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Augmentation of baroreceptor reflex function by oral calcium supplementation in essential hypertension
1Second Department of Internal Medicine, Ehime University School of Medicine, Japan.
Insights
Oral calcium supplementation improved baroreceptor reflex sensitivity and reduced blood pressure lability in hypertensive patients. This suggests enhanced autonomic nervous activity, benefiting cardiovascular regulation.
Area of Science:
- Cardiology
- Hypertension Research
- Autonomic Nervous System Function
Background:
- Essential hypertension is characterized by impaired baroreceptor reflex sensitivity and increased blood pressure lability.
- Autonomic nervous system dysfunction plays a significant role in the pathophysiology of hypertension.
Purpose of the Study:
- To investigate the effects of oral calcium supplementation on baroreceptor reflex function and blood pressure lability in patients with essential hypertension.
- To explore the association between calcium supplementation, autonomic nervous activity, and cardiovascular regulation.
Main Methods:
- A study involving 14 patients with mild to moderate essential hypertension receiving 1.0 g/day of oral calcium for 1 week.
- Baroreceptor reflex sensitivity (BRS) assessed via phenylephrine injection and R-R interval changes.
- Autonomic nervous activity evaluated using coefficient of variation of R-R interval (CVR-R), urinary catecholamines, and blood pressure variability (CVBP).
Main Results:
- Calcium supplementation significantly increased BRS and CVR-R, indicating enhanced baroreceptor reflex and parasympathetic activity.
- No significant changes in 24-h systolic or diastolic blood pressure were observed.
- A significant reduction in blood pressure lability (CVBP) was noted after calcium treatment.
Conclusions:
- Oral calcium supplementation enhances baroreceptor reflex function in hypertensive patients.
- The improvement in baroreceptor reflex sensitivity is partly mediated by increased parasympathetic nervous activity.
- Calcium supplementation effectively reduces blood pressure lability, contributing to better cardiovascular regulation in essential hypertension.
Abstract:
1. We studied the effect of oral calcium supplementation (1.0 g/day) for 1 week on baroreceptor reflex function and the lability of blood pressure in association with the changes in autonomic nervous activity in 14 hospitalized patients with mild to moderate essential hypertension (nine males and five females, mean age of 56 +/- 11.2 (s.d.) years). 2. Baroreceptor reflex sensitivity (BRS) was determined by the change in R-R intervals in response to the pressor response induced by phenylephrine injection. We measured coefficient of variation of R-R interval (CVR-R) and urinary excretion of catecholamines to evaluate the mechanism of change in BRS. We also used coefficient of variation of blood pressure (CVBP) and error of single cosinor analysis as parameters for lability of 24-h blood pressure. 3. The means of 24-h systolic and diastolic blood pressures showed no significant changes after calcium supplementation for 1 week. BRS and CVR-R were significantly increased by calcium supplementation. Daily excretions of norepinephrine and epinephrine corrected by creatinine were unchanged. Both CVBP and error of 24-h systolic blood pressure showed a significant decrease after calcium treatment. 4. These results indicate that oral calcium supplementation augments baroreceptor reflex function, in part through an enhancement of parasympathetic nervous activity, resulting in reduction of the lability of blood pressure in patients with mild to moderate essential hypertension.