This study examined the effect of hot-spring bathing (40 to 41°C) on salivary secretion and salivary secretory IgA (sIgA) in healthy volunteers. Ten volunteers (10 men, average 33.6±9.3 years old) bathed in a hot-spring for 10 minutes.
Saliva samples were collected before bathing, during bathing (from 5 to 7 min), and after bathing using the Saxon test. The saliva flow rates and sIgA concentration were determined and then the sIgA secretion rates were calculated.
The saliva flow rates increased significantly during the bathing (p<0.02) and decreased after bathing. The sIgA secretion rates during bathing were significantly higher than those before and after bathing (p<0.02).
The increases in saliva flow rates and sIgA secretion rates during bathing were considered to indicate the improvement of local immunity in the oral cavity and thus considered to be useful for preventing upper respiratory tract infections.
