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Chest. 2000 Aug;118(2):372-9.

Sleepiness, fatigue, tiredness, and lack of energy in obstructive sleep apnea.

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Sleep Disorders Center and Department of Neurology, University of Michigan, Ann Arbor 48109-0117, USA.



Sleepiness is a key symptom in obstructive sleep apnea syndrome (OSAS) and can be objectively assessed with a multiple sleep latency test (MSLT). We studied the terms that patients prefer to describe their symptoms-sleepiness, fatigue, tiredness, or lack of energy-and how these terms relate to objective findings.




University-based sleep laboratory.


Consecutive OSAS patients referred for diagnostic polysomnography and an MSLT.


Data were obtained from sleep studies and questionnaires.


Subjects included 117 men and 73 women, with a mean (+/- SD) age of 49 +/- 13 years, an apnea and hypopnea rate of 32 +/- 28/h of sleep, and an MSLT mean sleep latency of 7 +/- 5 min. Subjects more frequently reported problems with fatigue, tiredness, and lack of energy than sleepiness (57%, 61%, and 62% vs 47%). When required to select the one most significant symptom, more patients chose lack of energy (about 40%) than any other problem, including sleepiness (about 22%). Objective measures of sleepiness and apnea severity showed little or no association with any symptom, but female gender showed significant associations with each.


Complaints of fatigue, tiredness, or lack of energy may be as important as that of sleepiness to OSAS patients, among whom women appear to have all such complaints more frequently than men. The diagnosis of OSAS should not be excluded based only on a person's tendency to emphasize fatigue, tiredness, or lack of energy more than sleepiness.

[Indexed for MEDLINE]

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