Physical insulation of healthy men and women over 60 years

¹ Department of Physiology, Yonsei University College of Medicine, Seoul, Korea, and Department of Physiology, State University of New York at Buffalo, Buffalo, New York

Maximal body insulation [I = (rectal temp. – skin temp.)/rate of skin heat loss] of healthy Korean men and women (17 each) over 60 years of age was determined by a method applied earlier to diving women of Korea (Rennie et al. J. Appl. Physiol. 17: 961, 1962). The critical water temperature was similar for males and females, ranging from 28–33 C. The water temperature at which 50% of subjects shivered was 31.2 C for both groups. This value is identical to that of young Korean men but is significantly higher than that of young Korean women. When a comparison was made at 31 C water, the extent of reduction in rectal temperature was, in the aged group, greater in males than in females, and was also greater in the aged than in the young. However, these differences could be accounted for mostly by the difference in subcutaneous fat thickness. When the values of I were considered as a function of the subcutaneous fat thickness, there was no difference either between old males and females or between the aged and young Korean subjects. This indicates that maximal body insulation due to physical factors does not change as a function of age.

Note:
(With the Technical Assistance of Jin Kyung Kim)

Submitted on January 15, 1964