The Influence of Ethnicity on Thermoregulation After Acute Cold Exposure

Objective.-It is well established that a combination of factors, including ethnicity, may influence an individual's response to cold stress. Previous work from our laboratory has demonstrated that when faced with a cold challenge. there is a similar response in heat production between Caucasian (CAU) and African American (AA) individuals that is accompanied by it differential response in core temperature. The objective of this study was to evaluate the influence of ethnicity (CAU vs AA) on the thermoregulatory response after acute cold exposure (ACE-REC, 25 degrees C air). Methods.-Five AA males (20.8 +/- 0.5 years) and 10 CAU males (25.6 +/- 4.9 years) underwent pre-experimental testing to determine Vo(2max) (AA = 37.2 +/- 0.1 mL.kg(-1).min(-1). CAU = 44.3 +/- 8.7 mL.ka(-1)min(-1)) and body composition (AA = 14.6 +/- 5.4%, CAU = 19.2 +/- 5.0%). Participants underwent acute cold exposure that consisted of 120 minutes of exposure to 10 degrees C air (ACE) followed by 120 minutes of recovery in 25 degrees C air (ACE-REC). Rectal temperature T(re)) was measured via a rectal thermistor. Mean skin temperature (T(sk)) was assessed with thermistors. Oxygen consumption (Vo(2)) was assessed via indirect open circuit spirometry. Rectal temperature and T(sk) were measured continuously, and if T(re) <= 35 degrees C. testing was terminated. Results.-Analysis of variance for ACE-REC revealed a significant main effect for T(sk) across time (P < .001), T(re) across time (P < .001). and Vo(2) across time (P < .001). In addition, a significant time X ethnicity interaction was revealed for T(re) (P = .008). T(sk) (P = .042), and Vo(2), (P = .019) during ACE-REC. Conclusions.-Based on these data. there is a differential response between CAU and AA across time for Vo(2), T(re), and T(sk) ACE-REC.