Association Between Hydrogen-Rich Water Consumption and Lower Extremity Function in Older Adults Participating in Community Salons: A Prospective Observational Study

Abstract

Background: Falls among older adults are a leading cause of fractures, loss of independence, and need for long-term care. Community salons in Japan promote social participation and health activities among older adults. Hydrogen-rich water is widely used as a health product, but evidence in community settings remains limited. Methods: We conducted a prospective observational study among 48 community-dwelling older adults attending community salons in Hiroshima City, Japan. Hydrogen-rich water was offered by the salon operators as part of routine activities; the research team did not assign participants to consume it. Participants were categorized at baseline according to their usual hydrogen-rich water consumption at the salons (consumers vs non-consumers) and followed for six months. The primary outcome was the 30-second chair stand test (CS-30). Secondary outcomes included the Timed Up and Go test (TUG), usual gait speed, one-leg stance time, and grip strength. Within-group changes and between-group differences in change scores were compared. Results: All 48 participants completed follow-up, and no serious adverse events were reported during the study period. The consumers group showed a greater improvement in CS-30 over six months (baseline 12.96 (SD 3.21) to follow-up 14.52 (SD 3.59); change 1.57 (SD 2.41)) compared with the non-consumers group (12.52 (SD 3.00) to 12.22 (SD 3.54); change -0.30 (SD 1.55)), with a significant between-group difference in change scores (p=0.003). The consumers group also showed a greater increase in usual gait speed (0.91 (SD 0.24) to 0.98 (SD 0.26); change 0.07 (SD 0.08)) than the non-consumers group (0.94 (SD 0.24) to 0.97 (SD 0.22); change 0.03 (SD 0.05); p=0.008). No significant between-group differences were observed for TUG (p=0.57), one-leg stance time (p=0.13), or grip strength (p=0.10). Conclusion: In community-dwelling older adults participating in community salons, routine hydrogen-rich water consumption was associated with improved lower extremity function as measured by CS-30 and gait speed. Because exposure was not randomized, residual confounding cannot be excluded, and causal inference is limited. Larger studies with stronger designs are warranted. . CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted January 8, 2026. ; https://doi.org/10.64898/2026.01.07.26343642 doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.

Study details

Article type

Original Research

Disease / injury model

Fall risk / Lower extremity function in older adults

Duration

6 months

Dose-dependent effect

No

Outcome

Positive

Findings

Routine hydrogen-rich water consumption was associated with improved lower extremity function (CS-30 and gait speed) in community-dwelling older adults over six months, compared to non-consumers. No significant differences were observed for TUG, one-leg stance time, or grip strength. No serious adverse events were reported.