Normobaric hypoxia conditioning reduces blood pressure and normalizes nitric oxide synthesis in patients with arterial hypertension

Abstract

Insufficient production and/or increased decomposition of the potent endogenous vasodilator nitric oxide plays an important role in development and progression of arterial hypertension and its complications. One of the most effective means of stimulating endogenous nitric oxide synthesis is controlled adaptation to hypoxia. This study examined the effect of a 20-day, intermittent, normobaric intermittent hypoxia conditioning (IHC) program on blood pressure (BP) and nitric oxide production in patients with stage 1 arterial hypertension. The IHC sessions consisted of four to 10 cycles of alternating 3-min hypoxia (10% FIO2) and 3-min room air breathing. BP was monitored for 24 h before and after IHC, and nitric oxide synthesis was evaluated by 24-h urinary excretion of the stable nitric oxide metabolites nitrate and nitrite. IHC increased nitric oxide synthesis and decreased BP in hypertensive patients to values similar to those of normotensive individuals. Significant inverse correlations were found between nitric oxide production and disease duration, SBP, and DBP. Moreover, IHC enhancement of nitric oxide synthesis was especially robust in patients with arterial hypertension of more than 5 years duration. The reduction in BP persisted for at least 3 months in 28 of 33 hypertensive patients. IHC exerted a robust, persistent therapeutic effect and can be considered as an alternative, nonpharmacological treatment for patients with stage 1 arterial hypertension. The antihypertensive action of IHC is associated with normalization of nitric oxide production.