Figure 2. Core and skin temperatures at the vasoconstriction and shivering thresholds were linearly related in men. The correlation coefficients averaged 0.90 plus/minus 0.06 for vasoconstriction and 0.94 plus/minus 0.07 for shivering. The extent to which mean skin temperature contributed to central thermoregulatory control (the proportionality constant beta) was calculated from the slopes (S) of the skin- temperature versus core-temperature regressions using the formula beta = S/(S - 1). Cutaneous contribution to vasoconstriction averaged 20 plus/minus 6%, which did not differ significantly from the contribution to shivering, which was 19 plus/minus 8%.