Respiratory psychophysiology in hypertension research

The pathogenesis of hypertension results from an interaction of genetic and environmental factors. Behavioral factors might participate in sodium sensitive forms of hypertension via a cascade of physiological responses triggered by conditioned inhibition of breathing. When an individual decreases ventilation sufficient to increase pCO2 but not sufficient to activate chemoreceptor reflexes, plasma pH decreases transiently to stimulate a renal mechanism that can expand plasma volume via sodium retention. The combination of high resting pCO2 and high sodium intake elevates resting blood pressure in laboratory animals and healthy human participants. In the natural environment, this mechanism seems to be more important for the development of hypertension in women than in men, perhaps due to differential expression of anger and aggression. Studies are needed to clarify the role of breathing pattern in individual differences in resting pCO2 and the effects of breathing interventions on salt sensitivity and sodium sensitive forms of hypertension.