Abstract

We used intense intermittent exercise to produce a 10 expansion of plasma volume (PV) within 24 h and tested the hypothesis that PV expansion is associated with an increase in plasma albumin content. The protocol consisted of 8 4-min bouts of exercise at 85 VO2max with 5-min recovery periods. PV, plasma concentrations of albumin and total protein (TP), and plasma osmolality were measured before and during exercise and at 1, 2, and 24 h of recovery. During excercise, PV decreased by 15, while plasma TP and albumin content remained at control levels. At 1 h of recovery, plasma albumin content was elevated by 0.17+/-0.04 g/kg bwt, accounting for the entire increase in plasma TP content. PV returned to control level at 1 h of recovery without fluid intake by the subjects, despite a 820+/-120-g reduction in body weight. At 2 h of recovery, plasma TP content remained significantly elevated, and plasma TP and albumin concentration were significantly elevated. At 24 h of recovery, PV was expanded by 4.5+/-0.7 ml/kg bwt (10+/-1), estimated from hematocrit and hemoglobin changes, and by 3.8+/-1.3 ml/kg bwt (8+/-3), measured by Evans blue dye dilution. Plasma albumin content was increased by 0.19+/-0.05 g/kg bwt at 24 h of recovery. If 1 g of albumin holds 18 ml of water, this increase in plasma albumin content can account for a 3.4-ml/kg body wt expansion of the PV. No significant changes in plasma osmolality occurred during recovery, but total plasma osmotic content increased in proportion to PV. Verf.-Referat (gekuerzt)