Dian Griesel and her brother Tom Griesel, who wrote "TurboCharged: Accelerate Your Fat Burning Metabolism, Get Lean Fast and Leave Diet and Exercise Rules in the Dust," say the body cycles through the five known sleep stages four or five times a night.
The first four stages are key to maintaining healthy metabolism, learning and memory, but the fifth, rapid eye movement sleep is important for regulating mood and forming emotional memories, the authors say.
Regularly miss a cycle or two and brain function, immune system and heart health will suffer, the Griesels say.
"Insufficient sleep will make it difficult to function," the Griesels say in a statement. "Most of us require at least 8 [hours] for optimal function and health."
In their book, the Griesels says late night TV, stimulants, meals, work schedules and the proliferation of ambient light all throw off our natural circadian rhythms -- disrupting the normal production of melatonin, natural sleep hormone.
A national survey reported 23 percent of U.S. adults had trouble concentrating because of fatigue, 18 percent had trouble remembering things, 11 percent had difficulty commuting or driving, 38 percent admitted to unintentionally falling asleep during the day and almost 5 percent say they fell asleep or nodded off while driving during the prior 30 days, the Centers for Disease Control and Prevention reports.
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