Impact of exposure to dim light at night on sleep in female and comparison with male subjects

Chul Hyun Cho, Ho Kyoung Yoon, Seung Gul Kang, Leen Kim, Eun Il Lee, Heon Jeong Lee

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Objective Light pollution has become a social and health issue. We performed an experimental study to investigate impact of dim light at night (dLAN) on sleep in female subjects, with measurement of salivary melatonin. Methods The 25 female subjects (Group A: 12; Group B: 13 subjects) underwent a nocturnal polysomnography (NPSG) session with no light (Night 1) followed by an NPSG session randomly assigned to two conditions (Group A: 5; Group B: 10 lux) during a whole night of sleep (Night 2). Salivary melatonin was measured before and after sleep on each night. For further investigation, the female and male subjects of our previous study were collected (48 subjects), and differences according to gender were compared. Results dLAN during sleep was significantly associated with decreased total sleep time (TST; F=4.818, p=0.039), sleep efficiency (SE; F=5.072, p=0.034), and Stage R latency (F=4.664, p=0.041) for female subjects, and decreased TST (F=14.971, p<0.001) and SE (F=7.687, p=0.008), and increased wake time after sleep onset (F=6.322, p=0.015) and Stage R (F=5.031, p=0.03), with a night-group interaction (F=4.579, p=0.038) for total sample. However, no significant melatonin changes. There was no significant gender difference of the impact of dLAN on sleep, showing the negative changes in the amount and quality of sleep and the increase in rapid eye movement (REM) sleep in the both gender group under 10 lux condition. Conclusion We found a negative impact of exposure to dLAN on sleep in female as well as in merged subjects. REM sleep showed a pronounced increase under 10 lux than under 5 lux in merged subjects, suggesting the possibility of subtle influences of dLAN on REM sleep.

Original languageEnglish
Pages (from-to)520-530
Number of pages11
JournalPsychiatry Investigation
Issue number5
Publication statusPublished - 2018 May

Bibliographical note

Funding Information:
This study was supported by the Future Environmental R&D grant funded by the Korea Environmental Industry and Technology Institute (No. RE201206020) and by the Korea Health 21 R&D Project funded by the Ministry of Health & Welfare, Republic of Korea (HI14C3212).

Publisher Copyright:
© 2018 Korean Neuropsychiatric Association.


  • Dim light at night
  • Melatonin
  • Polysomnography
  • REM sleep
  • Sleep

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry


Dive into the research topics of 'Impact of exposure to dim light at night on sleep in female and comparison with male subjects'. Together they form a unique fingerprint.

Cite this