Whatever had been happening in her brain during those six hours, it had not produced the visual and experiential phenomena that are sometimes reported by people who have come close to death.

What it had produced — as far as the medical record could establish — was survival.

The Science Of Extreme Hypothermia

To understand how Jean Hilliard might have survived, you have to understand the science of hypothermia at a level beyond the popular summary of “the cold slowed everything down.”

The human body’s normal core temperature — the temperature at the vital organs, maintained by metabolic heat production and the insulating effect of peripheral tissues and fat — is approximately 98.6 degrees Fahrenheit, or 37 degrees Celsius.

The body works very hard to maintain this temperature within a narrow range, because the enzymes and other proteins that drive biological processes have been optimized over millions of years of evolution to work best at exactly this temperature.