Consistency of hemodynamic responses to cold stress in adolescents.

Laboratory research on hypertension often is performed with cold stress to elicit vasoconstriction and increases in blood pressure. Several studies have shown that cardiovascular responses to the cold pressor test predict the development of hypertension. We extended this research by comparing cardiovascular responses to a traditional forehead cold pressor test and a naturalistic whole-body cold exposure. We evaluated blood pressure and impedance cardiographic measures of cardiac output and total peripheral resistance in healthy black (n=69) and white (n=47) adolescents (mean age, 14.7 years) during forehead cold pressor (3 degrees C to 4 degrees C) and passive whole-body exposure to a cold chamber (8 degrees C to 10 degrees C). Both tasks elicited increases in vascular resistance and blood pressure, but forehead cold elicited an increase in cardiac output, whereas whole-body cold elicited a decrease in cardiac output (P<0.05). Consistent with previous research, there was a tendency toward greater vasoconstrictive reactivity to cold stress in blacks than in whites, particularly during whole-body cold exposure (P<0.05). Cardiovascular reactivity correlated significantly between tasks, but substantial intertask consistency occurred only for cardiac and vascular reactivity in male subjects (r>0.30) but not in female subjects (r<0.15). These gender differences might reflect diminished adrenergic receptor function in female subjects. We conclude that whole-body cold exposure offers a viable, relatively naturalistic alternative to traditional cold pressor tests for the assessment of cardiovascular reactivity.