The influence of elevated body temperature on skin perspiration

To evaluate the influence of an elevated rectal temperature on sensible and insensible perspiration the evaporative water losses from the skin of 33 female and 41 male surgical patients with fever were recorded with an evaporimeter. It was found that the patients were generally in a state of normal insensible perspiration. In some of the patients, however, intermittent sensible sweating was observed. In all cases when the patients were sweating the rectal temperature was above 39.5 degrees C and the cutaneous water loss was increased 6-8 times over basal values. The sweating periods, however, took place only during 4-7 hours per 24-hour period in an ambient temperature of about 23.5 degrees C. This means that in a comfortable indoor environment an extra 600 ml per day of fluid should be supplied to patients with highly elevated body temperature in order to compensate for an increased cutaneous water loss. In a tropical or subtropical climate the extra fluid supply has to be substantially increased.