Effectiveness of a red-visor cap for preventing light-induced melatonin suppression during simulated night work

Shigekazu Higuchi, Tomomi Fukuda, Tomoaki Kozaki, Masaya Takahashi, Nobuhiko Miura

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Bright light at night improves the alertness of night workers. Melatonin suppression induced by light at night is, however, reported to be a possible risk factor for breast cancer. Short-wavelength light has a strong impact on melatonin suppression. A red-visor cap can cut the short-wavelength light from the upper visual field selectively with no adverse effects on visibility. The purpose of this study was to investigate the effects of a red-visor cap on light-induced melatonin suppression, performance, and sleepiness at night. Eleven healthy young male adults (mean age: 21.2±0.9yr) volunteered to participate in this study. On the first day, the subjects spent time in dim light (<15 lx) from 20:00 to 03:00 to measure baseline data of nocturnal salivary melatonin concentration. On the second day, the subjects were exposed to light for four hours from 23:00 to 03:00 with a nonvisor cap (500 lx), red-visor cap (approx. 160 lx) and blue-visor cap (approx. 160 lx). Subjective sleepiness and performance of a psychomotor vigilance task (PVT) were also measured on the second day. Compared to salivary melatonin concentration under dim light, the decrease in melatonin concentration was significant in a nonvisor cap condition but was not significant in a red-visor cap condition. The percentages of melatonin suppression in the nonvisor cap and red-visor cap conditions at 4hours after exposure to light were 52.6±22.4% and 7.7±3.3%, respectively. The red-visor cap had no adverse effect on performance of the PVT, brightness and visual comfort, though it tended to increase subjective sleepiness. These results suggest that a red-visor cap is effective in preventing melatonin suppression with no adverse effects on vigilance performance, brightness and visibility.

Original languageEnglish
Pages (from-to)251-258
Number of pages8
JournalJournal of physiological anthropology
Volume30
Issue number6
DOIs
Publication statusPublished - Dec 1 2011

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nightwork
Melatonin
suppression
Light
performance
Psychomotor Performance
Visibility
Luminance
cancer
Wavelength
worker
Visual Fields
Young Adult

All Science Journal Classification (ASJC) codes

  • Human Factors and Ergonomics
  • Physiology
  • Orthopedics and Sports Medicine
  • Anthropology
  • Public Health, Environmental and Occupational Health
  • Physiology (medical)

Cite this

Effectiveness of a red-visor cap for preventing light-induced melatonin suppression during simulated night work. / Higuchi, Shigekazu; Fukuda, Tomomi; Kozaki, Tomoaki; Takahashi, Masaya; Miura, Nobuhiko.

In: Journal of physiological anthropology, Vol. 30, No. 6, 01.12.2011, p. 251-258.

Research output: Contribution to journalArticle

Higuchi, Shigekazu ; Fukuda, Tomomi ; Kozaki, Tomoaki ; Takahashi, Masaya ; Miura, Nobuhiko. / Effectiveness of a red-visor cap for preventing light-induced melatonin suppression during simulated night work. In: Journal of physiological anthropology. 2011 ; Vol. 30, No. 6. pp. 251-258.
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