In addition, the bed of Burmese rosewood belongs to hardwood bed, while the spine of normal people is straight. Seen from the side, the spine has four physiological bends and looks like an "S" shape. The basic requirement for the bed is to maintain the normal physiological state of the spine, keep the back view straight and the side view physiologically curved. However, sleeping in Simmons bed, no matter which posture you take, is easy to sink and not easy to turn over. Moreover, the middle part of the body always sinks, which changes the normal physiological state of the spine, relaxes the muscles on the upper side of the body and passively tightens the muscles trapped in the buffer part.