Human psychophysiology in Antarctica

Psychology in Antarctica

The first thing that happens on reaching Antarctica is the devastation of sleep. Antarctic arrivals of the expedition teams are conducted in austral summer (November–February); on reaching the continent, illumination with constant bright sunlight disrupts the biological clock. The individual also faces constant darkness during the austral winters. This change in photoperiod starts a constellation of psychological problems in an individual.

Polar station settings are stressful in terms of boredom, limited supplies and equipment. Confinement in the Antarctic is not because of the small living space but due to the inability to leave the station and the group.^[1] There is a complete physical separation from family and friends for months. Harrison and Connors stated that, “Typically, mood and morale reach nadir somewhere between the one-half and two-thirds mark of the mission,” popularly known as the third-quarter phenomenon. A medical doctor in the Belgian expedition (1897–9) said that, “The curtain of blackness which has fallen over the outer world of icy desolation has also descended upon the inner world of souls…. men are sitting about sad and dejected, lost in dreams of melancholy…. all efforts to infuse bright hopes fail”(Cook, 1900/1980:282). On Scott’s second expedition, Debenham quoted it as, “the scenery has lost much of its beauty to us, the auroras are cheap and the cold rather colder.”^[1]

There are three broad stages of common human reaction in an ICE set. The first stage is heightened anxiety when the individual arrives in Antarctica or any ICE. The second stage is the ensuing depression and settling down to the routine forced. Near completion of the expedition, the third stage that can be detrimental for the individual and the team is emotional outbursts, aggressiveness, and rowdy behavior.^[2] Sometimes, adverse human reactions and consequences have been overestimated in ICE environments.^[3] Participants also encounter favorable experiences and may positively transform their personality and do better in their professional and personal lives after returning to civilization. This change in one’s orientation is recognized as “salutogenesis,”^[4] that is a positive attitude towards life and increased self-confidence. Salutogenic behavior may arise due to accomplishment after adjusting to a new and unique environment. It can result from a sense of heroism, bravery, self-sacrifice, and conquest.^[5,6]

Social erosion has been frequently reported in polar expeditions. One of the reasons is the lack of will for clear communication among the team members. The team leaders’ efficiency and sensitivity to the needs and welfare of the team members also play a pivotal role.^[7-9] The team leaders’ governance practices affect team members’ communication, output, and morale. The crew under strict leaders has less open communication and work output than the leaders, which fosters a relaxed and harmonious work environment.^[10] Differences in occupations among the team members can cause friction and conflicts because Antarctic teams are composed of scientific and other coordinators. The scientists have a specific research task, and they may not quickly “mold” to the station duties as good as the coordination personnel and contribute to the “role stress.” An Antarctic team consisting of team members with average rates of extraversion-introversion and low neuroticism and psychoticism does well.^[11]

Team members overwintering in Antarctica also come across “intellectual inertia” in which decreased intellectual ability was noticed to any added tasks or projects given during near completion of the expedition. It is characteristic of diminished memory and concentration. The phenomenon was best described because of a lack of sensory inputs and relatively “sameness” encountered by the team members overwintering.^[12]

The modern Antarctic stations are equipped with the internet; this feature has positive and negative effects on psychological well-being. Personnel can stay connected with their family and friends, thus reducing social isolation. However, at the same time, if any problem occurs in their social circle, then they feel helpless.^[5]

The main challenge faced by the expedition team during austral winter by early explorers is described [Figure 2] as the qualities of an explorer as “optimistic; patient physically fit; the man with a cheerful disposition and ready laugh is a bright sun to his companions and a great help to the leader of the expedition.”^[1] Shackleton’s statement seems factual following an excerpt from the diary of his expedition team member Frank Wild: “several times I fell into crevasses, as everyone did. While hanging in the harness I prayed that the rope would break so that I would have a nice long rest.”^[13]

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Figure 2:

Working in Antarctica can bring favorable behavioral modifications like a sense of achievement and higher self-confidence later in life. It is also associated with a constellation of psychological issues.

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Physiology in Antarctica

Physical stress is caused due to working in rough terrain often covered with snow. It tremendously increases the load and maybe tolerated by the individuals having lower baseline change in maximal oxygen consumption (VO_2MAX) than those with already higher VO_2MAX.^[14] Injuries are the most common morbidity among Antarctic expedition teams.^[15] Working in icy conditions can bring musculoskeletal disorders and increased chances of slips, trips, falls, and cognitive impairments, leading to a decrease in the chances of survival.

Task performance under 10°C for durations higher than 2 h can adversely affect physiological well-being.^[16]

Disturbance in the normal levels of the hypothalamic-pituitary-thyroid axis has been reported in the polar sojourners.^[17,18] A decrease in total and free triiodothyronine thyroid hormone with increased thyroid-stimulating hormone. This phenomenon is known as Polar T₃ syndrome. The expected level of thyroid hormones is critical for keeping metabolism, cold acclimatization, and mood. The abnormal fluctuations of the thyroid hormones seriously affect the well-being of an individual in circumpolar regions. The clinical significance of the syndrome can be determined by thyroxine supplementation, and yoga has been suggested to manage polar T₃ syndrome.^[9,19]

Cortisol, a glucocorticoid and a stress biomarker, has increased during an Antarctic expedition. Due to the unregulated hypothalamus-pituitary-adrenal axis and sustained elevated glucocorticoid levels. Prolonged exposure to glucocorticoids can cause atrophy of the hippocampus neurons and poor memory.^[20] If a strict routine is forced on the team-mates, then a disturbance in diurnal rhythms of cortisol and some symptoms of over-winter syndrome can be prevented.^[21] Higher levels of plasma noradrenaline were found with higher latitude Antarctic residence.^[22]

Autonomic balance and menstrual cycle

Studies in Antarctica over WOT reported sympathetic dominance among WOT.^[23] Sympathetic dominance could cause hypertension, hypercortisolism, high breathing and heart rate, and poor sleep. Sympathetic overdrive can have adverse health effects.

A study reported suppression in luteinizing hormone reactivity before and during an Antarctic traverse, whereas follicle-stimulating hormone did not change during and after the expedition.^[24]

Circadian rhythm and melatonin

In normal geographical conditions, the pineal secretion of melatonin occurs from late evening to early morning. Apart from external cues, the circadian rhythm depends on work habits, meal times, and social interactions. The periodicity of circadian rhythm is ~24h typically. However, it runs freely in polar and space environments with decreased stability.^[25] Antarctica is a natural laboratory to study circadian rhythm omitting the 12h day-night cues. Pattyn et al., and Arendt reviewed the topic independently and concluded a delay in sleep onset and awakening and sleep fragmentation in Antarctica, including an inconclusive trend of melatonin secretion.^[26,27]

Hypoxia along with extreme cold!

Antarctica has the highest average altitude among all the continents.^[28] The barometric pressure in polar conditions is not equivalent to lower latitudes’ atmospheric pressure at the same altitude. The earth’s spin and cold air caused by the Ferrel cell wind belt alter the barometric pressure to be lower than what would be expected at the physical altitude of the South Pole altitude.^[29] Many Antarctic stations are located near the South Pole and are at a considerable altitude above sea level. Life is more stressful in such stations than at Antarctic seashores or near sea level.

AMS can rapidly occur in individuals traveling to altitudes over 2500m. It is generally assessed by a self-reported questionnaire called as Lake Louise questionnaire.^[30] The researchers found a significant reduction in blood pCO₂ and, consequently, an increase in blood pH at harmful base excess in the WOT and persistently increased hemoglobin concentration during the stay.^[31] Physical exertion due to extensive outdoor work in extreme cold increases AMS incidence significantly in the polar regions.^[29] Using oral contraceptive pills increases the risk of developing AMS.^[32] Researchers reported increased hematocrit, thrombocyte, lymphocyte, granulocytes, and monocytes while staying in the French-Italian Concordia station. They informed a significant decrease among lymphocyte subsets in the T-cell percentage, with a corresponding B-cell elevation.^[33] Periodic breathing, sleep fragmentation, and other sleep disturbances are common problems encountered in the Antarctic and other hypoxic environments.^[34] More than half of the Antarctic expeditioners who were uplifted to high altitude experienced symptoms of AMS.^[35]

Infections and immune response

The Antarctic environment is more sterile than other continents on earth. That is why there is diminished immune responsiveness in the wintering team. The lack of environmental and human propagated antigens and extreme cold and wind induce immune latency.^[36] Incidences of infections are low or absent in most expeditions. However, minor outbreaks, especially for upper respiratory infections, can occur during contact in the overlap period of the new expedition team with its predecessor team. For example, from 1956 to 2000 at Syowa station, the maximum number of common cold cases build-up in December, the month when fresh Antarctic recruits arrive.

Stress associated with wintering in Antarctica alters immune functions. Increased serum IgA and T_H1 cytokines have been reported among WOT compared to their baseline levels.^[37] Shirai et al., 2003, have reported a decrease in the serum levels of TNF-α, IL-6, and IL-1β and a significant increase in the natural killer T-cells during Antarctic isolation. They found that exposure to Antarctic winter induces T_H1-skewed immunity in human beings. An imbalance between T_H1 and T_H2 immunity which can lead to immune-associated diseases.^[38] No significant changes were found in secreted human leukocyte antigen-G in Antarctic expeditioners.^[39]

A study reported reduction in the proliferation of PBMC to phytohemagglutinin and depressed cutaneous delayed-type hypersensitivity reactions following 120 days of Antarctic isolation.^[40] Also, salivary IgA levels are low in March–May and the IgM levels low in Jan-April with peak levels in June-July.^[41]

Bone metabolic changes

Seasonal changes in Vitamin D synthesis and physical activity have been associated with bone metabolism. Age also influences it, so older adults are more susceptible to these changes than younger people. Vitamin D has two main types: Vitamin D₃ (cholecalciferol) and Vitamin D₂ (ergocalciferol). Cholecalciferol is synthesized utilizing 7-dehydrocholesterol of the cell membranes in the skin following exposure to ultraviolet B radiation, and ergocalciferol is formed by plants and obtained from the diet. Animals can also synthesize Vitamin D₃ and, therefore, be obtained in the diet. Vitamin D is metabolized in the liver to an inactive 25-hydroxyvitamin-D [25(OH)D]. Therefore, serum 25(OH) D reflects the amount of Vitamin D in the body. It is accepted that a 25(OH)D concentration <20 ng/ml reflects deficiency. The D₃ form is more effective in increasing 25(OH)D levels than the D₂ form. Vitamin D is a significant player in calcium homeostasis because it facilitates the body’s higher absorption of dietary calcium and phosphorus.^[42]

In austral winters, it was found that serum 25(OH)D₃ decreases due to significantly fewer hours of sunlight or no sunshine at all.^[43] However, the decrease was found within the clinical limits indicating utilization of reserve Vitamin D stored in the liver or intake from the diet, especially fish. Another study reported a reduction in serum 25(OH)D₃ in overwintering team members. Higher baseline Vitamin D serum concentrations have been suggested to overcome the deficiency.^[44] Iuliano-Burns et al., 2009, reported Vitamin D deficiency in 85% of the Australian expedition team after 6 months of winter-over in Antarctica. They informed a decrease in bone mass density in the members with serum 25(OH)D levels <50 nmol/L. They advised baseline assessments of serum 25(OH)D and supplementation for those with serum 25(OH)D levels <100 nmol/L. Decline in serum 25 (OH)D below <50 nmol/L was prevented through Vitamin D supplementation in the winter-over team.^[45] A decrease in the calcium content in human hair after 1 month’s stay in Antarctica has been associated with insufficient Vitamin D levels.^[46] High dietary sodium intake increases renal calcium excretion and can create a negative calcium balance, contributing to bone loss. Furthermore, heavy alcohol consumption intake contributes to decreased bone density.^[47]

Geomagnetism

A few researches have been conducted on the influence of geomagnetism on human physiology in polar geology. Geomagnetic force varies from 35 µT on the equator to 65 µT in circumpolar regions. The polar sojourners are bombarded with electromagnetic (EM) radiations, radiations from radionuclides such as thorium deposits in Antarctica,^[48] and high-intensity solar flux and eruptions throughout the austral summer. Interestingly, the magnetic part of the EM wave has been playing a dominant role in the onset of biological effects because of its ability to penetrate the human tissue. It has been proposed that the magnetic field increases the half-life of the free radicals in a biological fluid and interacts with the plasma membrane of cells to influence the ion transport across the membrane.^[49]

A common observation while living in a polar environment is the spark discharges from the skin. The ambient electric field settles on the body surface area and builds up continuously^[50] until discharged while touching another person or metallic objects.