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Shift workers can have a more 'normal' schedule
Workers don't need to continuously sleep during day
Night shift workers often are reluctant to sleep days on a strict schedule, even on their days off, and a new study indicates they might not need to.1
Instead, workers might be able to improve productivity with some simple interventions, and they might be able to keep to a more "normal" schedule compatible with night shift and days off.
Twenty-four workers in the study did seven simulated night shifts from 11 p.m. to 7 a.m., interspersed with two days off. An experimental group slept in dark bedrooms at scheduled times, were exposed to five 15-minute intermittent bright light pulses each night shift, wore dark sunglasses when outside, and received outdoor afternoon light exposure. A control group wore lightly tinted sunglasses when outdoors, had normal room light during night shifts, and had unrestricted sleep and outdoor light exposure.
The body clock for the experimental group showed partial adjustment to the night shift schedule, which was compatible with daytime sleep after night shifts as well as late nighttime sleep on days off. The control group showed less adjustment to the night shift schedule, and control subjects that adjusted the least had decreased daytime sleep duration after night shifts.
Work performance was assessed by measuring simple reaction time during night shifts. The subjects in the control group had longer and more variable reaction times, whereas the experimental group performed close to levels seen during the day shift, with fast reaction times with low variability and few or no lapses.
One surprising finding, however, was the number of control subjects whose body clock showed substantial realignment that would promote night shift alertness and daytime sleep, says study author Mark Smith, PhD, a postdoctoral fellow at Rush University Biological Rhythms Research Lab in Chicago.
"These control subjects did not receive any interventions to help their body's clock adjust to the night shifts," says Smith. "But several of them self-selected a schedule of sleep and wakefulness similar to what our experimental subjects had. This facilitated realignment of their body's clock."
The take-home message for occupational health professionals? "Be aware of the tools at your disposal for counteracting problems associated with night shift work," says Smith.
1. Smith MR, Eastman CL. Night shift performance is improved by a compromise circadian phase position. Sleep 2008; 31:1,639-1,645.
For more information on improving productivity of night shift workers, contact:
Mark Smith, PhD, Post-Doctoral Fellow, Rush University Biological Rhythms Research Lab, Chicago. Phone: (312) 563-4783. Fax: (312) 563-4900. E-mail: Mark_Smith@rush.edu.