The effect of tiring the forearm muscles in different ways on venous blood pH, P CO 2 and standard bicarbonate

1. The changes in venous blood pH, p CO 2 and standard bicarbonate caused by tiring the forearm by ( a ) rhythmic work with free circulation, ( b ) rhythmic work with ischaemic circulation, were determined using the Astrup apparatus. 2. For rhythmic work, opening and shutting the hand as quickly as possible for 2 min, the averaged results on six subjects were: pH fell 0·19 units; p CO 2 (after full oxygenation of venous blood) rose 52 mm Hg; standard bicarbonate fell 2·9 m‐equiv/l. 3. For rhythmic work during ischaemia and accompanied by pain, the averaged results on six subjects were: pH fell 0·19 units; p CO 2 (after full oxygenation of venous blood) rose 26 mm Hg; standard bicarbonate fell 6·3 m‐equiv/l. 4. These results are compared with those obtained in an earlier investigation on the effect of strong hand grips for 1 min.