Changes in sleep quality of athletes under normobaric hypoxia equivalent to 2,000-m altitude: A polysomnographic study

Masako Hoshikawa*, Sunao Uchida, Takayuki Sugo, Yasuko Kumai, Yoshiteru Hanai, Takashi Kawahara

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    37 Citations (Scopus)


    This study evaluated the sleep quality of athletes in normobaric hypoxia at a simulated altitude of 2,000 m. Eight male athletes slept in normoxic condition (NC) and hypoxic conditions equivalent to those at 2,000-m altitude (HC). Polysomnographic recordings of sleep included the electroencephalogram (EEG), electrooculogram, chin surface electromyogram, and electrocardiogram. Thoracic and abdominal motion, nasal and oral airflow, and arterial blood oxygen saturation (SaO2) were also recorded. Standard visual sleep stage scoring and fast Fourier transformation analyses of the EEG were performed on 30-s epochs. Subjective sleepiness and urinary catecholamines were also monitored. Mean SaO2 decreased and respiratory disturbances increased with HC. The increase in respiratory disturbances was significant, but the increase was small and subclinical. The duration of slow-wave sleep (stage 3 and 4) and total delta power (<3 Hz) of the all-night non-rapid eye movement sleep EEG decreased for HC compared with NC. Subjective sleepiness and amounts of urinary catecholamines did not differ between the conditions. These results indicate that acute exposure to normobaric hypoxia equivalent to that at 2,000-m altitude decreased slow-wave sleep in athletes, but it did not change subjective sleepiness or amounts of urinary catecholamines.

    Original languageEnglish
    Pages (from-to)2005-2011
    Number of pages7
    JournalJournal of Applied Physiology
    Issue number6
    Publication statusPublished - 2007 Dec


    • Normobaric hypoxia
    • Polysomnography
    • Respiratory disturbances
    • Slow-wave sleep

    ASJC Scopus subject areas

    • Physiology
    • Endocrinology
    • Orthopedics and Sports Medicine
    • Physical Therapy, Sports Therapy and Rehabilitation


    Dive into the research topics of 'Changes in sleep quality of athletes under normobaric hypoxia equivalent to 2,000-m altitude: A polysomnographic study'. Together they form a unique fingerprint.

    Cite this