PLASMA-VOLUME CHANGES IN RESPONSE TO RESISTIVE EXERCISE

The present study was designed to determine the cumulative effects of a series of four resistive exercises on intravascular plasma volume throughout one exercise session. Seven healthy males, mean (+/- SE) age 26.7 +/- 1.2 y, participated in the study. In two separate trials the subjects' one-repetition maximum (1-RM) and 10-RM were determined. In a third session, an IV catheter was inserted into a forearm vein at 0800 h and kept patent with a heparin lock. At 0940 h three sets of bench press (BP), lat pull (LP), leg extension (LE), and leg curl (LC) were executed at a 10-RM load for 10 repetitions or until failure. Blood samples were collected before (-30, 0), during (after BP, LP, LE, LC), and after [5 min, 15 min, and 25 min into recovery (R5, R15, R25)] the resistive exercise session. Plasma volume was reduced as much as -13.35% at LE and returned to normal after R15. We conclude that plasma volume is substantially reduced after performing a short session of upper and lower body resistive exercises. The findings demonstrate the magnitude of resistive-exercise-induced plasma volume loss and underscore the importance of accounting for plasma volume change when determining response of a particular blood parameter to resistive exercise.