Effects Of Polyester Wicking Versus Cotton Fabric T-shirt On Sweat Rate In Obese Males

The effects of different t-shirt fabrics on thermoregulation during exercise remain to be elucidated. PURPOSE: This crossover study investigated the effects of cotton (C) versus polyester (P) t-shirts on sweat rate and skin temperature at the torso (chest, back) and peripheral (forearm, forehead) regions of physically active, obese males. METHODS: Seven participants (21.7 ± 1.7 yr; 35.7 ± 6.7 kg·m-2) completed 4 visits (separated by 48 hrs); visit 1 was to complete the informed consent, ACSM health questionnaire, PAR-Q, and body composition assessment using air displacement plethysmography. Visit 2 was a VO2max test (30-sec averaging for expired gas analysis), followed by two treadmill walking sessions (30 min at 30 - 39% VO2reserve) in either C or P t-shirt (randomized, counterbalanced sequence) on the third and fourth visits. Exercise was performed in a hot and dry (27 C°, 10 ± 2% relative humidity) environment. Sweat rate was determined as ∆ nude body weight (pre- minus post-exercise body weight) using a digital scale. Skin temperature was measured during exercise using a skin thermometer. Torso skin temperature (Tsktorso) was the sum of 0.5TChest + 0.5TBack. Peripheral site skin temperatures were analyzed separately. A dependent t-test was used to compare sweat rates. Separate two-way ANOVAs were performed to investigate fabric type, time, and their interactions on skin temperature by body region. RESULTS: On average, participants’ VO2max and body fat were 36.8 ± 8.7 mL·kg-1·min-1 and 34.7 ± 4.3%, respectively. There was no difference between C and P conditions in sweat rates (∆ body weight = -.35 ± .11 kg; -.37 ± .20 kg, respectively, p = .754). A significant interaction effect was detected between Tsktorso and fabric (p = .022) with C > P. Interaction effects of skin temperature in the peripheral regions (forearm, p = .195; forehead, p = .057) were nonsignificant. CONCLUSION: Though the sweat rate was similar across cotton and polyester trials, polyester appears to be effective for temperature regulation, especially in the torso region during low intensity aerobic exercises in young, obese males. Future research should explore the impact of C vs. P fabric on sweat rate and skin temperature during different intensities and modalities of exercise.