This study was undertaken to clarify the effects of exercise on the cardiovascular, renal function and plasma humoral changes. The results obtained were as follows ; 1. Plasma renin activity and aldosterone concentration were significantly increased after exercise. 2. Plasma levels of cortisol, ACTH, β-endorphin and insulin were not changed. 3. Plasma levels of electrolytes were not changed, but hematocrit was significantly decreased after exercise. 4. Urinary excretion of potassium was increased. 5. Mean arterial blood pressure and heart rate were significantly increased during the exercise.