Wearing a breathable T‐shirt does not affect thermoregulatory responses during exercise under hot conditions.

Sweat absorbed by clothing forms a moisture film on fabric surfaces, reducing fabric breathability and disrupting thermoregulation during exercise in a hot environment. We investigated whether T‐shirts made from a newly developed fabric with hydrophobic and water‐repellent fibers near the through holes could prevent sweat film formation, thereby enhancing intraclothing microclimate and thermoregulatory responses. Thirteen male runners completed 30‐min treadmill sessions at moderate and high intensities while wearing either the new fabric T‐shirt (Dry Aeroflow, DAF) or a polyester T‐shirt (CONT) at an ambient temperature of 32°C and a relative humidity of 50% with an air velocity of 0.8 m/s. Compared with CONT, intraclothing humidity was decreased on the chest and back, and chest but not back skin temperature was decreased by 2°C in DAF. However, thermoregulatory key variables such as rectal temperature, mean skin temperature, sweat rates, and heart rate did not differ between the T‐shirts. We concluded that the a T‐shirt with enhanced breathability does not affect overall thermoregulatory response during exercise in the heat despite the partial improvements in intraclothing microclimate and in reducing local skin temperature. [ABSTRACT FROM AUTHOR]