Seasonal changes in human sleep-wake rhythm in Antarctica and Japan

Akira Usui, Ichio Obinata, Yoshikazu Ishizuka, Tamio Okado, Hitoshi Fukuzawa, Shigenobu Kanba

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


The subjects were eight men of the Japanese Antarctic Research Expedition (average age 35.8 years), and 10 healthy people living around Kofu, Japan (28.9 years). They completed a sleep log for 12 to 18 months, and the sleep-wake state was scored in 10-min epochs. Q24 values calculated by χ2 periodgram were low in the Antarctic midwinter. This means that there was difficulty in synchronizing to a 24-h period in the Antarctic midwinter. In Antarctica, sleep onset and offset times were delayed mostly in the midwinter. In Japan, sleep offset time was delayed mostly around the winter solstice.

Original languageEnglish
Pages (from-to)361-362
Number of pages2
JournalPsychiatry and clinical neurosciences
Issue number3
Publication statusPublished - Jun 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Neurology
  • Clinical Neurology
  • Psychiatry and Mental health


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