The Influence of Ethnicity on Thermoregulation After Acute Cold Exposure

摘要

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 a 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°C air).nnMethods.—Five AA males (20.8 ± 0.5 years) and 10 CAU males (25.6±4.9 years) underwent pre-experimental testing to determine VO2max (AA = 37.2 ± 0.1 mL·kg−1·min−1, CAU = 44.3 ± 8.7 mL·kg−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°C air (ACE) followed by 120 minutes of recovery in 25°C air (ACE-REC). Rectal temperature (Tre) was measured via a rectal thermistor. Mean skin temperature (Tsk) was assessed with thermistors. Oxygen consumption (VO2) was assessed via indirect open circuit spirometry. Rectal temperature and Tsk were measured continuously, and if Tre 35°C, testing was terminated.nnResults.—Analysis of variance for ACE-REC revealed a significant main effect for Tsk across time (P < .001), Tre across time (P < .001), and VO2 across time (P < .001). In addition, a significant time × ethnicity interaction was revealed for Tre (P = .008), Tsk (P = .042), and VO2 (P = .019) during ACE-REC.nnConclusions.—Based on these data, there is a differential response between CAU and AA across time for VO2, Tre, and Tsk ACE-REC.