1. Central and regional haemodynamics and leg metabolism at rest, during and after a prolonged exercise were studied in seven untreated hypertensive males before and after a long-term treatment (6 weeks) with an unselective β-receptor-blocking drug (alprenolol).
2. Alprenolol treatment (200–400 mg, twice daily) decreased arterial blood pressure at rest and during exercise; it reduced heart rate in relation to drug plasma concentrations during and after exercise; it left cardiac output unchanged; it reduced leg blood flow at rest, but had no effect on leg blood flow during exercise.
3. Alprenolol treatment also decreased lipolysis and lactate release in relation to drug plasma concentrations during exercise.