It slows the dying process enough that tissues can survive conditions that would be lethal at normal body temperature.

The clearest illustration of this principle comes from cardiac surgery.

Heart surgeons routinely induce hypothermia in patients undergoing certain complex procedures — cooling the body to allow the heart to be stopped temporarily while work is done on it, because the cooled brain and other organs can tolerate the absence of blood flow for much longer than they could at normal temperature.

Surgeons regularly cool patients to 64 or even 59 degrees Fahrenheit (18 or 15 degrees Celsius) during certain procedures — temperatures that would normally be associated with cardiac arrest and brain death — and these patients survive and recover with normal function because the cold has protected their cells during the period of reduced blood flow.