Abstract des Autors

The effects of long-term (6 months) antihypertensive treatment with three different types of beta-blockers (propranolol, nonselective without ISA; pindolol, nonselective with ISA; metoprolol, beta1-selective without ISA) on submaximal exercise capacity and metabolic variables during submaximal endurance exrcise were studied in seven subjects with essential hypertension. Exercise tests were performed on a bicycle ergometer at 70 of estimated VO2max. Similar reductions of resting and exercise blood pressure and exercise heart rate were obtained with the three beta-blockers. Exercise time was significantly reduced by all three beta-blockers during chronic antihypertensive therapy. The reduction tended to be more pronounced after 5-6 months of treatment than after 1 week (P=0.06). During exercise, the plasma glycerol and nonesterified fatty acid concentrations were reduced. Plasma glucose concentration was reduced at the end of the exercise test during propranolol treatment only. Plasma lactate concentrations tended to be increased, but the difference was significant during pindolol treatment only. Oxygen uptake tended to decrease and respiratory exchange ratio to increase. Plasma potassium concentrations during exercise were significantly increased with all three beta-blockers. The effects on the metabolic variables during exercise were similiar after 1 week and during long-term (20/24 weeks) beta-blocker treatment. The study shows that submaximal endurance exercise capacity is impaired in patients with essential hypertension on beta-blocker therapy and that the impairment is maintained during long-term antihypertensive beta-blocker treatment. Verf.-Referat