Decreased exercise capacity in mild essential hypertension: Non-invasive indicators of limiting factors

Available data suggest that exercise capacity is limited in hypertension. The mechanism of this reduced maximal exercise capacity has not been fully elucidated. In this study 22 patients with mild essential hypertension (162 ± 22 mmHg systolic and 95 ± 8 mmHg diastolic) and 36 normotensive control subjects (128 ± 13 mmHg systolic and 80 ± 7 mmHg diastolic) (P < 0.01) performed an ergometer test till exhaustion. Body mass index in the two groups did not differ. The maximal oxygen consumption VO₂ was lower in the hypertensive group (18 ± 7 versus 23 ± 8ml/kg/min; P < 0.02) as was the maximal workload (141 ± 52 vs. 185 ± 70 Watt; P < 0.01). Rate pressure product rose only 2.7 fold in hypertensive patients versus 3.5 fold in the control group (P < 0.001). In hypertensive patients maximal workload decreased with increasing resting systolic blood pressure (P < 0.05) while in the normotensive subjects maximal workload rose with increasing resting systolic blood pressure (P < 0.05). In conclusion both high and low blood pressure was associated with a decreased maximal voluntary exercise capacity. Even mild hypertension was accompanied by lower maximal exercise capacity. Hypertensive patients also had a lower maximal VO₂ and lower maximal rate pressure product than did normotensive subjects.