Abstract
To understand the factors that alter sleep quality in space, we studied the effect of spaceflight on sleep-disordered breathing. We analyzed 77 8-h, full polysomnographic recordings (PSGs) from five healthy subjects before spaceflight, on four occasions per subject during either a 16- or 9-d space shuttle mission and shortly after return to earth. Microgravity was associated with a 55% reduction in the apnea-hypopnea index (AHI), which decreased from a preflight value of 8.3 ± 1.6 to 3.4 ± 0.8 events/h inflight. This reduction in AHI was accompanied by a virtual elimination of snoring, which fell from 16.5 ± 3.0% of total sleep time preflight to 0.7 ± 0.5% inflight. Electroencephalogram (EEG) arousals also decreased in microgravity (by 19%), and this decrease was almost entirely a consequence of the reduction in respiratory-related arousals, which fell from 5.5 ± 1.2 arousals/h preflight to 1.8 ± 0.6 inflight. Postflight there was a return to near or slightly above preflight levels in these variables. We conclude that sleep quality during spaceflight is not degraded by sleep-disordered breathing. This is the first direct demonstration that gravity plays a dominant role in the generation of apneas, hypopneas, and snoring in healthy subjects.
Original language | English (US) |
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Pages (from-to) | 478-485 |
Number of pages | 8 |
Journal | American journal of respiratory and critical care medicine |
Volume | 164 |
Issue number | 3 |
DOIs | |
State | Published - Aug 1 2001 |
Externally published | Yes |
Keywords
- Airway collapse
- Arousals
- Gravitational effect
- Obstructive sleep apnea
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Critical Care and Intensive Care Medicine