Hemodynamic responses to cold stress in blacks: effect of application site

Black Americans have been shown to exhibit increased blood pressure responses to a variety of physical stressors. However, few investigators have examined hemodynamic responses to cold stress. Additionally, no studies have compared blood pressure responses to forehead and foot stress in blacks. Therefore, in this study, hemodynamic responses to cold pressor tests were compared in 30 blacks (15 males, 15 females) utilizing two application sites. Baseline comparisons of systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), forearm blood flow (FBF) and forearm vascular resistance (FVR) were not different prior to forehead and foot cold stress. Following baseline measurements, ice was applied separately to the forehead and foot for 90 seconds with hemodynamic measurements being recorded at 45 and 90 seconds. During application of ice to the forehead, FVR-90 was significantly higher (P < .002, 97.0 units vs. 66.4 units) compared to the foot. The application of ice to the foot resulted in significantly greater SBP-45 responses (P < .0001, 147 mmHg vs. 139 mmHg), HR-45 responses (P < .0043, 80, b.min-1 vs. 69 b.min-1). HR-90 responses (P < .0001, 78 b.min-1 vs. 64 b.min-1), and FBF-45 responses (P < .05, 2.74 ml.min-1.100ml-1 vs. 1.98 ml.min-1.100ml-1). These findings suggest that blacks exhibit disparate patterns of reactivity in response to cold stress as a function of application site. Therefore, investigators should consider the application site when interpreting studies examining a biracial cohort.