The landlord is wrong. First of all, whether you burn fat or not, it is necessary to drink water during exercise, otherwise it will be harmful to your health. Second, water can't burn instead of fat. Exercise needs energy. First, it will burn your sugar, and then burn your fat, because they all contain energy. But water has no energy. It can't give you the quantity, what to burn and what to burn. Sweating has nothing to do with your fat.