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Jerrold Petrofsky, Scott Lee, Chris Patterson, Melissa Cole, Brian Stewart
Med Sci Monit 2005; 11(11): CR515-521
Background: While sweat production in response to heat is impaired in peoplewith diabetes, sweat production has not been examined during isometric exercise. Material/Methods: Eightsubjects with type 2 diabetes and 9 control subjects exerted a fatiguing isometric contraction of thehandgrip muscles at a tension of 40% of the maximum voluntary strength (MVC) after exposure to a 32 degC environment for 30 min. compared to 10 controls and 10 subjects with diabetes exposed to a 39 deg Cenvironment. Results: Sweat was impaired to all areas of the body during heat exposure in patients withdiabetes under both environmental conditions. For example, on the chest, the average sweat rates afterexposure to the 32 deg environment was 259.2+/-55.2 nanoliters/min in control subjects and 198.3+/-46.2nanoliters/min for subjects with diabetes. Compared to the 32 deg C environment, control subjects increasedsweat in all 4 areas proportionally more than subjects with diabetes. Sudomotor rhythm was present insweat in control subjects at a rate of repetition of 11 and 50 seconds but almost absent in subjectswith diabetes. During exercise, sweat rates slowly increased from the beginning to the end of the exercise.But the head of the subjects with diabetes showed hypersweating while the other areas showed diminishedsweating compared to control subjects. Conclusions: Thus some of the impairment in sweating may be dueto central mechanisms associated with heat sensitivity or in the hypothalamus and not to the sweat glandsthemselves.