Arteriovenous anastomoses (AVAs) in the face, palms, and soles of the feet allow for rapid heat exchange.

“AVAs are direct connections between the small arteries and the small veins. They bypass the capillaries to some extent. They are little short vessel segments. They have a big, large inner diameter. And they have this very thick, muscular wall.”

“The primary sites of heat loss which we're going to get into are the palms of your hands, the soles of your feet, and the upper part of your face. And the reason these are avenues for heat loss is they're under lane by special blood vessels. And these blood vessels are able to shunt the blood from the arteries which coming from the heart directly to the veins which are returning to the heart and bypassing the capillaries which are the nutrative vessels but high resistance.”