Haemodynamic effects of nifedipine in essential hypertension at rest and during exercise.

Fifteen males with previously untreated essential hypertension in WHO stage I, aged 20-64 years were studied on an outpatient basis. Oxygen consumption, heart rate, cardiac in a in a supine and sitting position and during steady state work at 50, 100 and 150 W. Following the haemodynamic study, nifedipine (long-acting form) 40-80 mg daily was given as the sole drug for 3-12 months (mean 11 months) whereupon the haemodynamic study was repeated. Systolic, diastolic and mean arterial pressures fell about 17% at rest supine and sitting and from 15 to 10% at the three different workloads (P less than 0.001). All but one patient demonstrated a fall in mean arterial pressure of 10 mmHg or more. The fall in pressure was associated with a statistically significant (P less than 0.05) reduction in total peripheral resistance (17% during rest and 10 to 16% during exercise). There were no statistically significant changes in oxygen consumption, heart rate, cardiac index or stroke index.