:this:

Most mattresses aren't designed to be put on the floor and the springs/foam will get all fucked up because the floor has absolutely no give, and it will be very uncomfortable. Also please get a waterproof mattress protector/cover so your sweat doest soak through your sheets and into the mattress you sleep on every night. If you really want to sleep on the floor get a Japanese style Futon bed and air it out daily to prevent mold and mites. Or at least use a waterproof mattress protector