Whole-body heating decreases central venous pressure (CVP) and presumably cardiopulmonary baroreceptor loading in humans. We sought to identify whether this occurrence attenuates the elevation in skin blood flow (SkBF) during a hyperthermic challenge. Four subjects were exposed to indirect whole-body heating while SkBF (laser-Doppler flowmetry), CVP, mean arterial pressure (MAP), and esophageal temperature (Tes) were monitored. Cutaneous vascular conductance (CVC) was indexed from the ratio of SkBF to MAP. At peak heat stress, 15 ml·kg-1 warmed saline was infused intravenously to return CVP to pre-heat stress levels. Rates of elevation in CVC and Tes were calculated 5 min prior to, and 5 min during, saline infusion using linear regression on data sampled at 1 Hz. Rate of CVC elevation (CVC units·min-1) Rate of Tes elevation °C·min-1) CVP (mmHg) MAP (mmHg) Pre-HS - - 7.8±0.9 89±6 Peak-HS 0.9±0.1 0.023±0.009 4.9±0.6a 73±7a Saline 3.2±0.6* 0.019±0.008 8.0±0.7* 69±8a HS: heat stress, 1: Significantly different from pre-HS period (P<0.05). *: Significantly different from peak-HS period (P<0.05). Data are expressed as mean±SEM. Significant increases in the rate of elevation in CVC following the return of CVP to pre-heat stress levels, coupled with a lack of change in the rate of Tes elevation, suggest unloading of the cardiopulmonary baroreceptor coincident with hyperthermia attenuates the elevation in SkBF.
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology