Fluctuations of Skin Temperature under Changing Ambient. Temperature in Relation to Age.

Skin temperature, oral temperature and sensation were measured, and fluctuations of skin temperature were investigated by frequency analysis, to examine age-related differences in thermo-regulated response under changing ambient temperature. The subjects were ten older (age 53-65) and ten younger (age 19-21) women, and they were kept at rest during the 70 minutes of exposure to three consecutive temperature changes (25→34→21°C). In the initial thermo-neutral period, and during the period of increasing ambient temperature, skin temperatures were lower for the older group, but the decrease in ambient temperature produced a slower rate of skin temperature change for the older group than the younger group. Similar changes in oral temperature and hedonic rating were also observed. These results show the delay of response to the cold environment for the older group. The low frequency component of the power spectrum increased during the decreasing period of ambient temperature for both younger and older groups, and the slope of 1/f spectral pattern became steeper than that observed during the increasing period. This reflects the increased activity of thermo-regulation during the decreasing period of ambient temperature. Effects of age were not noticeable by frequency analysis.