Glabrous and non-glabrous vascular responses to mild hypothermia

Abstract This study examined cutaneous vasoconstriction to whole-body hypothermia, specifically contributions of neural and endothelial vasomotor responses in glabrous and non-glabrous skin. Eleven participants were semi-recumbent at an ambient temperature of 22 °C for 30 min, after which ambient temperature was decreased to 0 °C until rectal temperature ( T re ) had decreased by 0.5 °C. Laser-Doppler fluxmetry was measured at the forehead and thigh for measures of glabrous and non-glabrous skin, respectively; wavelet analysis was performed on the laser-Doppler signal to determine endothelial and neural activities. Hypothermia took on average 97 ± 7 min and caused marked decreases at glabrous (42 ± 5%baseline, p p p p  = 0.001) in neural activity from 13 ± 2% to 9 ± 1% (−0.2 °C decrease in T re ) and then increased ( p  = 0.002) to 21 ± 2% baseline at −0.5 °C T re . Endothelial activity decreased in both glabrous (16 ± 3% to 6 ± 1%, p p  = 0.003) skin. Hypothermia elicits large decreases in skin blood flow in both glabrous and non-glabrous skin that are related to increases in neural activity and a reduction of endothelial activity.