Mortality rate associated with sleep duration and disorders.




Archives of General Psychiatry

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Consumer Data: Insomnia, Sleep Disorders
Professional Data: Insomnia, Sleep Disorders


Insomnia is not a disease unto itself but a condition associated with a number of different physical and emotional disorders. The incidence of insomnia is higher among people with chronic illnesses such as hyperthyroidism, kidney trouble, multiple sclerosis, and Alzheimer's disease. Pregnancy, alcohol intake, stress, and depression are also leading causes of insomnia.

Sleep is one of the most mysterious of all human activities. Exactly what happens during sleep is still not completely understood. By studying brain wave patterns, sleep researchers have identified four separate stages in a normal period of sleep. Stage 1 begins when we first fall asleep. Stage 1 is light sleep. Muscles relax and the heart slows down in stage 1. During stage 2, the heart rate increases. Stage 2 sleep is called REM sleep because of the rapid eye movements that occur during this stage. The autonomic nervous system is active in REM sleep, causing rapid breathing and increased stomach acid secretion. Stage 2 is the period when we dream. During deep sleep (stages 3 and 4), no dreaming occurs. In a normal sleep period, a person cycles from stage 1 to stage 4 in about 90 minutes.1 Waking after one full sleep cycle is complete is common among the elderly and small children.

A recent study published in the Archives of General Psychiatry questioned participants of the Cancer Prevention Study II about their sleep duration and problems. Beginning in 1982, researchers determined whether these sleeping issues were associated with mortality. They controlled the results for demographics, health issues, and medication use among others. Over 1 million men and women contributed to this study, ranging in age from 30 to 102 years. Those who slept more than 8 hours a night and those who slept less than 6 hours, illustrated an increased mortality risk compared to those who slept 7 hours who had the lowest risk. Insomnia was not associated with this risk. In addition, people who used sleeping pills had an increased mortality hazard. The authors concluded, "Patients can be reassured that short sleep and insomnia seem associated with little risk distinct from comorbidities. Slight risks associated with 8 or more hours of sleep and sleeping pill use need further study."2


1. Freeman Clark JB, Queener SF, Burke-Karb V. Pharmacologic Basis of Nursing Practice. St. Louis: Mosby; 1993.
2. KripkeDF. Mortality Associated With Sleep Duration and Insomnia.Arch Gen Psychiatry. Feb 2002;59:131-136.