Body Temperature of the Aged-The Effect of Aging on the Cutaneous Sensory Points

Abstract

The disturbance of the responses for the cold stress are more distinguished than these for the heat stress in the aged, and the principal characteristic of the thermoregulation in the aged is the suppressed responses resulted from the decrease of the sensibility for the thermal stimuli. But the regulatory mechanismus, which chalacterize the temperature regulation in the aged, was not investigated in detail till now. On the other hand the distribution of the sensory points in various cutaneous area, was already investigated minutely in the 1920's, and after that the investigation about the cutaneous sensation is mainly concerned with the problemes of electrophysiological characteristics of the sensory receptors. The effect of aging on the threshold of cutaneous sensation was also reported from several investigators, but there is no report about the effect of aging on the distribution of sensory points.
As the first trial for studing the characteristic of the thermoregulatory mechanism in the aged, the frequency of the cutaneous cold points and, for the comparison, also of cutaneous pain points in the aged was investigated. The test was performed in 8 areas of the body surface, i.e, forehead, neck, breast, belly, forearm, back of hand, calf and back of foot of each peoples both of the aged group of 30 peoples (73±4 years old) and of the control group of 20 peoples (26±5 years old). To estimate the frequency of the cold and pain points, the number of the points, which could be perceived cold or pain resp., in 100 trials in 2×2cm square area was measured. The results obtained was as follows:
1) The decrease of the frequencies of both cold and pain points of the aged group in comparison with these of the control group is significant in all area, except in the pain point of the forehead.
2) The frequency of the cold points was higher in the body trunk area and lower in the peripheral extremity area, especially in the calf and in the back of foot. The decrease of the frequency of the cold points in the aged group was marked also in the calf and in the back of foot.
3) The regional difference of the frequency of the cutaneous pain points and the decrease of the frequency of the pain points in the aged is less distinguished than these of the cold points. But the frequency of the pain points in the back of foot is markedly low and decreased markedly in the aged.
The results suggest that the decrease of the cold points is affected to the suppressed sensibility for the thermal stimuli and that there is a cutaneous regional difference in the distribution of the sensory points and in their decrease through aging.