[The influence of a long-term cardioselective and noncardioselective beta-receptorblockade on blood pressure, O2-uptake and carbohydrate metabolism. Ergometric investigations in hypertensive patients (author's transl)].

1. In 9 male hypertensives the influence of a long-term cardioselective (200 mg Metoprolol) and non-cardioselective (15 mg Pindolol) beta-receptor blockade on the blood pressure, O2-uptake and carbohydrate metabolism was investigated at rest and during a short (6 min, 100 Watt), long (30 min under steady-state conditions with a heart rate of 130/min) and maximal ergometric work and 5 min after that. 2. In this cross-over trial the blood pressure was reduced significantly (p less than 0.01) and in an identical manner by both beta-receptor blockers. 3. Though there was a significant (p less than 0.01) reduction of the heart rate of 26% by Metoprolol (M) and of 21.2% by Pindolol (P), the O2-uptake during submaximal work was unchanged under P with 1.66 +/- 0.4 l/min and under M with 1.7 +/- 0.44 l/min in comparison with the control (C) of 1.71 +/- 0.38 l/min. The maximal O2-uptake was insignificantly reduced by Pincolol (C 2.51 l/min; M 2.46 l/min; P 2.11 l/min). 4. Only under Pindolol we found in all patients a marked and insignificant (p less than 0.01) drop of the blood sugar level in the 30th min of ergometric work (C 76.2 +/- 11; M 72.6 +/- 9; P 55.3 +/- 11 mg/dl), under maximal work (C 74 +/- 12; M 73.2 +/- 10; P 54.2 +/- 11 mg/dl) and 5 min after (C 83.6 +/- 11; M 87.6 +/- 15; 69 +/- 19 mg/dl). 5. The lactic acid level showed under both beta-receptor blockers the same tendency to decrease. 6. The drop of the blood sugar to hypoglycemic values is due to an impaired glycogenolysis in the skeletal muscles and implies a considerable reduction of the physical capacity. Therefore the cardioselective beta-receptor blocker Metoprolol is recommended especially for the treatment of young hypertensives and for all patients who need their physical fitness in order to achieve their work or to perform a preventive and rehabilitative training.