Arterial pressure oscillations are not associated with muscle sympathetic nerve activity in individuals exposed to central hypovolaemia

摘要

Non-technical summaryThe body adjusts the level of sympathetic nervous system activation to regulate blood pressure in health and disease. Therefore, knowing the level of sympathetic activation is important to treat patients with abnormal sympathetic nervous system function. Directly measuring sympathetic activation is difficult, however, and not possible in most clinical settings. Previous investigators have shown that the variability in blood pressure increases during sympathetic activation. To determine if this is a good non-invasive index of sympathetic activation, we compared blood pressure variability to the direct measurement of sympathetic activation in healthy humans. We activated the sympathetic nervous system by redistributing blood volume away from the head and brain, which also occurs with prolonged standing or haemorrhage. We show that the relationship between variability in blood pressure and sympathetic activation is not the same in all individuals, indicating that blood pressure variability cannot be reliably used to measure sympathetic activation.