Center for the Built Environment

The ability of human hands and feet to convey skin thermal sensations is an important contributor to our experience of the surrounding world. Surprisingly, the detailed topographical distribution of warm and cold thermosensitivity across hands and feet has not been mapped, although such sensitivity maps exist for touch and pain. Using a recently developed quantitative sensory test, we mapped warm and cold thermosensitivity of 103 skin sites over glabrous and hairy skin of handsand feet in male (30.2±5.8y) and female (27.7±5.1y) adults matched for body surface area (M 1.77±0.2m2; F 1.64±0.1m2; p=0.155). Our findings indicated that warm and cold thermosensitivity varies by 5-fold across glabrous and hairy skin of hands and feet, and that hands are twice as sensitive as the feet. Opposite to what is known for touch and pain sensitivity, we observed a characteristic distal-to-proximal increase in thermosensitivity over both hairy and glabrous skin (i.e. from fingers/toes to body of hands and feet), and found that hairy skin is more sensitive than glabrous. Finally, we show that body-surface-area-matched males and females presented small differences in thermosensitivity, and that these differences are constrained to glabrous skin only. Our high-density thermosensory micromapping provides the most detailed thermosensitivity maps of hands and feet in healthy young adults available to date. These maps provide a window into the peripheral and central mechanisms of thermosensory integration in humans, and will help in guiding future developments in smart skin and sensory neuroprostheses, in wearable energy-efficient personal comfort systems, and in sport and protective clothing.