Effects of CO2 bathing on local sweat rate, core and skin temperatures and cutaneous blood flow

Abstract

The purpose of our study is to investigate the effect of CO2 (100 ppm) bathing on local sweat rate, core and skin temperatures, and local cutaneous blood flow. Ten healthy students participated in this study. Each subject underwent fresh water bathing and CO2 water bathing on different days. The subject was immersed in a bath at a water temperature of 40°C for 10 min up to the nipple level after a rest of 20 min at 30°C (40%RH), and had a rest again for 30 min. Tympanic and skin temperatures and sweat rate and cutaneous blood flow in the non-immersed area of upper chest were measured continuously. The results were: (1) chest blood flow was significantly greater during the CO2 bathing than during the fresh water bathing, (2) chest sweat rate was significantly greater during the CO2 bathing than during the fresh water bathing, (3) the increase of tympanic temperature was significantly greater during the CO2 bathing than during fresh water bathing, and (4) skin temperature in the chest was not different between the CO2 water bathing and the fresh water bathing. We concluded that CO2 bathing at 100ppm affects thermoregulatory responses through the mechanism of cutaneous vasodilatation. [Jpn J Physiol 54 Suppl:S228 (2004)]