Those who maintain the Paleo lifestyle of cavemen are now saying they prefer sleeping on floors rather than mattresses. Paleo advocates claim sleeping on the floor is just as comfortable, can correct posture, improve circulation, help you sleep deeper, and rid nagging aches and pains. While there may be some merit to these claims, they are not entirely right or wrong. Milton Marvin Ang Chua, MD from the University of Utah, says how much and how fast you fall asleep is what matters most, and being comfortable is crucial in determining that.
So if you are comfortable on the floor, knock yourself out. He would also recommend not sleeping on a floor to help pain due to the potential of muscle degradation over time. It appears Paleo people must take the good with the bad when it comes to the floor.