Moderate dietary sodium restriction for 8 weeks in essential hypertension increased muscle sympathetic nerve traffic by 23.0% (P<0.05) and reduced its baroreflex modulation by 46.8% (P<0.01).
Does moderate dietary sodium restriction affect neuroadrenergic and reflex responses in untreated mild to moderate essential hypertensive patients?
Moderate dietary sodium restriction in essential hypertension triggers sustained sympathetic activation and baroreflex impairment, highlighting potential adverse neuroadrenergic effects of this lifestyle intervention.
p-value: p=<0.05
BACKGROUND: In essential hypertension, marked restrictions in dietary sodium intake cause in the short-term period an increase in muscle sympathetic nerve traffic (MSNA) and a baroreflex impairment. The present study was set out to assess on a long-term basis the neuroadrenergic and reflex effects of moderate sodium restriction. METHODS AND RESULTS: In 11 untreated mild to moderate essential hypertensive patients (age 42.0+/-2.6 years, mean+/-SEM), we measured beat-to-beat blood pressure (Finapres), heart rate (ECG), and MSNA (microneurography) at rest and during stepwise intravenous infusions of phenylephrine and nitroprusside. Measurements were performed at regular sodium intake, after 1 and 8 weeks of low-sodium diet (80 mmol NaCl/d), and repeated again at regular sodium intake. After 1 week, urinary sodium excretion was markedly reduced. This was accompanied by a slight blood pressure reduction, no heart rate change, and a significant increase in plasma renin activity, aldosterone, and MSNA (+23.0+/-4.6% P<0.05). Whereas baroreflex heart-rate control was unchanged, baroreflex modulation of MSNA was reduced by 46.8+/-5.1% (P<0.01). At the end of the 8-week low-sodium diet, the neurohumoral and baroreflex responses were similar to the ones observed after 1 week of the dietary intervention. All changes disappeared when regular sodium diet was restored. CONCLUSIONS: Thus, a moderate dietary sodium restriction triggers a sympathetic activation and a baroreflex impairment. Maintenance of low-sodium diet for several weeks does not attenuate these adverse adrenergic and reflex effects.
Grassı et al. (Mon,) conducted a other in essential hypertension (n=11). moderate dietary sodium restriction vs. regular sodium intake was evaluated on muscle sympathetic nerve traffic (MSNA) and baroreflex modulation (p=<0.05). Moderate dietary sodium restriction for 8 weeks in essential hypertension increased muscle sympathetic nerve traffic by 23.0% (P<0.05) and reduced its baroreflex modulation by 46.8% (P<0.01).