9781422285770

12

DANGEROUSLY TIRED

According to a poll by the National Sleep Foundation, 60 percent of adult drivers in America have driven a vehicle while feeling sleepy. Almost 37 percent admitted to falling asleep while driving. That means about 117 million people have driven while sleepy, and more than 72 million have actually fallen asleep. Studies have shown that sleep-related automobile accidents kill more young people than accidents linked to alcohol. Sleep deprivation has also contributed to some major disasters. Both the worst nuclear accident in US history (Three Mile Island, Pennsylvania, 1979) and the giant 1989 Exxon Valdez oil spill in Alaska were partly caused by someone who had not had enough sleep.

sleep, which is when people dream, and non-rapid eye movement (NREM) sleep, which does not involve dreaming. In order to feel rested, our bodies need to go back and forth between REM and NREM sleep. This is called the sleep cycle. Most people experience four or five sleep cycles in a normal night’s sleep, although this can vary. The Sleep Cycle: NREM NREM sleep has four stages. Stage 1 is that drowsy state when you move from being awake to falling asleep. Your eyelids feel heavy; your muscles begin to relax; your heart rate and breathing slow; you feel yourself drifting away. Stage 1 sleep