Open AccessEffect of bright light on tolerance to night work.
Author(s) -
Giovanni Costa,
Giovanna Ghirlanda,
D S Minors,
Jim Waterhouse
Publication year - 1993
Publication title -
scandinavian journal of work, environment and health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.621
H-Index - 103
eISSN - 1795-990X
pISSN - 0355-3140
DOI - 10.5271/sjweh.1453
Subject(s) - melatonin , audiology , shift work , sleep (system call) , medicine , circadian rhythm , nocturnal , zoology , physiology , endocrinology , biology , psychiatry , computer science , operating system
Fifteen young (mean age 23.4 years) female nurses engaged in a resuscitation unit and working on a fast rotating shift schedule comprising two consecutive night shifts were exposed to short periods (4 x 20 min) of bright light (2350 lx) during their night duty to test a possible positive effect on their tolerance to night work. Two nights with normal lighting (20-380 lx) and two nights with bright light were compared. The following positive effects of bright light upon psychophysical conditions and performance efficiency were noted: in particular, signs of better physical fitness; less tiredness and sleepiness; a more balanced sleep pattern; and higher performance efficiency (letter cancellation test). This result could not be attributed to shifts of the internal clock although the exact cause remains to be determined. In fact, hormonal excretion and body temperature did not show any effect from bright light. In addition melatonin excretion was not suppressed appreciably by the bright light used.