An experiment was conducted to investigate the effects of bathing in artificial CO₂ spa water (CO₂ 260ppm, at 38°C for 10 minutes) on the autonomic nervous system of man in comparison with those of bathing in plain water. The heart rate, coefficient of variation of R-R intervals of ECG (CV_RR), blood pressure, and pulse wave were measured, and dynamic autonomic nervous function tests as described by Nishijo et al. were performed on eight gealthy volunteers (female).
The results obtained showed that the heart rate and height of pulse wave increased and blood pressure decreased during bathing both in artificial CO₂ spa water and plain water. However, the systolic blood pressure increased after bathing in plain water but did not increase after bathing in artificial CO₂ spa water. Though CV_RR decreased during and after bathing in plain water, it did not decrease after bathing in artificial CO₂ spa water. Furthermore, the related degree of sympathetic and parasympathetic nervous functions increased after bathing in artificial CO₂ spa water (as measured after 40 minutes and 50 minutes). These results suggest that bathing in artificial CO₂ spa water can enhance the functions of the autonomic nervous system.

This study was a nonrandomized controlled trial, aimed to identify the effects of a walking program designed to improve the physical functions of elderly people requiring support or low-level care and receiving rehabilitation services at day care centers. Participants were 28 elderly people (mean age: 77.9±7.5 years). Twelve participants agreed to wear a physical activity monitoring device. Their daily walking goals were updated every week. Sixteen subjects designated as a control group only underwent personalized rehabilitation programs. The gait functions of all subjects were evaluated by several gait parameters before and after the 4-week intervention. ADL and QOL were assessed using the Tokyo Metropolitan Institute Gerontology Index of Competence and 8-Item Short-Form Health Survey (SF-8), respectively. The step length, walking angle, the stance phase ratio and the double-support phase ratio significantly improved in the intervention group after the walking program. Interaction effects of the stance phase ratio, the double-support phase ratio and QOL (mental component summery) were observed between the two groups. The walking program, combined with rehabilitation services, showed favorable effects on the gait functions, and QOL of elderly people, suggesting that it may be useful for preventing functional deterioration of the elderly requiring support or low-level care.