Figure 1. The effect of increasing propofol blood concentration on the core temperatures triggering sweating (open circles and thin line), vasoconstriction (filled circles and medium line), and shivering (open triangles and thick line) in five volunteers. Propofol, up to 8 micro gram/ml blood concentration, linearly reduced the vasoconstriction and shivering thresholds by 0.6 plus/minus 0.1 and 0.7 plus/minus 0.1 degree Celsius *symbol* micro gram sup -1 *symbol* ml sup -1, respectively. The sweating threshold, however, increased only slightly (0.1 plus/minus 0.1 degree Celsius *symbol* micro gram sup -1 *symbol* ml sup -1). All the thresholds (at a designated skin temperature of 35.7 degrees Celsius) were calculated from measured skin and core temperatures.