Arteriovenous anastomoses (AVAs) are special blood vessels in areas like your palms that connect arteries (which carry blood from the heart) directly to veins (which return blood to the heart). Unlike normal capillaries, these vessels allow a large amount of blood to flow quickly, which helps release or retain heat. This makes AVAs important for controlling your body temperature efficiently.

Glabrous skin is the smooth, hairless skin found on the palms of your hands, soles of your feet, and fingertips that contain the specialized blood vessels — AVAs. When the palms are cooled, the blood in these vessels loses heat quickly, and this cooler blood circulates back into the body, lowering core temperature.

This rapid cooling reduces thermal strain on muscles and organs, delays fatigue, and improves overall physiological performance. By preventing overheating, palm cooling also helps maintain focus, muscle output, and endurance — especially during intense exercise or in high-temperature environments.