Changes in total plasma content of electrolytes and proteins with maximal exercise.

To determine to what extent the increases in concentration of plasma proteins and electrolytes with short maximal work were a result of hemoconcentration, the changes in plasma volume and total content of the plasma constituents were simultaneously evaluated. The results obtained from six human subjects indicated that in comparison to preexercise values there was a net decrease in total content of plasma protein, sodium, and chloride in the first 2 min of the postexercise period, due primarily to a significant loss (13-15%) of plasma fluid. The total plasma potassium content was increased immediately after exercise but was significantly below the preexercise plasma content after 2 min of recovery.