Individuals of black African (BA) descent display a diminished vascular response to various stimuli compared with individuals of white European (WE) descent. Whether the glabrous peripheral microcirculatory responses differ between these racial groups is unknown. We hypothesised that the vascular responses to local heating (LH) and post-occlusive reactive hyperaemia (PORH) would be impaired in the index finger and Great toe pad of BA individuals compared with WE individuals.

Following Loughborough University ethical approval and written informed consent, ten WE (mean [SD] age 25 [4] years, height 1.75 [0.09] m, mass 72.0 [13.0] kg) and eight BA (age 20 [2] years, height 1.72 [0.11] m, mass 81.3 [14.3] kg) participants undertook PORH and LH protocols in 25 °C ambient air. Cutaneous vascular conductance (CVC; flux/mean arterial pressure) was measured at the finger and toe pad with local skin temperature clamped at 33 °C. PORH protocol: following a 10 min baseline, finger and toe blood flow was occluded (220 mmHg) for 5 min and then rapidly released. The area of hyperaemia (area under the curve [AUC]) was calculated above the baseline using the trapezoid rule. LH protocol: local skin temperature was clamped at 33 °C for 10 min followed by 42 °C for 20 min and then 44 °C for 10 min. Plateau averages at 42 °C and 44 °C were taken from stable 5 min periods. PORH variables were analysed using independent samples t-tests whilst LH was analysed using a mixed model ANOVA.

Table 1. Mean (SD) area under the curve and cutaneous vascular conductance during each protocol for WE and BA groups

Vascular responses of the finger and toe pad were similar in WE and BA participants for each protocol (Table 1, P>0.05), thus the hypothesis is rejected. From the present data, it appears the diminished vascular response previously reported in BA individuals is not present in the glabrous peripheral skin sites.