The effect of aging on conductive heat exchange in the skin at two environmental temperatures.
BACKGROUND
Ageing diminishes the blood flow (BF) response of the skin to autonomic stressors. While the diminished response of skin BF to global heating has been well documented, the effect of this reduction in skin BF on the ability of the skin to dissipate heat has not. When heat is added to the skin by the application of hot packs, if heat is not adequately removed, the skin can become dangerously hot and become damaged. The present investigation examined the heat dissipating properties of the skin in older individuals. This study has importance for the therapeutic application of hot packs which might cause burns easier in older people.


METHODS
In the present investigation, 10 younger and 10 older subjects were examined. The average age of the younger group was 25.9+/-3.4 years and the older group was 60 +/- 5.8 years. Heat was applied through a 49 gram brass probe that was heated to 41 degrees C and by a Peltier junction in a cool and warm environment.


RESULTS
Skin required about 20 calories of heat to raise skin temperature 1 degrees C the cool room and double this Figure in the warm room. Ageing reduced the caloric requirement to increase skin temperature under both conditions (p < 0.01).


CONCLUSIONS
The results of the experiments showed that older individuals had impaired ability of the skin to dissipate heat in both environments. Special precautions should be taken in physical therapy when applying hot packs in older populations.
Petrofsky
Jerrold S
JS
Department of Physical Therapy, School of Allied Health Professions, Loma Linda University, Loma Linda, CA 92350, USA. jpetrofsky@llu.edu
Lohman
Everett
E
Suh
Hye Jin
HJ
Garcia
Jason
J
Anders
Alexa
A
Sutterfield
Cassandra
C
Khandge
Chetan
C
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology*; D004777:Environment; D006358:Hot Temperature; D006801:Humans; D008875:Middle Aged; D012881:Skin Temperature / Q000502:physiology*; D013696:Temperature