Hydrogen Gas Helps Heart Attack Survivors Reduce Harmful Stress
Hydrogen gas inhalation alleviates oxidative stress in patients with post-cardiac arrest syndrome
Research hubs: Cardiovascular System · Respiratory System
- Evidence type
- Case report or series · Human study
- Authors
- Tomoyoshi Tamura, Masaru Suzuki, Kei Hayashida, Yosuke Kobayashi, Joe Yoshizawa, Takayuki Shibusawa, Motoaki Sano, Shingo Hori, Junichi Sasaki
- Journal
- Journal of Clinical Biochemistry and Nutrition
- Year
- 2020
- PMID
- 33041520
- Study Type
- Human
- Participants
- 5
- Delivery
- Gas
- Dose
- 2% hydrogen with titrated oxygen for 18 hours
- H₂ concentration
- 2% H2 gas
- Duration
- 1 day or less
- Conflicts of interest
- SH, TT, MSuzuki, KH, and MSano received research funding from Taiyo Nippon Sanso Corporation (no identifiable number). The other authors state no disclosures.
- Outcome
- Positive
- Peer Reviewed
- Yes
- Cited by
- 32 (OpenAlex, as of November 2026)
- Country
- Japan
TL;DR
Breathing in hydrogen gas may reduce cell damage from oxygen-related stress in patients who are unconscious after a heart attack, but its overall effects are still uncertain.
Key Finding
Hydrogen gas inhalation produced measurable levels in the blood and showed different effects depending on the cause of cardiac arrest: reducing oxidative stress markers in heart-related cases but reducing inflammatory markers in the infection-related case.
Summary
This small study looked at whether breathing hydrogen gas could help five patients who were unconscious after their hearts stopped beating. Researchers measured markers of cellular damage (oxidative stress) and inflammation in the patients' blood before and after 18 hours of inhaling hydrogen gas mixed with oxygen. In patients whose cardiac arrest was caused by heart problems, hydrogen appeared to reduce cellular damage, but it didn't change inflammation levels. In one patient whose cardiac arrest was caused by infection, the opposite occurred—inflammation decreased but cellular damage didn't change. The researchers noted that the study was too small and had other limitations that prevent clear conclusions.
Practical Takeaway
While this early human study suggests hydrogen gas may reach the bloodstream and have some biological effects in post-cardiac arrest patients, the very small sample size (five patients) and acknowledged methodological weaknesses mean these results are preliminary. Much larger, well-designed studies are needed before any conclusions can be drawn about whether hydrogen gas could help cardiac arrest patients in clinical practice.
Abstract (excerpt)
Oxidative stress plays a key role in the pathophysiology of post-cardiac arrest syndrome. Molecular hydrogen reduces oxidative stress and exerts anti-inflammatory effects in an animal model of cardiac arrest. However, its effect on human post-cardiac arrest syndrome is unclear. We consecutively…