The effects of age and sex on the body cooling rates.
Abstract
When the head was cooled for 30 minutes, sublingual
temperature fell by as much as 4.45°C below oesophageal
which remained steady. Insulation of the head prevented
this local cooling. There was an increased flow of cold
parotid saliva when the head was exposed to cold and this
appeared to be the major factor which depressed sublingual
temperature. The estimation of deep body temperature from
sublingual readings is meaningful only if precautions are
taken to prevent local cooling of the head.
Local cooling has been shown to depress temperature
measured from the external auditory canal. A portable
device (The Zero Gradient Aural Thermometer) was developed
and used to measure external auditory canal temperature
keeping the outer ear, monitored by a second thermistor,
at the same level as the canal by servo-controlled heating.
Measured in this way, aural temperature was always within
0.35°C of oesophageal under a variety of thermal stress.
Rates of fall of deep body temperature in 28 children
swimming in cold water correlated highly with overall subcutaneous
fat thickness and a higher' correlation was obtained
when allowance was made for differences in surface area/mass
ratios. Young swimmers who were thin and with high surface
area/mass ratios were shown to be at considerable risk from
death due to hypothermia when swimming in water as warm as
20.30 C. Differences in fat distribution had a small effect
on cooling rates.
Cooling in air at 10°C, women generally had greater falls
in deep body temperature than men even allowing for differences
in surface area/mass ratio and subcutaneous fat thickness.
This was mainly due to a smaller metabolic response to cold
in the women.
Authors
Sloan, R.E.G.Collections
- Theses [3706]