LONDON - Who sleeps does not fish, says old saying. The longer you sleep and longer you live, it corrects modern science. Or at least it is corrected by a scholar, Professor Matw Walker, director of Center for Human Sleep at Berkeley University, California, now author of "Why we sleep," a book that signals an alarm on new "Sleep deprivation epidemic": it calls it just like it was a contagious virus. "And really, because today's life pushes us to sleep less and less, without taking sufficient account of dangerous effects of phenomenon," warns original professor of Liverpool. Fortunately, for this kind of epidemic re is cure. It is available to anyone and costs nothing: just sleep. Because according to Walker, equation is dramatically simple: less sleep, less alive. In or words, insomnia, want or suffering, shortens life. The number of diseases associated with sleep deprivation, says English scientist, is long and scary: Alzheimer's disease, cancer, diabetes, obesity, mental disorders. "Every aspect of our biological life is affected and conditioned by night-time rest," says scholar. "And unfortunately nobody does enough to change things." Nobody has seen, in fact, signs inside hospitals and outpatient clinics that urge people to sleep more. Instead, author is a priority of our health that we must urgently take into account. The loss of sleep costs British economy 30 billion pounds a year, equivalent to 2 per cent of GDP, Walker estimates, and given size of United Kingdom, similar estimates can be made for or European countries such as Italy, France, Germany. His book suggests that a good "diet" of sleep would be eight hours a night. A goal that many of us seem unattainable. But threshold below which we should never go down, warns Berkeley's professor, is seven hours of sleep per night: those who sleep less risk ir health and consequently less likely to live longer. The problem, Walker recognizes, is that work ethics, as well as from younger age of studio, makes us less and less sleep to do more and more things. And it's not just about working or studying: re is gym, courses of all kinds for adults and children, languages to learn or refine, to silence smart phone that through social networks keeps us awake even when eyelids are y close to eyes like two automatic shutters. Just a few figures to clarify how our relationship with sleep changed. In 1942, less than 8 per cent of population, in Europe and United States, survived with 6 hours of sleep or less per night. In 2017, one person sleeps six hours or less at 6 hours per night: 50 percent. Extraordinary work, longer transport for commuters, multiplying entertainment, anxiety, depression, alcohol and caffeine are all causes of transformation, according to experts. "All enemies of sleep," writes Walker. And n re is anor: "In today's western society, you are ashamed to say that you sleep a lot. Sleeping little is considered a badge of honor, something to boast about. It's embarrassing to admit in public that y sleep eight hours a night. It is a figure of lazy, not to say of abnormal. " Care would refore be simple, but it requires a drastic change of lifestyle. If you suffer from insomnia, or you are forced to sleep little, you are in good company: two thirds of adult population in developed countries sleep less than eight hours a night. That is number of hours of sleep recommended from World Health Organization. Professor Walker in a sense did not find anything: he just put his finger on plague. Or rar on our wide-open eyes when y should be closed, accompanied by a sweet ron-ron.