Background Exercise improves physiological function and may improve mood. Some psychologists suggest that mood changes are mediated predominately by self-efficacy rather than physical ability. We examined self-efficacy, mood, aerobic power, and strength in men undergoing exercise training and antihypertensive therapy of calcium-channel and beta-blocking drugs. Because beta blockers limit the physiological benefits of exercise, we evaluated psychological responses independent of physiological gains. Methods Fifty-one men (25–59 years) with mild hypertension were randomized to diltiazen (calcium-channel blocker), propranolol (beta-blocker), or placebo. Subjects completed 10 weeks of circuit weight training, and walking, jogging, or cycling. Study variables included Profile of Mood States (POMS), self-efficacy (SE) for arms and legs, maximal oxygen uptake, and maximal strength for arm and leg exercises. Results Baseline aerobic power, POMS, and SE scores were unrelated. POMS did not relate to strength. Arm SE related to arm and leg strength. Leg SE related to leg strength only. After training, aerobic power increased in the diltiazem and placebo groups, but not in the propranolol group. Strength, and arm and leg SE increased in all groups. After training, POMS tension/anxiety and total mood disturbance decreased and vigor/alertness increased in all groups. Gains in aerobic power and strength were not related to mood or SE changes. Results Tension/anxiety, depression/dejection, confusion/bewilderment, and total mood disturbance changes related to SE changes. Conclusions Thus, psychological changes were unrelated to physical ability. Self-efficacy and several mood dimensions were related. The data suggest that changes in mood may be mediated by changes in perceived abilities.