Changes in Cold/Warm Thresholds with Advancing Age -The Case of Adult Women Aged from the 20s to the 80s-

The purpose of this study is to investigate the changes in cold/warm thresholds of women with advancing age. Tamura et al. have developed a new device for measuring the cold/warm thresholds as a method of evaluating sensitivity of the human skin. By using the device, changes in the cold/warm thresholds in adult women were investigated. Sixty-eight healthy female subjects aged 20 to 88 years old wearing only under pants and brassiere lay in a supine position on a saran bed and their cold/warm thresholds were measured over 26 body regions under the condition of 28°C ambient temperature and 50%RH. The results showed that the cold/warm thresholds of the leg, foot and sole were large and those of the forehead, cheek, chin and palm were small for each generation. The cold/warm thresholds for the elderly women were larger than those for young women. In particular, the threshold of the leg was significantly larger for the elderly women than it was for the young women, and it increased with advancing age. The cold/warm thresholds of the leg, foot, and sole were found to be obviously age-dependent. The cold/warm threshold values of the trunk were between those of the face and lower extremities, with the exception of the anterior shoulder. As a result of principal component analysis, the first component was interpreted as a size factor which explained the intensity of the cold/warm threshold sensitivity of the whole body. The value of the first component of each subject increased with age in the 60's to the 80's. The second component obtained from the cold/warm thresholds analysis was interpreted as a factor which explained the contrast between the sensitivity of the anterior shoulder and chest, and buttock and foot for the cold sensation and the contrast between the sensitivity of the posterior leg and sole, and buttock and anterior neck for the warm sensation.