How Sleep Works

Insomnia #3 – Understanding Sleep You spend the third of your life sleeping or at least you should. So what goes on while you are snuggling under the covers? Mark Haltrecht, D.O. Family Practice Doctor NSLIJ Plainview Hospital Most of us think of sleep as dead time and it is actually an active state during which the brain and body regenerate. For this reason, a good night sleep is essential to a good day’s productivity. During sleep the body repeatedly cycles through four stages of non rapid eye movements sleep or NREM and one stage of rapid eye movement sleep or REM. Each of the four stages of NREM sleep can last from five to 15 minutes. During stage 1 of REM sleep you can be awakened very easily. And if you are, you may feel like you have not slept at all. During this first NREM stage, many people experience a feeling of falling which can cause a sudden muscle contraction, known as hypnic myoclonia. Often hypnic myoclonia will cause an abrupt awakening. When the body enters stage 2 of NREM sleep the heart rate slows and body temperature drops. Muscles tightened and then relax again as you prepare to enter deep sleep. Stages 3 and 4 of NREM sleep are also known as slow wave or delta sleep, although, stage 4 is more intense. If aroused during these stages, you may feel briefly disoriented before awakening fully. During the delta sleep stages of NREM, the body repairs and regenerates energy, builds bone and muscle and strengthens the immune system. After the body cycles through its first four stages of NREM sleep, generally 90 minutes after sleep onset, it enters the first course of REM. The first period of REM last for about 10 minutes, and then you begin the cycle again, passing through the four stages of NREM before reentering REM sleep. Each subsequent stage of REM lengthens into the last segment which may last for up to an hour. During REM sleep, the eyes move rapidly in different directions hence the term rapid eye movement. Heart rate and respiration also speed up and become erratic. Dreaming occurs only during REM, as the result of the heightened brain activity in this stage. Paradoxically, during this time, your muscles are paralyzed. To be properly restored and regenerated, the body must repeatedly cycle through all of these stages. Usually for about seven to eight hours at night in an adults. If you have trouble falling asleep or can sleep through the night, if you wake up too early or if you are tired during the day, you may have a sleep disorder. Common sleep disorders include standard insomnia, sleep apnea, narcolepsy, restless leg syndrome, night mares and sleep walking. Because the body needs sleep to properly restore and repair itself, it is vital to get your uninterrupted eight hours. If you are not sleeping as well as you should, please see your doctor. Want to learn more, check out other videos and sources on this site for more information.