1. Health professionals increasingly recognize the importance of eight hours of sleep a night. Scientists now believe that sleep is the single most important factor for general health, more important than diet or exercise. It is the only treatment that can claim to restore, rejuvenate, and energize both the body and the brain. The third of our lives that we spend asleep has a profound effect on the two-thirds that we spend awake— affecting our mood, memory, alertness, and performance.
2. Studies show that people in the developed world increasingly spend less time asleep and more time at work or commuting. Dr. Karine Spiegel, at the University of Chicago, has found that the average length of sleep in developed nations has declined from nine hours in 1910 to seven-and-a-half hours today. However, we are biologically ill-equipped to function on little sleep; and losing just one or two hours of sleep a night over a long period can have a serious effect on someone’s health.
3. According to Canadian scientist Dr. Stanley Coren, every hour of sleep lost in a night also causes us to drop one I.Q. point the next day. In a week of five- or six-hour nights, the average person’s I.Q. could drop 15 points: thus, a normally intelligent person starts to have a hard time functioning at all.
4. Most sleep experts agree that humans are designed to sleep for at least eight hours, but that this should be in two stages: a long sleep at night and a shorter nap in the afternoon. American companies are paying attention to this and are reporting increased levels of alertness in employees who “power nap” at some point during the afternoon, if only for 20 minutes. The argument is that those who are not sleep-deprived are much more efficient at work.