Sleep in Isolated, Confined, and Extreme (ICE): A Review on the Different Factors Affecting Human Sleep in ICE

Abstract

The recently renewed focus on the human exploration of outer space has boosted the interest toward a variety of questions regarding health of astronauts and cosmonauts. Among the others, sleep has traditionally been considered a central issue. To extend the research chances, human sleep alterations have been investigated in several analog environments, called ICEs (Isolated, Confined, and Extreme). ICEs share different features with the spaceflight itself and have been implemented in natural facilities and artificial simulations. The current paper presents a systematic review of research findings on sleep disturbances in ICEs. We looked for evidence from studies run in polar settings (mostly Antarctica) during space missions, Head-Down Bed-Rest protocols, simulations, and in a few ICE-resembling settings such as caves and submarines. Even though research has shown that sleep can be widely affected in ICEs, mostly evidencing general and non-specific changes in REM and SWS sleep, results show a very blurred picture, often with contradictory findings. The variable coexistence of the many factors characterizing the ICE environments (such as isolation and confinement, microgravity, circadian disentrainment, hypoxia, noise levels, and radiations) does not provide a clear indication of what role is played by each factor per se or in association one with each other in determining the pattern observed, and how. Most importantly, a number of methodological limitations contribute immensely to the unclear pattern of results reported in the literature. Among them, small sample sizes, small effect sizes, and large variability among experimental conditions, protocols, and measurements make it difficult to draw hints about whether sleep alterations in ICEs do exist due to the specific environmental characteristics, and which of them plays a major role. More systematic and cross-settings research is needed to address the mechanisms underlying the sleep alterations in ICE environments and possibly develop appropriate countermeasures to be used during long-term space missions.

The impact of the COVID-19 lockdown on human psychology and physical activity; a space analogue research perspective

“…ICE environments are very complex environments in which various types of stressors constantly and simultaneously affect human functioning (i.e., physical and mental performance) and psychophysiology. Knowledge about the relative weight of each factor that makes up an ICE environment, as well as about the impact of an ICE environment on human functioning and psychophysiology is of paramount importance to develop effective countermeasures and to ensure mission success (Zivi et al, 2020). For example, factors that are known to play a role in the effect of an ICE environment on human functioning during space missions include long-term microgravity, constant noise, radiation and prolonged isolation (Zivi et al, 2020).…”

“…Knowledge about the relative weight of each factor that makes up an ICE environment, as well as about the impact of an ICE environment on human functioning and psychophysiology is of paramount importance to develop effective countermeasures and to ensure mission success (Zivi et al, 2020). For example, factors that are known to play a role in the effect of an ICE environment on human functioning during space missions include long-term microgravity, constant noise, radiation and prolonged isolation (Zivi et al, 2020). Currently, it is well known that interindividual differences exist in how quickly one adapts to ICE conditions.…”

Monitoring the Impact of Spaceflight on the Human Brain

“…Docking simulation tasks indicate an increase in global theta EEG oscillations while in space as compared to the same task on Earth. This was also associated with slower reaction times during the task, which has important implications for astronauts [33]. Life 2022, 12, x FOR PEER REVIEW 5 of 18…”

To infinity and beyond: Strategies for fabricating medicines in outer space

“… Spaceflight hazard Clinical conditions Management strategies Possible medications References Space radiation Degenerative diseases (e.g. cardiovascular diseases and cataracts) Radiation shielding, radiation & health monitoring Antioxidants ⁎ ( Fang et al, 2002 ; Gómez et al, 2021 ) Cancer Radiation shielding, radiation & health monitoring Antioxidants ⁎ ( Gómez et al, 2021 ; Montesinos et al, 2021 ) Changes in the central nervous system Radiation shielding, radiation & health monitoring Antioxidants ⁎ ( Cucinotta et al, 2014 ; Gómez et al, 2021 ) Isolation and confinement Behavioural changes Gardening and journaling Antipsychotics (aripiprazole and ziprasidone), anxiolytics (diazepam and lorazepam) ( Friedman and Bui, 2017 ; Odeh and Guy, 2017 ) Sleep problems Light technologies, actigraphy Hypnotic drugs (zolpidem, zaleplon), melatonin ( Friedman and Bui, 2017 ; Zivi et al, 2020 ) Fatigue 10-min self-test of vigilance and attention ( Basner et al, 2011 ) Decline in mood Journaling, virtual reality sessions Antidepressants (sertraline and venlafaxine) ( Friedman and Bui, 2017 ; Lyons et al, 2020 ) Gravity fields Muscle atrophy Aerobic and resistive exercise, software-generated workout partners ( Feltz et al, 2016 ; Gao and Chilibeck, 2020 ) Bone loss Aerobic and resistive exercise, software-generated workout partners Bisphosphonate alendronate, supplements of calcium, vitamin D an...…”