The effect of mental arithmetic in normotensive and hypertensive subjects, and its modification by beta-adrenergic receptor blockade

Abstract

1 The effects of a 5-min period of sustained mental arithmetic upon blood pressure and heart rate were determined in several groups of healthy subjects and hypertensive patients. 2 The arithmetic produced significant increases in heart rate and blood pressure (both systolic and diastolic) in both normotensive and hypertensive subjects. 3 The blood pressure changes were neither attenuated nor enhanced by the prior administration of basis. 4 In subjects habituated to the test the heart rate increase was unaffected by the drugs, but in those less familiar with the test it was usually attenuated. 5 Although the beta1-adrenoceptor selective blocker, metoprolol, caused decreases in baseline values for blood pressure and heart rate similar to those observed with the use of the two non-selective blockrs, it was shown in a double-blind crossover comparison with propranolol that the haemodynamic changes provoked by the mental arithmetic were not less in the presence of beta1-receptor blockade than when both beta1- and beta2-receptors were blocked. 6 These findings suggest that, during beta2-adrenoceptor blockade, the haemodynamic effects of minor mental stress are not exaggerated because of uncompensated alpha-receptor mediated vasoconstriction, such as occurs following adrenaline infusion.