Shift Work Sleep Disorder Signs and Symptoms

Circadian rhythm, which occurs on a 24-hour schedule and is largely influenced by daylight, affects energy levels and alertness. A person's sleep-wake cycle or internal clock helps to determine when he or she is awake and alert, has the most energy, feels tired, sleeps, experiences hunger, etc. When an irregular work schedule disrupts the natural sleep-wake cycle or internal clock, symptoms related to shift work sleep disorder (SWSD) often can result.

The primary symptom of shift work sleep disorder and other circadian rhythm disorders is excessive sleepiness (ES). People who are more tired and less alert than normal are at increased risk for stress-related medical conditions and for accidental injuries. Other symptoms of shift work sleep disorder include irritability, decreased appetite, difficulty concentrating, and memory loss.

Publication Review By: the Editorial Staff at

Published: 15 Apr 2009

Last Modified: 24 Jan 2012