Abstract

To study the influence of beta-1-selective (atenolol) and beta-1.2-nonselective (propranolol) blockers on the cardiovascular responses to isokinetic exercise (peak torque production), 21 clinically normal male and female subjects (ages 19 to 31 years) were administered either a placebo or a low or high dose of atenolol or propranolol. Placebo (100 and 200 mg daily), atenolol 50 and 100 mg daily), or propranolol (10 and 20 mg four times per day) were administered for 8 days. Placebo washout periods of 4 days occurred between drug administrations. Subjects performed the sitting press and the squat to stand exercises at 25 and 100 rad/s on the Ariel Computerized Exerciser prior to and at the end of each dosing regimen or washout period. A group trial analysis of variance with repeated measures on trials was used to interpret the data. Post hoc tests were used to determine where significant differences occurred. Beta-blockade was evident by the significant blunting heart rate and systolic pressure at rest and at peak exercise with both atenolol and propranolol. There was no drug effect for the peak torque data of the 10 repetitions of isokinetic exercise. Conclusion: Beta-blockade does not interfere with the isokinetic peak torque production during times in which heart rate and systolic pressure are blunted. Healthy people administered beta-blockers for such circumstances as migraines, anxiety, glaucoma, or heart palpitations should be able to participate in resistance exercise without a drug-related effect on strength performance. Verf.-Ref.