Changes in osmotic pressure and ionic concentrations of plasma during muscular work and recovery

Abstract

Changes in the plasma ions and osmolality as a result of exercise under several controlled environmental conditions were investigated. The plasma osmolality rises slightly but significantly during exercise largely because of increases in Na + , K + , Ca ++ , phosphate, lactate and proteinate. These ions are influenced as much by the environmental temperature and humidity as by exercise. When the changes in ion concentration and hence the osmolality of the plasma are small, the total base is better measured by the depression of the freezing point rather than by conductometry. Submitted on May 11, 1959