Summary: To determine the differences in sweat composition between sweat induced by thermal stress alone and that induced by physical exercise, seven young healthy men first sat in a hot room and then performed running exercise. A 20-minute stay in a climate chamber at 40°C resulted in a 5 % reduction in body weight. The same body weight loss was induced by running exercise. Both sodium and chloride concentrations were much lower in the sweat induced by thermal exposure than that induced by the running exercise (p <0.01), while urea nitrogen and creatinine concentrations were significantly higher after thermal exposure than after the running exercise (p <0.01). Potassium concentrations did not differ significantly with either procedure. These findings suggest that sweat composition varies with the kind of induction and that more salt seems to be lost through exerciseinduced sweating than by just sitting in a hot environment.

No abstract

This study was designed to clarify the relationship between the change in H⁺ and the nucleoside concentration at a constant coronary flow rate using a Langendorff system. Wistar rat hearts were perfused with Krebs-Henseleit solution (control, pH 7.4) modified to be either acidotic or alkalotic. Coronary perfusion presssure (CPP), left ventricular pressure, and myocardial oxygen consumption were decreased in the acidotic perfusate. On the other hand, these parameters increased in the alkalotic perfusate. Adenosine production in the acidotic perfusate significantly decreased while it significantly increased in the alkalotic perfusate. Furthermore, there was a significant positive correlation between both the percent change in adenosine production and the percent change in CPP in acidosis and alkalosis. It is suggested from these results that the hydrogen ion affects the adenosine metabolism and that the change in coronary blood flow by H⁺ is at least partly regulated by adenosine.