Effect of exercise and of prolonged oral administration of propranolol on haemodynamic variables, plasma renin concentration, plasma aldosterone and c-AMP

Publisher Website
Google Scholar
Abstract
The effect of submaximal exercise upon hemodynamic and biochemical variables was investigated in healthy male subjects, aged 17-27 yr, before and at the end of 2 wk treatment with propranolol (40 mg oral, 3 times/day). Propranolol reduced resting blood pressure [BP] in normal subjects significantly due to a reduction of cardiac output and of systemic vascular resistance. No effect of propranolol on BP was seen during maximal exercise, since a reduced cardiac output was accompanied by increased peripheral resistance. Reduction of cardiac output during exercise can be compensated in part by an increase in stroke volume. Sympathetic activity induced by physical exercise in normotensives increased plasma renin concentration (PRC) and plasma aldosterone (PA) and suppressed urinary excretion of c[cyclic]AMP. PRC returned to basal levels after 45 min. No increase of PRC was observed after exercise in subjects treated with propranolol. Yet increase of PA was not completely suppressed. No direct relation was demonstrated between PRC and the hemodynamic variables before or during administration of propranolol.