ActionHeat AA Men's Battery Heated Gloves

The product has issues with staying heated for a long time, why won’t this item keep your hands warm, I believe I read somewhere in the description that the gloves can keep your hands warm for up to 4 or 5 hours. But my gloves won’t do that and once you use the AA batteries once you can’t use them again be cause the gloves won’t produce adequate heat why is that…?