Haemodynamks of Recovery after Strenuous Exercise in Physically Trained Hypertensive and Normotensive Subjects

Abstract

1. Central and peripheral post-exercise haemo-dynamics were studied in 18 physically trained male subjects (10 hypertensive and eight normotensive) engaging in sports activities for 3–5 h/week. After a preliminary multistage bicycle ergometric test to evaluate their maximal oxygen consumption and anaerobic threshold, they underwent prolonged exercise at anaerobic threshold in the semi-supine position at 30% grade until exhaustion (mean duration 60.0 + 16.7 min in the normotensive subjects and 61.0 + 5.7 min in the hypertensive subjects, not significant). During the recovery time, intra-arterial blood pressure, echocardiographic cardiac output and indium-gallium strain-gauge plethysmographc peripheral flow were measured, and total, forearm and leg peripheral resistances were calculated respectively from mean blood pressure/cardiac output and mean blood pressure/peripheral resistance. 2. Systolic blood pressure was decreased during the entire recovery period in comparison with the baseline values (−8.4 mmHg, −43.8 mmHg and −39.7 mmHg at the 1st, 5th and 10th min in the hypertensive subjects, P = 0.001, P = 0.0001 and P = 0.0001 respectively; −18.8, −25.5 and −24.1 mmHg in the normotensive subjects, not significant, P = 0.01 and P = 0.01, respectively) without any significant difference between the two groups, whereas the reduction in diastolic blood pressure was not statistically significant. Peripheral flow increased and peripheral resistance decreased in parallel in the forearm and the leg and showed similar trends in the hypertensive subjects and the normotensive subjects. The increase in cardiac output and left ventricular ejection fraction and the decrease in total resistance were also similar in the two groups. 3. In conclusion, after long-lasting strenuous leg exercise central and peripheral haemodynamics vary to the same degree in hypertensive and normotensive trained subjects. Peripheral haemodynamics (similar in the leg and the arm in both groups) closely reflect systemic haemodynamics. The blood pressure reduction observed in the recovery period is totally due to the fall in systemic vascular resistance, while cardiac output is increased.