YSK hands, feet and the upper part of your face are the most effective vectors of heat relief, while draping a cold towel around your neck can actually stop you from cooling down.

Why YSK: "Our bodies have a kind of emergency temperature relief valve. That valve is a special type of blood vessel: they’re called arteriovenous anastomoses. Most arteries and veins connect through a bed of very thin capillaries that bring nutrients and oxygen to cells. AVAs, though, are different. They are direct junctions of arteries and veins, so blood flows through them pretty quickly. And the real key to their heat relief function is they are concentrated in just a few places in the body. We found that in the palm of the hand, the soles of the feet, and the upper part of the face, which are called non hairy skin, there are special blood vessels, and those blood vessels can shunt the blood from the arteries to the veins directly, bypassing the capillaries."

On the wet towel on neck trick: "The reason is the brain has a thermostat that it uses to trigger the body’s natural cooling mechanisms, like sweating or passing blood through those AVAs. That brain region is located near the back of the neck. It uses neck skin temperature, and blood temps in major vessels there, to measure how hot you are. So your cold towel is going to fool the brain’s thermostat into thinking that your body has cooled down. It’s going to shut down all your other natural cooling methods. And you’ll stay uncomfortably and sometimes dangerously hot."