Salt sensitivity of blood pressure is accompanied by slow respiratory rate: results of a clinical feeding study.
BACKGROUND: Sleep-disordered breathing has been implicated in hypertension, but whether daytime breathing is a factor in blood pressure regulation has not been investigated to date. The present study sought to determine the role of breathing pattern in salt sensitivity of blood pressure. METHODS AND RESULTS: Thirty-six women, ages 40-70, were placed on a six-day low sodium/low potassium diet followed by a six day high sodium/low potassium diet. Breathing pattern at rest and 24-hr ambulatory blood pressure were monitored at baseline and after each six-day diet period. Respiratory rate (but not tidal volume or minute ventilation) was an inverse predictor of systolic (r = -0.50 p <.001) and diastolic (r = = -0.59; p <.001) blood pressure sensitivity to high sodium intake. Respiratory rate was positively associated with hemoglobin (r = +0.38; p <.01), and the salt-induced change in hemoglobin was associated with salt-induced change in blood pressure (r= -0.35; p <.05). CONCLUSION: These findings indicate that a pattern of slow breathing not compensated by increased tidal volume is associated with salt sensitivity of blood pressure in women. Breathing patterns could play a role in the hypertensive response via sustained effects on blood gases and acid-base balance, and/or be a marker for other biological factors mediating the cardiovascular response to dietary salt intake.
Anderson
David E
DE
Parsons
Beverly A
BA
McNeely
Jessica C
JC
Miller
Edgar R
ER