A very common danger to humans in cold temperatures is hypothermia and nowhere more so than in Antarctica. The potentially fatal condition sets in when the body cannot generate enough heat to regain the warmth it has lost.
Our bodies runs at a comfortable 37°C. Hypothermia sets when core body temperature drops below 35.5°C. Signs include sleepiness, confused speech, and clumsiness.
The body fights the lower body temperature by diverting blood away from hands and feet to the core. This causes blood vessels in the extremities to constrict, resulting in loss of physical coordination. Eventually vital bodily functions begin to slow down to conserve energy and heat, including the heart, which can go into cardiac arrest.
The simple answer to avoiding hypothermia is to keep warm. How does the crew at Antarctica manage this?
By dressing smart. When preparing to go out into Antarctic temperatures, crew must keep a few different factors in mind. Temperatures fluctuate depending on where they are located along the peninsula as well as season.
Concordia is situated on Dome C, a summit with elevation of 3233 metres and some 1670 km distance from the geographic South Pole. It is one of the coldest areas on Earth. Summer temperatures range from −25°C to as low as below −80 °C. The annual average air temperature is −54.5 °C, with low humidity and little or no precipitation throughout the year. It is hardly a wonder why it is known as the world’s largest frozen desert.
Crew headed to Concordia are given about 17 kg of Artic gear. The incoming ESA-sponsored medical doctor for the 2018-2019 season, Dr. Nadja Albersten of Denmark, recently blogged about her “goodie bag” which includes:
1 down jacket and down pant,
1 thin jumpsuit (which is actually quite fat)
2 sets of ski underwear,
8 pairs of gloves / mitts in different thicknesses,
5 pairs of inner gloves,
1 pair of polar boots + extra inner boots and extra soles,
1 pair of slippers in grandfather design,
2 pairs of cotton trousers,
1 fleece jacket,
1 wool sweater,
5 pairs of socks
goggles and sunglasses,
lip balm and sun screen
With these essentials, crew members can layer up with insulating inner clothing and water- and wind-proof outer layers, bearing their intended level of activity in mind. Keeping dry is crucial to staying warm, so wearing just enough to keep warm is a good baseline. Extra sweaters, hats, gloves, and headgear are good to have on hand, to change in case they get wet or to add layers as needed.
The outgoing ESA medical doctor Carmen Possnig demonstrates layering up in this gif:
Of course, hypothermia remains a real threat, as does frostbite, trench foot, and even sunburn. But the crew are properly geared and trained, and always look out for one another to catch any onset signs of these cold weather afflictions.