The aim of this research was to assess whether the antihypertensive therapy with nifedipine, a dihydropyridine calcium-antagonist, is able to control hypertension not only at rest but also during exercise. So, 20 male hypertensive patients, mean age 48 years, were evaluated by symptom limited bicycle exercise (10 W/min) before and after 6 and 12 months of therapy with nifedipine in a slow releasing form (40-60 mg/day). Exercise tolerance significantly increased after 12 months of antihypertensive therapy with nifedipine (from 146 +/- 5 to 153 +/- 4 W, p < 0.05). Systolic and diastolic blood pressure decreased after 6 and 12 months both at rest (from 160 +/- 6/109 +/- 9 mmHg to 132 +/- 3/91 +/- 3 and 135 +/- 4/93 +/- 1 mmHg, respectively, both p < 0.001) and during exercise (at end exercise: from 238 +/- 7/121 +/- 5 mmHg to 216 +/- 6/106 +/- 3 and 213 +/- 6/107 +/- 3 mmHg, respectively, both p < 0.001). No significant changes in heart rate were observed during antihypertensive therapy both at rest and during exercise test. In conclusion, long-term antihypertensive therapy with nifedipine was effective in the control of hypertension both at rest and during physical stress. Moreover, an improvement in effort tolerance was observed in hypertensive patients.