Four healthy adult males volunteered for this study, which followed informed-consent procedures administered by our local Human Use Committee. Esophageal (T(es)) and mean skin (T(sk), eight site) temperatures, forearm sweating rate (ṁ(s)), metabolism (M), heart rate (HR), and forearm blood flow (FBF) were measured at rest and during exercise [55% oxygen consumption (V̇O2) peak] during control experiments and after 2 mg im atropine (ATR). Experiments were randomized and separated by at least 72 h. ATR increased heart rate at rest by 15 beats/min and during exercise by 24 beats/min. ATR decreased whole body sweating by 57%. All eight local skin temperatures were higher in ATR than in control. T(sk) was 32.6°C in ATR and 31.0°C in control (P < 0.01). During exercise, ATR increased vasodilation of the forearm compared with control. The slope of FBF to T(es) increased over 300% in ATR experiments compared with control (P < 0.05). The higher sensible heat flux from this vasodilation decreased T(es) during exercise, which further decreased sweating. Skin blood flow remained elevated as T(es) ed, suggesting that local vasodilatory factors promoted atropine-induced cutaneous vasodilation.
|Journal||American Journal of Physiology - Regulatory Integrative and Comparative Physiology|
|State||Published - 1 Jan 1989|
- body temperature regulation