HEMODYNAMIC RESPONSES TO COLD STRESS APPLIED TO THE FOREHEAD AND FOOT IN BLACKS 1059

Abstract

Black Americans have been shown to have increased blood pressure responses to a variety of stressors. However, inconsistent data have been reported during cold stress. Therefore, in this study hemodynamic responses to cold pressor tests were measured in 15 blacks utilizing two sites. The forehead site has been shown to elicits an alpha-adrenergic response while the application of ice to the foot elicits a beta-adrenergic response. Baseline comparisons of systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), casual forearm blood flow (CFBF) and forearm vascular resistance (FVR) were not different prior to forehead and foot cold stress. Following baseline measurements, ice was applied utilizing a counter-balanced design for 90 seconds with hemodynamic measurements being recorded at 45 and 90 seconds. HR-90 was significantly higher during the application of ice to the foot 66 ± 4.4 vs. 59 ± 2.8. During application of ice to the forehead, DBP-90 and FVR-90 were significantly higher 99 ± 2.8 vs. 88± 3.6, 63 ± 10.0 vs. 48 ± 6.7, respectively. These findings suggest that blacks exhibit an increased blood pressure responsiveness during application of cold to the forehead as a result of an elevation in peripheral resistance. Therefore, careful consideration needs to be given as to the site of the cold stress when interpreting investigations examining a biracial cohort.