"The Antarctic environment induces adaptive metabolic and neuroendocrine changes associated with survival, as well as increased risks to physical and mental health. Circadian disruption has been observed in Antarctic expeditioners.
The main consequences appear in quality of sleep, which can affect physical and cognitive performance. Physiological adaptation to cold is mediated by the norepinephrine and thyroid hormones. The observed changes in the hypothalamic-pituitary-thyroid (HPT) axis of expeditioners varied according to temperature, photoperiod, time spent in the cold environment and stress level.
The decrease in T3 levels has frequently been associated with mood swings. Psychological and physical stressors cause disturbances in the hypothalamic-pituitary-adrenal (HPA) axis, with consequent maintenance of high cortisol levels, leading to memory impairment, immunosuppression, and cardiometabolic and reproductive disorders.
Preventive measures, such as provision of adequate food, well-established eating times, physical activity and even the use of phototherapy, can all help maintain the circadian rhythm. In addition, the use of high-tech clothing and room temperature control in research stations provide greater protection against the effects of intense cold.
However, psychological stress requires a more individualized approach based on the crew's sociocultural characteristics, but it can be mitigated by mental healthcare and training in coping strategies." The researchers said this in the study Human adaptative behavior to Antarctic conditions: A review of physiological aspects, published on the WIREs mechanisms of disease.
In Antarctica there are the two largest ice shelves in the world, that of Ross and that of Filchner-Ronne. The continent is surrounded by a large frozen area, the pack ice, in which one of the most interesting ecosystems on the planet develops and which is the source of food for cetaceans, penguins, fish, seals and many birds.
There are over 70 lakes in Antarctica, located thousands of meters below the frozen blanket. The largest of these sub-glacial lakes is Lake Vostok, discovered by the Russian geographer Andrey Kapitsa during a series of Soviet scientific expeditions that took place between 1959 and 1964 near the Russian Vostok station.
The lake is believed to have been ice sealed between 500,000 and 1 million years ago. There is evidence from cores carried out about 400 m above the lake's water surface that its waters may contain life forms (microbes).
This has been brought to support the theories on the possibility of life forms on Europa, one of Jupiter's moons, as the frozen surface of the lake has many features in common with the surface of the satellite.