Blood levels of some electrolytes and hormones during exercise in athletes.

Athletes (8 trained medium and long distance runners) have been explored before and after physical exercise under two testing procedures. After the ergometric test significant increases of Ca++ and Mg++ in serum and significant decrease of Mg++ in erythrocytes occurred. A marked increment of the cortisol level and lesser changes of the thyroid hormones have been found. After the specific training program, apart from the significant reduction of the erythrocyte Mg++, a very significant increase of the cortisol level and large increments of T3 occurred. All subjects showed good coping resources, with inter-individual differences for other three psychological variables.