Plasma volume change during heavy-resistance weight lifting.

Blood samples were obtained from six young men before, and over a 60-min period following a bout of heavy-resistance weight lifting to determine changes in plasma volume. Weight lifting consisted of three sets of four exercises (arm curl, bench press, bent-arm row, and squat) performed using 70% of one-repetition maximum for as many repetitions as possible. Plasma volume change was determined from haematocrit and haemoglobin concentration. During weight lifting, mean oxygen uptake and heart rate were 1.96 L X min-1 and 158 bt X min-1, respectively. Plasma volume was decreased -14.3% (p less than 0.05) immediately following exercise and -7.0% (p less than 0.05) at 15 min into recovery, but had returned to the resting level within 30 min. It was concluded that heavy-resistance weight lifting elicits a significant decrease in plasma volume, which is similar in magnitude to that observed during running and cycling at 80-95% of maximal oxygen uptake.