Hydrogen Water Baths Keep Your Body Warmer Longer Than Regular Baths
- Authors
- Shinya Kato, Yuki Takada, Nobuhiko Miwa
- Journal
- Journal of Thermal Biology
- Year
- 2021
- DOI
- 10.1016/j.jtherbio.2020.102805
- Study Type
- Human
- Outcome
- Positive
- Peer Reviewed
- Yes
- Country
- Japan
- Health Condition
- Poor Circulation
- Body System
- Cardiovascular
TL;DR
Taking a bath in hydrogen-rich water seems to keep certain parts of the body warmer for longer and may improve blood flow better than a regular bath.
Key Finding
Hydrogen-rich water baths produced greater heat retention in the abdomen, upper legs, arms, and hands for up to 60 minutes after bathing compared to regular water baths, with evidence suggesting improved blood circulation as a potential mechanism.
Summary
Researchers used thermal imaging cameras to measure how well heat stays in the body after bathing in hydrogen-rich water versus regular water. In 24 healthy people, hydrogen-rich water baths (at 41°C for 10 minutes) kept the abdomen, upper legs, arms, and hands warmer for 30-60 minutes after bathing compared to regular water baths. The study also found that blood vessels in fingertips expanded more after hydrogen-rich water bathing, suggesting the effect may involve improved blood circulation rather than just better insulation.
Practical Takeaway
This small study suggests hydrogen-rich water bathing may help retain body heat longer than regular bathing, possibly through effects on blood flow. However, the study involved only 24 people and measured thermal effects immediately after bathing—longer-term health benefits remain unclear. More research is needed to determine whether these heat-retention effects translate to meaningful health outcomes.
Abstract
Hydrogen-rich water bath devices are commercially available, but have been scarcely clarified for heat-retention effects. In this study, heat-retention effects of hydrogen-rich water bath were assessed by thermographic clinical trials, which employed twenty-four healthy subjects. The thermograms indicated that, under the same conditions (41 °C, 10-min bathing), hydrogen-rich water bath (hydrogen concentrations: 185-548 μg/L; oxidation-reduction potentials: -167 to -91 mV, versus 0.8 μg/L and +479 mV for normal bath, respectively) brought about the heat-retention being more marked than those of normal water bath for several body-parts in the order as follows: abdomen > upper legs > arms > hands > feet, for 30- and 60-min post-bathing, being in contrast to scarce heat-retention for head, armpits and lower legs. Then, as reflection to promotive effects on blood stream, we also examined the thickness of fingertip-capillary in hands. The thickness was expanded in the hydrogen-rich water bath more markedly than that in the normal water bath, suggesting that the hydrogen-rich water bath may have the hydrogen-based promotive effect, exceeding over mere heat retention-based effects, on blood circulation of the whole body. Meanwhile, the heat-retention in hydrogen-rich water bath weakly or moderately correlated with contents of the subcutaneous fat, whole body fat and body mass index, and inversely correlated with skeletal muscle rates, although their correlation degrees did not obviously exceed over normal water bath, with a poor relation with the basal metabolism rate. Thus, the hydrogen-rich water bath was suggested to exert heat-retention effects exceeding over normal water bath, in diverse body-parts such as abdomen, upper legs, arms and hands, via promotion to blood flow which was reflected by expanding the thickness of capillary. The heat-retention after bathing can be noted as effects of the hydrogen-rich water bath, which is applicable for most of people widespread regardless of their body composition index.