Consistency of Hemodynamic Responses to Cold Stress in Adolescents

Abstract

Abstract-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 (nϭ69) and white (nϭ47) adolescents (mean age, 14.7 years) during forehead cold pressor (3°C to 4°C) and passive whole-body exposure to a cold chamber (8°C to 10°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 (PϽ0.05). 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 (PϽ0.05). Cardiovascular reactivity correlated significantly between tasks, but substantial intertask consistency occurred only for cardiac and vascular reactivity in male subjects (rϾ0.30) but not in female subjects (rϽ0.15). 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. (Hypertension. 2000;36:1013-1017.)Key Words: stress Ⅲ vasoconstriction Ⅲ cardiac output Ⅲ blood pressure Ⅲ hemodynamics Ⅲ adolescents C old stress is often used to elicit ␣-adrenergic vasoconstriction and pressor responses (ie, blood pressure [BP] increases) in laboratory research on hypertension. [1][2][3][4][5] The most commonly used cold stressor is some variation of the cold pressor test, which involves the immersion of a limb in ice water or the placement of a bag of ice water on the forehead. 1,4 -9 A number of studies have shown that cardiovascular responses to the cold pressor test predict future resting BP and the development of hypertension. 10 -12 Furthermore, studies of both adults and children indicate that blacks, who are at increased risk for early hypertension development, 13,14 exhibit greater vascular reactivity during limb and forehead cold pressor tasks relative to whites. [15][16][17][18][19][20][21] Traditional laboratory cold pressor tasks typically involve limited regional body surface exposure to very cold and often painful ice water slurries (Ϸ4°C), 6 -9 so it is not clear whether the cardiovascular effects of such tasks can be generalized to more naturalistic environmental cold exposure (CE). However, in a recent study of adolescents, 3 we demonstrated that whole-body CE (8°C to 10°C) elicited increases in total peripheral vascular resistance and BP similar to those elicited by traditional cold pressor tasks a...

Wave reflection augments central systolic and pulse pressures during facial cooling

“…We could not calculate vascular resistance since we did not measure cardiac output; however, we did not observe any change in heart rate, and it was previously reported that facial cooling does not alter cardiac output (25,36). Therefore, the rise in MAP would indicate that smooth muscle tone increased in resistance vessels as a result of facial cooling.…”

Juvenile onset depression alters cardiac autonomic balance in response to psychological and physical challenges

“…This task elicits a reduction in parasympathetic activity (RSA withdrawal), which may also occur in combination with increased sympathetic activity (e.g., Miller, 1994; Freyschuss, 1970; Martin et al, 1974, Nutter, Schlant & Hurst, 1972, Pollak & Obrist, 1988) and has been used successfully in our age group (e.g., Matthews, Woodall, & Stoney, 1990; Kelsey, Patterson, Barnard, Alpert, 2000). …”

Reliability of cardiovascular reactivity to stress: Internal consistency

“…Study 2 included 136 healthy adolescents ( n =72 females, n =64 males; age, M ± SD =14.7±1.5 years) recruited from the Memphis, Tennessee, area for a research project on early markers of hypertension (see Kelsey, Alpert, Patterson, & Barnard, 2000; Kelsey, Patterson, Barnard, & Alpert, 2000). The sample included 78 Black participants (57.4%) and 58 White participants (42.6%).…”

“…In all three studies, these signals were recorded from a tetrapolar aluminum/mylar disposable tape electrode system placed in accordance with established guidelines (Sherwood, Allen, et al, 1990). An electrocardiographic (ECG) signal was recorded from the outer pair of impedance electrodes in Studies 1 and 3 (Kelsey et al, 1999, 2004; Kelsey, Blascovich, et al, 2000) and from disposable spot electrodes placed on the torso in a modified Lead I configuration in Study 2 (Kelsey, Alpert, et al, 2000; Kelsey, Patterson, et al, 2000).…”