The Effects of Stimulus Area and Adaptation Temperature on Warm and Heat Pain Thresholds in Man

The effect of stimulus area and adaptation temperature on warm and heat pain thresholds were studied in healthy human subjects using a contact thermal stimulator. The stimulus area was varied in the range of 1.3 to 11.8 cm2. Both the warm and heat pain thresholds decreased with increasing stimulus surface. Heat pain and warm thresholds were equally affected by the stimulus surface. The adapting temperature was varied in the range 25-35°C, and warm thresholds were elevated with increasing adaptation temperature. The change of heat pain thresholds with increasing adapting temperature was not significant. Thus, there are both differences and similarities concerning how the different stimulus conditions affect heat pain and warm thresholds.