Shift Work and Sleep

Most shift workers have at least occasional sleep disturbances, and approximately one-third complain of fatigue (Åkerstedt, 1995a, 1995b, 1995c). Older shift workers appear to have more sleep-related difficulties than do younger workers, but no gender differences have been found (Harma, 1993). Night shift workers typically get 1.5 fewer hours of sleep per 24 hours as compared with day workers. The midnight to 8 a.m. shift carries the greatest risk of sleep disruption because it requires workers to contradict circadian patterns in order to sleep during the day (Kessler, 1992).

Investigations have demonstrated that circadian phase disruptions caused by rotating shift work are associated with lapses of attention, increased reaction time, and decreased performance (Dinges et al., 1987; Hamilton et al., 1972; Williams et al., 1959). A study of hospital nurses reached similar conclusions based on “real world” experiences. Rotating shifts (working four or more day or evening shifts and four night shifts or more within a month) caused the most severe sleep disruptions of any work schedule. Nurses on rotating schedules reported more “accidents” (including auto crashes, on-the-job errors, and on-the-job personal injuries due to sleepiness) and more near-miss crashes than did nurses on other schedules (Gold et al., 1992). About 95 percent of night nurses working 12-hour shifts reported having had an automobile accident or near-miss accident while driving home from night work (Novak, Auvil-Novak, 1996).

Employee Behavoioral Steps

Shift workers themselves can take steps to reduce their risks of drowsy driving by planning time and creating an environment for uninterrupted, restorative sleep (good sleep hygiene) (Minors, Waterhouse, 1981; Rosa, 1990). Shift workers who completed a 4-month physical training program reported sleeping longer and feeling less fatigue than did matched controls who did not participate in the program. However, individual response to the stresses of shift work varies (Harma, 1993), and the background factors or coping strategies that enable some workers to adapt successfully to this situation are not well defined. The behavioral steps discussed earlier for younger males also seem reasonable for reducing risk in this population. Nurses working the night shift reported using white noise, telephone answering machines, and light-darkening shades to improve the quality and quantity of daytime sleep (Novak, Auvil- Novak, 1996).

Using bright light treatments

Several studies show that timed exposure to bright light has been successful in helping shift workers and those suffering from jet lag adapt to and overcome circadian phase disruption (Czeisler et al., 1990; Stampi, 1994). This approach promotes longer, uninterrupted sleep, which may help reduce sleepiness on the job and behind the wheel. The panel did not find data linking such treatment to changes in rates of crashes or industrial accidents.

from NCSDR/NHTSA EXPERT PANEL ON DRIVER FATIGUE AND SLEEPINESS "Drowsy Driving and Automobile Crashes"