Approximately five to ten minutes after the start of cold exposure, the blood vessels in the extremities will suddenly vasodilate.
This is probably caused by a sudden decrease in the release of neurotransmitters from the sympathetic nerves to the muscular coat of the arteriovenous anastomoses due to local cold.
The other responses observed in the fingers after immersion in cold water are a continuous state of vasoconstriction, slow steady and continuous rewarming and a proportional control form in which the blood vessel diameter remains constant after an initial phase of vasoconstriction.
However, the vast majority of the vascular responses to immersion of the finger in cold water can be classified as the hunting reaction.
People who live or regularly work in cold environments show an increased response.