Molecular Hydrogen Positively Affects Physical and Respiratory Function in Acute Post-COVID-19 Patients: A New Perspective in Rehabilitation.
急性COVID-19後患者における分子状水素吸入が身体機能および呼吸機能に与える影響：リハビリテーションへの新たな視点
Abstract
A randomized, single-blind, placebo-controlled trial enrolled 50 acute post-COVID-19 patients (26 males aged 44±17 years; 24 females aged 38±12 years) who were symptomatic between 21 and 33 days after a positive PCR test. Participants underwent hydrogen gas or placebo inhalation twice daily for 60 minutes over 14 days. Outcomes included the 6-minute walk test (6MWT), forced vital capacity (FVC), and forced expiratory volume in one second (FEV1). Compared with placebo, hydrogen inhalation produced statistically significant improvements: 6MWT distance increased by 64±39 m, FVC by 0.19±0.24 L, and FEV1 by 0.11±0.28 L (all p≤0.025). These findings indicate that hydrogen gas inhalation may facilitate early restoration of physical and respiratory capacity in this patient population.
Mechanism
Molecular hydrogen is proposed to exert antioxidative, anti-inflammatory, anti-apoptotic, and antifatigue effects, thereby reducing oxidative stress and systemic inflammation associated with post-COVID-19 sequelae and supporting recovery of physical and pulmonary function.
Bibliographic
- Authors
- Botek M, Krejčí J, Valenta M, McKune A, Sládečková B, Konečný P, et al.
- Journal
- Int J Environ Res Public Health
- Year
- 2022 (2022-02-10)
- PMID
- 35206179
- DOI
- 10.3390/ijerph19041992
- PMC
- PMC8872486
Tags
Delivery context
In air, molecular hydrogen is reported to be combustible across approximately **4% (LFL, lower flammability limit) to 75% (UFL, upper flammability limit)**. Among high-concentration hydrogen inhalers, 66% output sits inside this range, and even pure-hydrogen (100%) output forms a 4–75% concentration-gradient layer at the device–air boundary (the UFL 75% paradox). Engineering principle would therefore call for operation below LFL (the classical 4%); that figure, however, was measured under closed, pre-mixed, static conditions. For the open, dynamic inhalation environment, the empirical value reported in the literature is **10%**, which is the figure referenced in practice as the operating ceiling. The 66% / 100% output devices are recorded in the Japanese Consumer Affairs Agency accident-information database, and from these considerations are not recommended.
Safety notes
See also: