Effects of beta-blockade and exercise on cardiovascular and cognitive functioning.

Twenty-four men with mild essential hypertension were assigned randomly to receive propranolol (n = 9), atenolol (n = 7), or a placebo (n = 8). All subjects participated in a 12-week study and provided physiological and behavioral data four times during the study: after a medication-free baseline period (Session 1); after 2 weeks of medication, without exercise (Session 2); after 8 weeks of continued medication while participating in a program of aerobic exercise (Session 3); and after 2 weeks of maintenance exercise without medication (Session 4). Subjects' maximal oxygen uptake increased significantly between Sessions 2 and 3, and the magnitude of this increase did not vary across the drug groups. Subjects' resting heart rates varied as a function of the presence of beta-blocking medication, but there was in addition a reduction attributable to exercise training that did not vary across the drug groups. The decrease in blood pressure associated with beta-blockade (Session 2) was not decreased any further by exercise training (Session 3). Despite an increase in blood pressure following the withdrawal of active medication (Session 4), blood pressure remained significantly lower compared with the Session 1 baseline level. Performance in a reaction-time test of short-term memory functioning improved slightly for all three groups between Sessions 1 and 2 and remained constant thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)