The aim for this study is to find out whether disturbances in the sleep-wake cycle created by working during the night could be prevented by exposure to bright light during the night and darkness during the day.
For this study 8 young men (aged 22-29) who were not used to shift work were asked to arrive at 23:45 for 6 nights. One group of participants worked in ordinary indoor light at 150 lux. The other group were exposed to extreme bright light at 700 lux. After their shift they were instructed to go home and sleep in complete darkness from 9am - 5pm. The core body temp of the men was recorded over the research for both groups. Cognitive tests and self-report mood and alertness questionnaires were also taken.
The results of this experiment were:. Temperatrues of group with ordinary light fell during the night which replicated what would happen during sleep. . The ordinary group had not adapted. They experienced the sleep part of circadian rhythm at night even when working.. After 4 days the temperature of the group exposed to bright light fell at midday. . The bright light group had successfully adapted their circadian rhythm to the night-time work schedule. Bright light group showed improvements on all tests including mood, alertness and concentration.