| Keywords |
Capillary diameter ; Temperature stimulation ; Blood pressure ; Clothing microclimate ; Thermoregulatory response |
| Abstract |
This study was conducted to investigate effects of thermal stimulation using an air temperature on hemodynamic responses including capillary diameters and relationship between hemodynamic and thermoregulatory responses. 22 male subjects participated under two experimental conditions: cold exposure (CE, 10.5±0.8oC) and heat exposure (HE, 40.9±0.4oC). Both arterial and venous diameters in CE were smaller than those in HE and flow velocity was 3 times faster in HE compared to CE (p<.001). Participants felt more uncomfortable and more intolerable in HE compared to CE (p<.05). The smaller venous diameter was, the higher blood pressures were, and venous diameter and flow velocity had positive relationships with microclimate temperature (p<.01) and skin and rectal temperatures (p<.05). Thermal sensation had positive relationships with venous diameter and flow velocity, while it had negative relationships with blood pressures (p<.01). These results indicate that vasoconstriction or vasodilatation can be measured directly and visually by using the capillaroscopy and hemodynamic responses including sizes of capillary have relationships with thermoregulatory responses. |