The body reacts to cold and heat by adjusting the blood stream to different parts of the body, like hands, fingers and feet. But the body can not adjust the blood stream to your head. This to ensure the brains function during all conditions. That is why the colder it gets, the more heat you loose from the head by radiation, or even worse, by conduction in the water. Up to 60% of body heat is radiated away from the head. You stay warmer with an effective, used by a hood that fits you. Therefore, Alpha Diving has a wide range of different hoods that meet all requirements and wishes for diving in all conditions regardless of whether your next experiences to happen in ice-cold or tropical water. You keep warmer with an effective hood.