This pilot study demonstrates that a single session of whole-body bathing in supersaturated HRW reduces muscular damage and can ease sore muscles after high-intensity eccentric exercise in young men. HRW appears to be superior to control water whole-body bathing in attenuating the exercise-driven rise in serum CK, implying less local muscular strain and fast-track recovery from soreness when the intervention was administered immediately after exercise. HRW bathing also provokes no major side effects and might, therefore, be put forward as a safe and convenient promising therapeutic modality in sports medicine.
Although often proclaimed as an effective post-exercise recovery procedure, the use of whole-body hydrogen bathing is rather rarely scrutinized in scientific studies. In a pioneering placebo-controlled trial, a Japanese group evaluated the effects of 20-minute hydrogen immersion on biomarkers of oxidative stress and DOMS in active young men who performed downhill running for 30 min . The authors found no effects of repeated hydrogen baths on oxidative stress and muscle damage indicators, although VAS scores for DOMS were reduced at 1 and 2 days after an exercise session. Another trial by the same group found no effects of HRW bathing (20 minutes per day for 7 days) on inflammatory markers (including neutrophil dynamics and function) in active men subjected to eccentric exercise . Our study confirmed that hydrogen bath improves VAS scores, yet using supersaturated HRW appeared to effectively prevent any rise in DOMS biomarkers after exhaustive leg press exercise. A longer immersion protocol (30 min) and highly concentrated HRW (8 mg/L) employed in our study perhaps facilitates recovery potential of supersaturated HRW, allowing for the lower-grade release of CK from damaged muscles to the circulation and/or enhanced clearance of CK from the blood, as compared to the control bath. The previous studies suggested that HRW baths did not affect oxidative stress biomarkers  and cytokine responses , suggesting another possible mechanism(s) that could drive favorable effects of HRW on muscle soreness. Hydrogen could affect gene expression , but this effect perhaps appears in slow dynamics, while HRW bathing manifests biological effects comparatively rapidly. Hypothetically, HRW bathing could maintain sarcolemma intact (or less permeable) to enzyme leakage by stabilizing muscle cell viability via acute modulation of central nuclei-related mechanisms . This possibility should be explored in forthcoming studies.