US Patent 7007327 Adjustable bed

To provide an adjustable bed that assists a user to turn comfortably in his or her sleep without mental stress. Once an automatic mode starts, measurement on the depth of sleep of the user lying on the bed is launched. The depth of sleep is measured by detecting biological information such as brain waves, heart rate, and respiratory rate of the user using electrode sensors or the like, and analyzing the biological information according to a polysomnography method or the like. If the depth of sleep is 0, i.e., the user is in REM sleep, and if one hour or more has passed since the measurement is launched or since an immediately preceding turn operation, a turn operation is performed to turn the user.