| Keywords |
Caffeine ; Onset time of sweating ; Activated sweat gland density ; Sweat sensitivity ; Sympathetic nervous system |
| Abstract |
Remaining unclear is the contribution of caffeine ingestion in sweating sensitivity. This study investigated the effects of caffeine ingestion on onset time of local sweating (OTLS) and mean activated sweat gland density (MASGD). Ten trained male subjects (age, 21.0 ± 2.5 years; height, 173.0 ± 3.2 cm; weight, 72.5 ± 4.3 kg and VO2max, 54.3 ± 3.5 ml/kg/min) exercised on a treadmill at an intensity of 60% of maximal oxygen consumption. Subjects exercised once after 3 mg/kg caffeine ingestion and once after no caffeine, given in a random and crossover design. Following caffeine ingestion significant shorter OTLS than no caffeine on chest (P < 0.01), abdomen (P < 0.001), back (P < 0.01), thigh (P < 0.01). And M-ASGD more higher following caffeine ingestion than no caffeine at 10 min (P < 0.001) and 15 min (p < 0.001). Thus, under the conditions of this study, the sweating sensitivity (shorter OTLS and higher M-ASGD) increased by stimulating sympathetic nervous system and the sweat glands increased their cholinergic sensitivity following caffeine ingestion. However, the effect of caffeine on sweating sensitivity was not continuously for long time during physical activity and may expected within the early 15 minutes of physical activity. |