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

Abstract

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 (Sa(O(2))) 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 Sa(O(2)) 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.

Sleep evaluation by a newly developed PVDF sensor non-contact sheet: a comparison with standard polysomnography and wrist actigraphy

“…Thus, PSG has long been used to examine sleep quality changes across development and aging, after drug administration, and in pathological conditions and circumstances. [1][2][3][4] Since 1968, methods for PSG sleep evaluation have been standardized [5][6][7] making it possible to compare a generation of studies recorded in geographically and chronologically varied environments. Thus, for example, Kobayashi et al 8 were recently able to conduct a meta-analysis of 20 PSG studies to compare sleep in people with and without post-traumatic stress disorder (PTSD), finding PTSD patients had more stage 1 sleep, less slow-wave sleep, and greater rapid-eye-movement density.…”

Sleep quality under mild hypoxia in men with low hypoxic ventilatory response

“…However, in our previous study we demonstrated significant decreases in both visually scored slow-wave sleep and the underlying whole-night delta power of NREM sleep EEG at a simulated altitude of 2000 m (Hoshikawa et al, 2007). In that study, the subjects revealed lower mean blood oxygen saturation (SpO 2 ) than subjects in previous studies.…”

Sightings

“…Polysomnography in 8 male athletes acclimatized at sea level, when first sleeping at simulated 2000-m altitude, showed less slow-wave sleep (stages 3 and 4) and total delta power (Ͻ3 Hz) of the all-night NREM sleep, and significantly reduced Sp O 2 , but neither subjective subsequent sleepiness nor altered urinary catecholamines (Hoshikawa et al, 2007).…”