Heart rate and blood pressure interactions during attempts to consciously raise or lower heart rate and blood pressure in normotensive subjects

This study investigated the interaction between heart rate (HR) and blood pressure (BP) during conscious control under visual biofeedback and background noise conditions. Normotensive volunteers were instructed to (i) decrease and (ii) increase HR (group A, n = 16) or BP (group B, n = 16). After instructions to lower HR or BP there was no significant change in HR or BP for either group. After instructions to raise HR, HR increased significantly (13.8 +/- 1.3 beats min(-1), P < 0.0001) and BP did not change. However, following instructions to raise BP, both HR and BP increased significantly: systolic BP (5.2 +/- 1.5 mmHg, P < 0.001), diastolic BP (3.5 +/- 0.9 mmHg, P < 0.001) and HR (8.6 +/- 1.3 beats min(-1), P < 0.0001). Biofeedback and background noise did not alter the relative change in HR or BP. In conclusion, normotensive subjects were unable to reduce BP or HR under conscious control. Subjects were able to increase both HR and BP, and voluntary increases in HR did not alter BP, while voluntary increases in BP also increased HR indicating distinct HR/BP interactions during conscious control.