Adult short sleepers habitually get 5-6 or fewer hours of sleep per 24 hours, without impairment in daytime functioning.11 Their sleep is typically unbroken and, although short, is not a result of voluntarily restricted sleep.12 In children, short sleepers are those who get three hours or less than the norm for their age group.13
About four percent of adults in the United States report sleeping five or fewer hours per night. This number may be an over-estimate, however, as it includes people with behaviorally-induced insufficient sleep syndrome as well as those who suffer from insomnia or mania.14
Short sleepers have similar absolute amounts of slow-wave sleep (SWS) as do normal sleepers, while their amounts of stage 1, 2 and REM sleep are lower than normal.15 Because overall sleep time is short, the normal absolute amounts of SWS result in a higher percentage of SWS per night. Some studies suggest that, compared to long sleepers, short sleepers have an inherently different circadian rhythm (i.e., an internal clock that calls for a shorter-than-usual biological night).16
Short sleepers are considered to be psychologically normal and are typically described as efficient, not prone to worry, possibly somewhat hypomanic.17,18 They may seek help from a sleep center because others worry that they are not getting enough sleep.
By definition, short sleepers have no impairment in daytime functioning; therefore, treatment is neither typical nor required.
- 11Thorpy MJ, “Classifications of Sleep Disorders,” In Kryger M, Roth T, Dement W (ed.), Principles and Practice of Sleep Medicine (5th Edition), St. Louis: Elsevier Saunders, page 687.
- 12Aeschbach D, Cajochen C, Landolt H, Borbely AA. Homeostatic sleep regulation in habitual short sleepers and long sleepers. Am J Physiol. 1996;270:R41-53.
- 13Thorpy MJ, “Classifications of Sleep Disorders,” In Kryger M, Roth T, Dement W (ed.), Principles and Practice of Sleep Medicine (5th Edition), St. Louis: Elsevier Saunders, page 687.
- 14Kripke DF, Garfinkel L, Wingard DL, Klauber MR, Marler MR. Mortality associated with sleep duration and insomnia. Arch Gen Psychiatry. 2002;59:131-136.
- 15American Academy of Sleep Medicine. International Classification of Sleep Disorders, 3rd edition: Diagnostic and Coding Manual. Darien, I: American Academy of Sleep Medicine; 2014.
- 16Aeschbach D, Sher L, Postolache TT, Matthews JR, Jackson MA, Wehr TA. A longer biological night in long sleepers than in short sleepers. J Clin Endocrinol Metab. 2003;88:26-30.
- 17Hartmann E, Baekeland F, Zwilling GR. Psychological differences between long and short sleepers. Arch Gen Psychiatry. 1972;26:463-468.
- 18Monk TH, Buysse DJ, Welsh DK, Kennedy KS, Rose LR. A sleep diary and questionnaire study of naturally short sleepers. J Sleep Res. 2001;10:173-179.