AUTHOR=Liu Boyan , Jiang Xue , Xie Yunbo , Jia Xiubin , Zhang Jiashuo , Xue Yazhuo , Qin Shucun 

TITLE=The effect of a low dose hydrogen-oxygen mixture inhalation in midlife/older adults with hypertension: A randomized, placebo-controlled trial

JOURNAL=Frontiers in Pharmacology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2022.1025487

DOI=10.3389/fphar.2022.1025487

ISSN=1663-9812

ABSTRACT=<p><bold>Objective:</bold> To explore the effect of a low-dose hydrogen–oxygen (H<sub>2</sub>-O<sub>2</sub>) mixture inhalation in midlife/older adults with hypertension.</p><p><bold>Methods:</bold> This randomized, placebo-controlled trial included 60 participants with hypertension aged 50–70 years who were randomly divided into Air group (inhaled placebo air) or H<sub>2</sub>-O<sub>2</sub> group [inhaled H<sub>2</sub>-O<sub>2</sub> mixture (66% H<sub>2</sub>/33% O<sub>2</sub>)]. Participants in both groups were treated 4 h per day for 2 weeks. Four-limb blood pressure and 24-h ambulatory blood pressure were monitored before and after the intervention, and levels of plasma hormones related to hypertension were determined.</p><p><bold>Results:</bold> A total of 56 patients completed the study (27 in the Air group and 29 in the H<sub>2</sub>-O<sub>2</sub> group). The right and left arm systolic blood pressure (SBP) were significantly decreased in H<sub>2</sub>-O<sub>2</sub> group compared with the baseline levels (151.9 ± 12.7 mmHg to 147.1 ± 12.0 mmHg, and 150.7 ± 13.3 mmHg to 145.7 ± 13.0 mmHg, respectively; all <italic>p</italic> &lt; 0.05). Meanwhile, the H<sub>2</sub>-O<sub>2</sub> intervention significantly decreased diastolic nighttime ambulatory blood pressure by 2.7 ± 6.5 mmHg (<italic>p</italic> &lt; 0.05). All blood pressures were unaffected in placebo group (all <italic>p</italic> &gt; 0.05). When stratified by age (aged 50–59 years <italic>versus</italic> aged 60–70 years), participants in the older H<sub>2</sub>-O<sub>2</sub> group showed a larger reduction in right arm SBP compared with that in the younger group (<italic>p</italic> &lt; 0.05). In addition, the angiotensin II, aldosterone, and cortisol levels as well as the aldosterone-to-renin ratio in plasma were significantly lower in H<sub>2</sub>-O<sub>2</sub> group compared with baseline (<italic>p</italic> &lt; 0.05). No significant differences were observed in the Air group before and after the intervention.</p><p><bold>Conclusion:</bold> Inhalation of a low-dose H<sub>2</sub>-O<sub>2</sub> mixture exerts a favorable effect on blood pressure, and reduces the plasma levels of hormones associated with hypertension on renin-angiotensin-aldosterone system and stress in midlife/older adults with hypertension.</p>