The new iPad overheating and gets hot

I have received my new iPad 4G today. I note that it gets really-really hot/warm after 30minutes of usage. When I hold it in portrait mode, iPad 3 gets instantly hot on the back lower left side where I grip, then it does cool down. The heat is near unbearable at times. My friend also gets the same issue with his new iPad WiFi only.How to fix the heat problems* If you are constantly downloading