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

We compared exercise responses in two groups of hypertensive patients treated withan angiotensin converting enzyme (ACE) inhibitor (Iisinopril, 20-80 mg/day, n = 17) or a cardioselective l3-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/rest ing oxygen consumption) after 4 weeks of placebo, and again after 12 weeks of drug administration. Both drugs reduced (P < 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 (appro ximately 30%) and arteriovenous O2 content (approximately 20%). Lisinopril decreased (P < 0.05) stroke volume. At the same exercise intensity systolic blood pressure, arteriovenous O2 and total peripheral resistance were lower (P < 0.05) and the heart rate was higher (P < 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 l3-blocker.