How does vasoconstriction keep you warm?

When we are too hot, blood vessels supplying blood to the skin can swell or dilate (vasodilation). When we are too cold the blood vessels supplying warm blood to the skin become narrow or constrict (vasoconstriction). This reduces the flow of warm blood near the surface of the skin, and reduces heat loss.

Subsequently, one may also ask, how does vasodilation cause us to lose heat?

Sweat secretion stops when body temperature returns to normal. Blood vessels supplying blood to the skin can swell or dilate - called vasodilation. This causes more heat to be carried by the blood to the skin, where it can be lost to the air. Blood vessels can shrink down again - called vasoconstriction.

Why does vasoconstriction happen?

Once homeostasis is restored, the blood pressure and ATP production regulates. Vasoconstriction also occurs in superficial blood vessels of warm-blooded animals when their ambient environment is cold; this process diverts the flow of heated blood to the center of the animal, preventing the loss of heat.

What is vasodilation and why does it occur?

Vasodilation caused by relaxation of smooth muscle cells in arteries causes an increase in blood flow. When blood vessels dilate, the blood flow is increased due to a decrease in vascular resistance. Therefore, dilation of arteries and arterioles leads to an immediate decrease in arterial blood pressure and heart rate.