Sudden changes in temperature threaten serious consequences for a person, regardless of the time of year, but hypothermia poses a particularly serious health risk. Portal popsci.com speakwhy it is dangerous and the minimum temperature a person can withstand.
Mild hypothermia occurs when the body temperature drops to 35-32 degrees Celsius and symptoms are often difficult to notice. Patients may complain of hunger, irritability or confusion and their skin may become pale and dry.
Below 32 degrees Celsius, moderate hypothermia occurs. The patient may become lethargic and have a slow heart rate and breathing rate. At this temperature, the brain and its internal thermometer stop working correctly, which sometimes leads to strange behaviors, such as an irrational desire to undress. Finally, severe hypothermia occurs if the body temperature drops to 28 degrees Celsius. The human body begins to shut down: blood pressure and heart rate drop even lower.
With such symptoms, Anna Bagenholm's case is even more surprising. In 1999, a female radiologist fell during a skiing trip and was immersed in icy water for nearly an hour and a half. When rescuers found her, she was clinically dead, but doctors pulled her out of the water, put her on a ventilator and performed initial resuscitation. Then, once at the hospital, doctors connected Anna to a heart-lung machine, which warmed her body for three hours.
Bagenholm ended up on a ventilator for three months. Her blood stopped clotting, her nerves were damaged and her internal organs did not function properly. However, she miraculously survived – after 5 months, the girl returned to work and continued to walk.
Only one case of hypothermia exceeded the severity that Bagenholm suffered. In the winter of 2014, a Polish baby named Adam walked out of his grandmother's house in a village north of Krakow. At that time the outside temperature was -7 degrees Celsius.
Adam was found several hours later unconscious and motionless. His body was so frozen that rescuers couldn't even intubate Adam. Like Bagenholm, the baby was hospitalized and placed on a ventilator. Although his body temperature dropped to around 12 degrees, he survived – doctors discharged Adam after two months.
How did Adam and Anna Bagenholm survive? Researchers believe that several factors play a role. At normal temperatures, the brain continuously consumes oxygen and other nutrients, but at low temperatures, its appetite is significantly reduced. Although extremely cold temperatures slow down important neurological processes, they also inhibit cell death. Bagenholm was trapped in a pocket of air, half submerged in cold water. This way, she can continue to breathe while her body cools to a temperature where the lack of oxygen won't do much harm to the brain.
In fact, doctors have long known that cold temperatures have the ability to protect the body. Surgeons often deliberately lower a patient's body temperature to protect vital organs from damage. For example, during open heart surgery, the heart fills with a fluid called cardioplegia, which cools and stops working. This gives doctors time to work with a heart that is no longer beating while an external machine pumps blood throughout the body.
If we consider induced hypothermia, the lowest temperature a person can withstand without brain damage is about 4 degrees Celsius – this figure was achieved by doctors during an operation in 1961. And this record is unlikely to be broken. Modern medicine recognizes that low body temperature poses many serious risks, so more modern surgical techniques try to avoid hypothermia to avoid side effects.
