title: Caffeine increases sweating sensitivity via changes in sudomotor activity during physical loading.
abstract: We assessed the effect of caffeine on sudomotor activity and sweating sensitivity during physical loading. Both physiological responses could occur due to energy expenditure. Subjects were 13 athletically trained males (22.1 ± 3.7 years old, 174.2 ± 5.4 cm tall, and weighing 70.9 ± 4.6 kg, with maximal oxygen consumption [VO(2)max] of 53.6 ± 4.4 mL/kg/minute). The study involved a within-subject, random, crossover design. Tests were performed following the ingestion of 3 mg/kg caffeine. The physical loading involved running for 30 minutes at 60% VO(2)max (24.0 ± 0.5°C, 40 ± 3.0% relative humidity). Tympanic temperature (TYMP) was significantly higher in the caffeine-consuming group (Caffe-I) at pre-exercise (40 minutes after caffeine intake and immediately before running) (P<.05). Mean body temperature (mT(b)) was significantly higher in the Caffe-I group at pre- and post-exercise (30 min after start of running) (P<.05). Onset time of localized sweating was significantly shorter in the Caffe-I group (P<.01), but localized sweat volume and active sweat gland output (per single gland) was significantly higher in the Caffe-I group (P<.001). Activated sweat gland density was significantly increased in the Caffe-I group on the abdomen and thigh (P<.01). In conclusion, caffeine ingestion caused not only increases in TYMP and mT(b) through thermogenesis, but also an increased sweating sensitivity via changes in sudomotor activity.
authors: Department of Health Care, Graduate School, Soonchunhyang University, Asan, Korea.
authors: Tae-Wook
authors: TW
authors: Kim
authors: Young-Oh
authors: YO
authors: Shin
authors: Jeong-Beom
authors: JB
authors: Lee
authors: Young-Ki
authors: YK
authors: Min
authors: Hun-Mo
authors: HM
authors: Yang
mesh_terms: D000328:Adult; D001833:Body Temperature Regulation; D002110:Caffeine / Q000494:pharmacology*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004734:Energy Metabolism; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D010101:Oxygen Consumption; D005082:Physical Exertion / Q000187:drug effects*; D013545:Sweat Glands; D013546:Sweating / Q000187:drug effects*; D055815:Young Adult
chemical_list: D002110:Caffeine