The sun is well known to cause free radical damage to your skin but did you know that exposure by other forms of heat can also wreak havoc on your skin. Excessive heat by ovens, heaters and fireplaces can cause inflammation and collagen breakdown.   A study by Seoul National University College of Medicine found that just 30 minutes of heat exposure three times a week can be enough to change your skin after six weeks as it causes protective antioxidant levels in the skin to drop and genes to create MMP proteins that break down collagen and cause wrinkles. To help combat exposure to heat use moisturizers or makeup that contain minerals like titanium dioxide, zinc oxide, iron oxides, or kaolin. These ingredients can act as physical blockers against infrared heat and can protect your skin from damage.