Wally Nelson, an 80-year-old man from Minnesota, found his friend's body in the snow, just a few metres from his Minnesota home, early on New Year's Eve.Jean Hilliard, nineteen years old, had her car stop after returning from a night out to her parents' home. She was dressed in a winter coat, mittens and cowboy boots as she ventured out into the cold night air to find her friend.She fell and lost consciousness. Hilliard's body lay frozen solid for six hours.Nelson would recount the incident years later in a Minnesota Public Radio interview, "I grabbed her by her collar and skidded she into the porch.""I thought she was dead." It was stiffer than a board and I could see bubbles in her nose.Nelson's quick response would have prevented Hilliard from becoming one of the many hypothermia-related deaths each year. Instead, Hilliard's story has been made part of medical history and scientific curiosity.How can a body survive being frozen solid for so long?Although stories of people who have survived freezing temperatures are not common, they are notable enough to make news. Medical specialists in cold climates say that "Nobody is alive until they are warm and dead."Therapy has evolved from the realization that extreme hypothermia does not necessarily mean the end of a person's life. The body can be cooled down and the insatiable hunger for oxygen reduced if it is done under controlled conditions.A chilled body, whether in medical settings or rare cases elsewhere, can slow down the dying process for long enough to deal at least temporarily with a low pulse.Hilliard's account is notable for the extreme nature and severity of her hypothermia.It's not important that her body temperature was only 27 degrees Celsius. This is 10 degrees lower than the average healthy person. It was clear that she was frozen. She was apparently frozen with ashen skin and eyes.George Sather, her physician, described the condition as "cold, solid and just like a piece from meat out of a deep freezer."Hilliard's body was back to normal in just a few hours after being warmed up by heating pads. Hilliard was speaking by noon and was soon discharged with a few blistered toes.It was all due to the power and influence of prayer, her family and friends in her community said. But what does biology say about this matter?Water, unlike many other materials, takes up more volume as a solid than as a liquid. This is bad news for tissues that are exposed to cold temperatures as the liquids in them could expand and cause damage.Even a few stray crystals can cause cell damage if they aren't in the right place. Their needle-like shards can penetrate cell membranes and reduce extremities to blackened patches or muscle. This is what we call frostbite.Some animals have clever adaptations that allow them to cope with sharp, expanding ice crystals under freezing conditions. For example, the Antarctic blackfin icefish, a deep-sea fish, produces glycoproteins as a natural antifreeze.Wood frogs can turn the cells of their bodies into syrup by flooding them with glucose. This prevents freezing and dehydration. Water is free to form solids outside of their cells. This encases tissues in ice, making them appear solid like frog-shaped cubes.It's difficult to know how Hilliard's body survived being frozen without external observations. Did her body have a unique chemistry? Perhaps even her tissue composition.Perhaps. It is important to clarify what "frozen" means in this instance. Hilliard's core body temperature was, despite being low, reportedly well above freezing. It is a vast difference between literal water in the veins and metaphorical "chilled to bone".Hilliard's body feeling solid is a sign of severe hypothermia. As muscle rigidity increases to such an extreme degree, it can even look like rigor mortis, which is the stiffening that occurs to a dead body.It might not be surprising that her body surface was white and cold, and her eyes looked'solid' and glassy. To keep organs working, the body will shut off blood vessels beneath the skin. A body can look ashen or feel remarkably cold.If medical staff are persistent enough to use a smaller gauge hypodermic on constricted veins, especially when they're covered with thin layers of skin that is pressed against rigid muscles, it's possible for us to imagine a bent needle.We don't have much information other than some surprising accounts. It is difficult to speculate if Hilliard's "frozen" body was unusual, shocking or even unique in its ability to withstand such extreme changes of state. It is clear that Hilliard was lucky.We learn more about the incredible feats that the human body can do, and the less we can rely on luck to save lives like hers in future. Instead, we can rely more on medical advances and quick responses.
