A device for continuously monitoring an elevation, α, from horizontal of a backrest against which a backbody of an individual may lean, to provide an automatic notification in the event the elevation, α, falls below a prescribed value. The device to include: (a) a liquid column having an opening to atmosphere at an upper-end, the liquid column contained by a length of tubing encased by an elongated flexible housing extending along at least a substantial portion of the tubing length, and a gas permeable membrane over the opening; (b) a pressure transducer located along the liquid column to take measurements at a position other than the upper-end, the pressure transducer in communication with a computerized unit having at least one alarm for communicating the automatic notification; (c) an entry port into the length of tubing having an open state permitting manual entry of the liquid into the tubing, and a closed-shut state; and (d) a first securing mechanism for attachment of at least the upper-end to the backrest, and a second securing mechanism for attaching the position other than the upper-end to, for example, a seat interconnected with the backrest. The first securing mechanism may, alternatively, be used to directly attach the upper-end to the backbody toward the shoulder region thereof. Further, the liquid column may also comprise a second-end extension at which a pressure transducer is located; the pressure transducer may be integrated with the computerized unit and in communication with one or more alarms.