Lowest body temperature (intentional)

The lowest temperature to which a living human being has been intentionally cooled is 9°C (48.2°F) by doctors treating a case of ovarian cancer in a 51-year-old woman in Minnesota, USA. On 28 December 1955, the patient’s heart rate was slowly decreased until cardiac standstill was reached. During this time, her body was cooled and remained at this temperature – supported by an artificial respirator – for one hour. She was revived and suffered no ill effects from the experience.

Inducing hypothermia to assist in medical operations has a long history, with the discovery that the circulatory system can he slowed or stopped at low temperatures. The patient here was identified only as case AH #211243 of the Ancker Hospital in St Paul, Minnesota, and the details of her cooling were published in the Annals of Surgery (February 1958). Her heart rate dropped to four beats per minute during the initial cooling stage, when her body temperature - measured by both a rectal thermometer and an electric probe - reached 11.2°C (52.1°F); at 10.5°C (50.9°F), the heartbeat ceased, and the temperature continued to drop until it registered a low of 9°C (48.2°F). While profound hypothermia formed the basis of this patient's treatment at this time - and the cooling procedure was successful - her metastasizing cancer did not regress, and she died 38 days afterwards.