PROTECTS YOUR CRITICAL AREAS. When joints are chilled while also put under stresses, your metabolism demands an especially large quantity of immunity protecting substances, particularly Vitamin C. Without this protection, the affected joint loses its mobility. As a result, the joint starts to swell and the articular cartilage weakens, causing an inflammation and pain due to articular surfaces pushing and rubbing against each other. To prevent this, these critical areas must kept warm. Special 3D structures help to insulate these spots.