Responsiveness of the renin-aldosterone system during exercise in young patients with essential hypertension

Abstract. The effect of exercise of gradually increased intensity, i.e. 75 W for 20 min followed by 100 W for 20 min, on plasma renin concentration (PRC) and plasma aldosterone concentration (PAC) was studied in young patients with essential hypertension and normotensive control subjects. During exercise without previous sodium loading PRC and PAC increased to the same degree in both hypertensives and normotensives during light exercise; PRC increased further significantly in the normotensives (63 to 72 μIU/ml (medians), P < 001) but not in the hypertensives (46 to 51 μIU/ml) during heavy exercise. PRC and PAC were significantly correlated during both 75 W (p = 0–633, P<005) and 100 W (p = 0–635, P<005) exercise in the normotensives, but not in the hypertensives. During exercise after loading with 500 ml sodium chloride (0–85 mol/1) PRC and PAC increased in both hypertensives (28 to 42 μIU/ml, P< 0.01; 0.11 to 0.53 nmol/1, P < 001) and normotensives (22 to 33 μIU/ml, P<002; 012 to 0–34 nmol/1, P<00), although to a considerably lower degree than without previous loading. PRC and PAC were, however, significantly higher in the hypertensive than in the normotensive group after exercise. It is suggested that the responsiveness of the renin-aldosterone system is abnormal during exercise in young patients with mild essential hypertension, both without and with previous intravenous sodium loading.