Sleep and Circadian Rhythms in Space

Abstract

This paper presents a detailed critical review of the knowledge accumulated in the last three decades concerning research on sleep, work-rest schedules, and circadian rhythms in space. The focus of the paper is preceded by a brief review of the basic principles of the human circadian system and the physiology of the sleep-wake cycle, relevant to understanding the problem of astronaut work-rest scheduling. Much of what is known is based on anecdotal reports, mission log books, and debriefing of astronauts after flights. The broad literature reviewed, which includes studies from American and Soviet space missions, as well as some studies conducted under simulated weightlessness, offers just a handful of objective studies on the physiology of sleep and circadian rhythms in space. Nevertheless, the data are remarkably consistent, and indicate that sleep can be of reasonably good quality in space. The risk of sleep loss and associated performance degradation appears to be a manageable one. However, one clear conclusion arises from this review: whatever the type of mission of flight plan, its success will depend on whether the principles of circadian and sleep-wake regulation have been taken into account during the planning phase of work-rest schedules. That is, satisfactory sleep and alertness is more likely to occur if crews maintain a reasonable (i.e., constant) relation with their normal terrestrial rhythm. This is not as easy a task as it may appear; indeed, unexpected, high-intensity operational demands have been the major cause of acute problems of sleep loss and performance degradation in space. Moreover, the growing complexity of space missions indicate that emergencies will never disappear. Therefore, one of the most important research challenges for future space missions is the development of strategies that could permit astronauts to function closest to maximal efficiency during intensive and prolonged work. Countermeasures for optimizing astronaut performance, as well as other factors affecting sleep and performance in space, are reviewed and discussed in detail in this paper.

During the Long Way to Mars: Effects of 520 Days of Confinement (Mars500) on the Assessment of Affective Stimuli and Stage Alteration in Mood and Plasma Hormone Levels

“…Aside from actual spaceflights, a number of similar expeditions under isolated and confined environments (ICEs) have been performed to study human mental issues, including Antarctic exploration [5], [6], [7], submarine mission [8], ground-based spaceflight simulation, and others [9], [10], [11], [12]. Previous studies have found evidence of decrement in the variables of cognitive performance [13], [14], [15], team cohesion [1], [3], [4], [16], locomotor function [10], [11], [17], circadian rhythm and sleep [2], [3], [18], [19], etc. Moreover, the strong association between the function of the neuroendocrine system and emotion processing and stress coping has also been observed [20], [21], [22], [23].…”

Urinary Metabolic Profiling of ‘MARS-500 Project’ with Nuclear Magnetic Resonance Spectroscopy

“…Whereas, a sustaining decrease in the last three periods might be caused by bad physiological problems. Changing in circadian rhythms under an isolated environment has also been reported in many publications [28][29][30]. It has been shown that sleep time had decreased for people when they were pooled into an isolated and predefined space.…”

Radiated susceptibility of breath monitoring system based on UWB pulses in spacecraft modules

“…In particular in figure 6 the comparison between the received signal in the first 10ns between the simulation with the dielectric phantom ( r =40;σ=1;) and the PEC phantom. The antenna is placed in front of the phantom and the signal has a bandwidth of [3][4][5] GHz.…”

“…In fact, rest and sleep have been consistently reported as being of poor quality in microgravity, both by American astronauts and Russian cosmonauts [3,4] but up to now only few studies have addressed the combined action of microgravity and rest on respiration and chest wall mechanics.…”