

Prof. Eve Van Cauter and colleagues from the Department of Medicine, University of Chicago, say in The Lancet that people in developed countries had, on average, nine hours' sleep a night in 1910. This has fallen to 7.5 hours "to create maximum time for work and leisure activities".

She said: "We found that the metabolic and endocrine hormonal changes resulting from a significant sleep debt mimic many of the hallmarks of ageing. We suspect' that chronic sleep loss may not only hasten the onset but could also increase the severity of age-related ailments such as diabetes, hyper tension, high blood pressure, obesity and memory loss."

In the study 11 healthy men, aged 18 to 27, received eight hours' sleep for three nights, followed by four hours for six nights and 12 hours for seven nights. They ate the same diet.

It was found that, when subjected to sleep deprivation, they took 40 per cent longer than normal to regulate their blood-sugar levels after a high carbohydrate meal.