Effects of angiotensin converting enzyme inhibition and beta-blockade on exercise responses in hypertensive patients

We compared exercise responses in two groups of hypertensive patients treated with an angiotensin converting enzyme (ACE) inhibitor (lisinopril, 20-80 mg/day, n = 17) or a cardioselective beta-blocker (atenolol, 50-200 mg/day, n = 9). Measurements were made at rest and during exercise at 25 W (2.7 mets) and at 50 W (3.8 mets) on a bicycle ergometer (where mets is exercising oxygen consumption/resting oxygen consumption) after 4 weeks of placebo, and again after 12 weeks of drug administration. Both drugs reduced (P less than 0.05) mean arterial pressure. Atenolol caused significant decreases in the heart rate (approximately 25%) and cardiac output (approximately 26%; Defares CO2 rebreathing), and significant increases in total peripheral resistance (approximately 30%) and arteriovenous O2 content (approximately 20%). Lisinopril decreased (P less than 0.05) stroke volume. At the same exercise intensity systolic blood pressure, arteriovenous O2 and total peripheral resistance were lower (P less than 0.05) and the heart rate was higher (P less than 0.05) after lisinopril than after atenolol. After the treatment of hypertension with the ACE inhibitor the responses to exercise were less restrictive than those after treatment with the cardioselective beta-blocker.