Physiological evaluation of clothing made of new material for protection against the solar heat load

The purpose of this study was to evaluate the effects of clothing made of a new material that is, the polyester staple containing the ceramics and to reflect the solar heat load on physiological responses during rest, exercise (50% VO2max) and recovery on a cycle ergometer. Six young female subjects exposed their back to an artificial solar heat load of an intensity of 680 kcal/m2/h with an air temperature of 30 degrees C. The data were compared to those obtained by wearing clothing made of cotton material. The results were as follows. The cardiac output and oxygen consumption obtained at the end of recovery were increased by solar heat load when the subjects wore cotton material. However, these values showed no significant increase when the subjects wore solar heat reflecting clothing. Furthermore, the cardiac output at the end of submaximal work and recovery were higher for the cotton material compared to the heat reflecting clothing in the solar heat load. The increase of cardiac output for the cotton material may show the increase of skin blood flow for the body heat dissipation. Those results suggest that the solar heat reflecting clothing may decrease the physiological strain like a blood redistribution for the body heat dissipation during exercise in summer sunlight.