I'm not a specialist in the field, but I believe this is simply called 'blood flow' or 'blood circulation' in English.

Internal body temperature (core temperature) is controlled through several processes, including the combined actions of sweat production and the rate of blood flowing through the network of blood vessels within the skin.

In very cold conditions skin blood flow drops very low, retaining heat in the centre of the body and preserving the flow of warm blood to the vital organs within the chest and abdomen and to the brain.
http://www.netdoctor.co.uk/skin_hair/skin_structure_003740.h...

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Note added at 20 mins (2007-10-08 14:23:23 GMT)
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This is also confirmed by Eurodic:
Medische wetenschappen [COM] Volledige ingang
NL bloeddoorstroming
bloedvoorziening
bloedverzorging
doorbloeding
EN blood circulation
blood flow