The thermotherapeutic effects of bathing with CO₂ water obtained from a newly developed CO₂ water supply system was studied in comparison with bathing with plain water. After 10min bathing at 39°C, dermal blood flow in the upper arm region was higher in the group bathing with CO₂ water than in that bathing with plain water (p<0.05).
Further, the skin temperature lowering in the forehead region after bathing was slower in the group bathing with CO₂ water than in that bathing with plain water. The subjective sense of being heated and sense of comfort during and after bathing were also higher in the group bathing with CO₂ water. No side effects were found. It is therefore suggested that the CO₂ water obtained from this system is useful for enhancing the thermotherapeutic effect of bathing.