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Plain Language About Shiftwork

July 1997
DHHS (NIOSH) Publication Number 97-145
cover of 97-141

Shift Workers and night workers often are tired and sleepy because of their work schedule. Being overly tired makes it difficult to concentrate, which increases the possibility of errors or accidents. This can be a risk both to the worker and to the public. The stress of shift work also can aggravate health conditions, such as heart disease or digestive disorders.

Working at night makes it difficult to get enough sleep. Sleep after night work usually is shorter and less refreshing or satisfying than sleep during the normal nighttime hours. Brain and body functions slow down during the nighttime and early morning hours. The combination of sleep loss and working at the body’s low-point can cause excessive fatigue and sleepiness. This makes it more difficult to perform well, which increases the risk of accidents. Also, shiftwork can be stressful because of frequent switching from a day to night schedule and because of separation from family and friends. These stresses can be harmful to health.