Sleep impairment and altered pattern of circadian biomarkers during a long-term Antarctic summer camp.

Antarctic expeditions include isolation and exposure to cold and extreme photoperiods (with continuous natural light during summer) that may influence psychophysiological responses modulated by luminosity and sleep. We assessed changes in night sleep patterns by actigraphy, salivary biomarkers, and perceptual variables in seven participants in the following time points along a 50-day camping expedition in Antarctica (Nelson Island): Pre-Field (i.e., on the ship before camp), Field-1, Field-2, Field-3, Field-4 (from 1st to 10th, 11th to 20th, 21st to 35th and 36th to 50th days in camp, respectively), and Post-Field (on the ship after camp). We also characterized mood states, daytime sleepiness, and sleep quality by questionnaires. Staying in an Antarctic camp reduced sleep efficiency (5.2%) and increased the number of awakenings and wakefulness after sleep onset (51.8% and 67.1%, respectively). Furthermore, transient increases in time in bed (16.5%) and sleep onset latency (4.8 ± 4.0 min, from Pre- to Field-3) was observed. These changes were accompanied by an altered pattern of the emerging circadian marker ß-Arrestin-1 and a trend to reduce nocturnal melatonin [57.1%; P = 0.066, with large effect size (ES) from Pre-Field to Field-2 (ES = 1.2) and Field-3 (ES = 1.2)]. All changes returned to Pre-Field values during the Post-Field. The volunteers reported sleep-related physical complaints (feeling of cold and pain, discomfort to breathe, and cough or loud snoring), excessive daytime sleepiness, and reduced vigor during the camp. Thus, a 50-day camp alters neuroendocrine regulation and induces physical discomfort, which may explain the impaired sleep pattern and the consequent daytime sleepiness and mood changes.

Exploring the Predeployment Phase of an Antarctic Expedition and the Brazilian Pre-Antarctic Training.

In Antarctica, human access and presence are complex and require detailed planning and preparation in advance. The personnel of National Antarctic Programs (NAPs, i.e., scientists and support personnel, including military, civilians, and mountaineers) stay in different isolation, confinement, and extreme (ICE) environments such as ships, research stations, and scientific summer camps. Antarctica imposes harsh conditions that influence physiological and psychological responses impacting health, mood, and physical and cognitive performances. In this context, we argue why people should prepare in advance for staying in Antarctica and what to expect in ICE environments. We also spotlighted recommendations shared by different NAPs participant guides, including predeployment training. Next, we present a case study of the Brazilian Pre-Antarctic Training (PAT), a theoretical-practical training that provides technical and logistical information and assesses the adaptability and physical capacity of researchers and military personnel to perform fundamental activities in a polar environment. We evaluated and compared the individual's mood at the beginning and the end of the PAT week and observed group-specific mood changes depending on the sex, functions, and the facilities that participants accessed. Finally, we proposed that conducting training before staying in Antarctica, besides promoting conditions to better plan the voyage and knowledge of the region, can contribute to dealing with the possible mood swings during expeditions and even promote positive affect. Therefore, the psychophysiological effects of PAT are topics for further investigations.