Changes of dopamine and atrial natriuretic factor by mild exercise for hypertensives.

Changes of humoral factors related to the regulation of fluid volume were investigated in exercise training for hypertensives. Twelve patients with essential hypertension were treated with an aerobic exercise for 10 weeks. A significant reduction in blood pressure from 161 +/- 3/100 +/- 2 mmHg at week 0 to 142 +/- 5/94 +/- 3 mmHg at week 4 was observed which continued until week 10. Urine dopamine was increased significantly at the 4th week from 386 +/- 29.4 micrograms/day at week 0 to 524 +/- 46.3 micrograms/day and plasma atrial natriuretic factor (ANF) was significantly reduced at the 4th week, from 41.5 +/- 2.7 pg/ml at week 0 to 32.6 +/- 3.7 pg/ml. Plasma volume was found reduced significantly from 2,531 +/- 166 ml/m2 at week 0 to 2,221 +/- 165 ml/m2 at week 10. These results suggest that the increase of dopamine and reduction of plasma ANF which took place at the early stage might be related to, at least in part, the depletion of plasma volume and the reduction of blood pressure in mild exercise for hypertensives.