The head of the bed (HOB) for a patient is often elevated since it improves comfort and facilitates respiratory functions. However, elevating the HOB essentially causes the patient support surface to turn into a ramp, forcing the patient’s body to slide down. As the patient slides down, weight pressing on the pelvis, the coccyx, and the ischial tuberosities increases, resulting in associated increases in interface pressures. Methods. In an institutional review board-approved study, pressure distribution was measured on volunteers at 4 discrete body positions sliding down in bed on 3 commonly used support surfaces. Results. This study showed the total contact area of the patients decreased as they slid down, resulting in increased pressure, particularly on the sacral area and the heels. The study also confirmed that these pressure increases are persistent and occurred on all of the support surfaces tested. Conclusion. These increases in pressure likely contribute to the development of pressure ulcers.