Key result
Prolonged Antarctic isolation and polar night linked to altered sleep-wake parasympathetic HRV.
Why the study?
The extent to which human physiology, particularly the sleep-wake cycle and circadian rhythms, adapts to isolated, confined, and extreme environments remains unclear.
Does prolonged isolation and the polar night affect autonomic nervous system activity in Antarctic crewmembers?
Observational (n=13)
No
Does prolonged isolation and the polar night affect autonomic nervous system activity in Antarctic crewmembers?
p-value: p=<0.001
Prolonged isolation and polar night in extreme environments significantly alter cardiac autonomic modulation, providing insights for developing countermeasures against stress-related health issues.
May guide countermeasures for autonomic stress in isolated settings; leaves open generalizability and clinical relevance beyond Antarctic cohorts.
Isolated, confined and extreme environments like Antarctic overwinterings present significant challenges to human psychophysiological adaptation. While previous evidence suggests that such conditions affect autonomic response, the extent to which human physiology adapts, in particular, the sleep-wake cycle and circadian rhythms, remains unclear. To assess the impact of prolonged isolation and the polar night on autonomic nervous system activity, we conducted an observational and longitudinal study at Belgrano II Argentine Antarctic station over a year-long campaign. Heart rate variability, a measure of cardiac autonomic modulation, was computed in 13 crewmembers over 24-hour periods every two months. Analysis revealed a decrease in parasympathetic regulation during wakefulness and an increase during sleep, in association with the increasing duration of isolation. At the same time, parasympathetic activity during sleep decreased during the polar night, suggesting a distinct seasonal effect. These findings offer novel insights into how isolation and the polar night influence autonomic regulation. Understanding these physiological adaptations is crucial for developing effective countermeasures to mitigate stress-related health issues in extreme environments.
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Tortello et al. (2026) conducted an observational in Healthy (Antarctic overwintering) (n=13). Antarctic overwintering (isolation and polar night) vs. Time progression was evaluated on Changes in sleep-wake heart rate variability (HRV) indices over time (p=<0.001). Prolonged Antarctic isolation decreased parasympathetic regulation during wakefulness and increased it during sleep, while the polar night decreased parasympathetic activity during sleep.
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