Cold pressor indices.

<p>A: heart rate increase from baseline to initial peak (i); B: sustained heart rate elevation during mid-challenge period (area-under curve, ii); C: rate of change (slope) during mid-challenge increase (iii). Time trend graph illustrates the mean heart rate of the 57 subjects in the control group, with a simplified representation (thick black line) overlaid on the measured values (gray line). Shaded area indicates challenge period.