Effects of shift work and extended hours

Shift work and extended working hours can both impact on fatigue. Long hours and shift work patterns that disrupt the body's circadian rhythms often result in workers becoming fatigued.

Shift work

Shift workers as a group tend to get significantly less sleep than those who work equivalent hours that do not intrude on the typical sleep period (11pm - 7am). Sleep during the day is usually of poor quality due to circadian disruptions and environmental factors such as daylight, traffic and household noise.

Extended working hours

Extended working hours, particularly for shift workers, adversely affect the amount of time available for sleep and social activities. As work hours increase, the individual compensates by reducing the amount of time available for sleep and other activities. When a person works more than 48 hours within a week, the increased competition between sleep and other activities results in sleep of a limited quality and length. The individual begins to accumulate a sleep debt, which causes fatigue levels to rise, and affects health and safety.