In this consideration we present the results of our investigations on the effects produced by change of posture, when this change is brought about without effort on the part of the subject. It is, of course, understood that in the standing posture there is exerted a constant muscular effort, while in the horizontal posture this element is eliminated.
Our subjects were placed on a table with a movable top. This top was set and balanced so that when the subject was once placed in position, he had no further occasion for voluntary muscular effort. After stepping onto the foot-board of the table, which was about 6 inches above the floor, the arm-pieces of the blood-pressure instruments were attached. The instrument for arterial pressure was of the usual type, mercury column, cuff 10 cm. wide. The apparatus for measuring the venous pressure was that of the type constructed
BARACH JH, MARKS WL. EFFECT OF CHANGE OF POSTURE — WITHOUT ACTIVE MUSCULAR EXERTION—ON THE ARTERIAL AND VENOUS PRESSURES. Arch Intern Med (Chic). 1913;XI(5):485-494. doi:10.1001/archinte.1913.00060290019002