Sweat would naturally seem to be the stuff of strength, vigour, since it is expended when strength, vigour, is expended… In the Torres Straits men drink the sweat of famous warriors in the belief that in it they are getting their valour.
Onians argues that archaic physiology identified sweat with the body’s vital substance, accounting for cross-cultural ritual appropriation of another’s sweat to acquire their strength.
, The origins of European thought about the body, the mind,, 1988thesis