While researching the battle of Turnham Green, I found this article about William Harvey’s observations at Edgehill in the British Medical Journal. Harvey’s experiments early in the 17th century redefined the role of the heart and the circulation. He attended Edgehill and the rest of the 1642-3 campaign with the Royal Army as the king’s personal physician.
Military medics in the Falkland/Malvinas unpleasantness in the 1980s made similar observations (Smith, J Surgeon Commander. Commentary on military cold injury, Journal Army Medical Corps, 1984; 130: 89-96)
I’ve reproduced the BMJ article in its entirety.

BMJ. Dec 11, 1999; 319(7224): 1561.
PMCID: PMC1117270

William Harvey, hypothermia, and battle injuries

I was interested to note that the high survival rate among exanguinated battle casualties in the Falklands conflict was partly attributed to the coldness of the climate, which may have facilitated clot formation and induced a form of suspended animation. A BBC documentary, Living Proof, on 28 September 1999 included a detailed discussion of these effects. The phenomenon, however, had been noted previously by our greatest physician, William Harvey, author of De Motu Cordis (1628). Harvey was present at the Battle of Edgehill (1642), the first battle of the English civil war. According to Aubrey: “He told me that Sir Adrian Scrope was dangerously wounded there, and left for dead amongst the dead men, stript; which happened to be the saving of his life. It was cold clear weather, and a frost that night; which staunched his bleeding, and at about midnight, or some hours after his hurte, he awaked, and was faine to draw a dead body upon him for warmth-sake.” Harvey was also familiar with the best way of raising body temperature: “I remember he kept a pretty young wench to wayte on him, which I guess he made use of for warmth-sake as King David did, and he took care of her in his Will.”

1  Aubrey’s Brief Lives, edited by Oliver Lawson Dick. London: Penguin Books,1949:211-5.

Further reading