Local sleep-like events during wakefulness and their relationship to decreased alertness in astronauts on ISS

• DOI: 10.1038/s41526-019-0069-0
• Publication Date: 2019-05-02T10:04:37Z
• Authors: Gaetan Petit; Ana Maria Cebolla; Sara Fattinger; Mathieu Petieau; Leopold Summerer; Guy Cheron; Reto Huber
• Keywords: 0301 basic medicine; 1101 Agricultural and Biological Sciences (miscellaneous); 610 Medicine & health; 2701 Medicine (miscellaneous); Généralités; 2501 Materials Science (miscellaneous); 1301 Biochemistry, Genetics and Molecular Biology (miscellaneous); Article; 03 medical and health sciences; 1912 Space and Planetary Science; 10036 Medical Clinic; 13. Climate action; 10058 Child and Adolescent Psychiatry; 3101 Physics and Astronomy (miscellaneous)

AbstractAdequate sleep quantity and quality is required to maintain vigilance, cognitive and learning processes. A decrease of sleep quantity preflight and on the International Space Station (ISS) has been reported. Recent counter-measures have been implemented to better regulate sleep opportunities on ISS. In our study, astronauts were allocated enough time for sleep the night before the recordings. However, for proper sleep recovery, the quality of sleep is also critical. Unfortunately, data on sleep quality have yet to be acquired from the ISS. Here, we investigate sleep pressure markers during wakefulness in five astronauts throughout their 6-month space mission by the mean of electroencephalographic recordings. We show a global increase of theta oscillations (5–7 Hz) on the ISS compared to on Earth before the mission. We also show that local sleep-like events, another marker of sleep pressure, are more global in space (p < 0.001). By analysing the performances of the astronauts during a docking simulation, we found that local sleep-like events are more global when reaction times are slower (R2 = 0.03, p = 0.006) and there is an increase of reaction times above 244 ms after 2 months in space (p = 0.012). Our analyses provide first evidence for increased sleep pressure in space and raise awareness on possible impacts on visuomotor performances in space.