Local inhibition of carbonic anhydrase does not decrease sweat rate.

Background: The purpose of this study was to measure sweat rate during exercise in the heat after directly inhibiting carbonic anhydrase (CA) in eccrine sweat glands via transdermal iontophoresis of acetazolamide. It was hypothesized that if CA was important for sweat production, local administration of acetazolamide, without the confounding systemic effects of dehydration typically associated with past studies, would have a significant effect on sweat rate during exercise. Methods: Ten healthy subjects volunteered to exercise in the heat following acetazolamide or distilled water iontophoresis on the forearm. Results: The distilled water iontophoresis site had a mean sweat rate during exercise in the heat of 0.59±0.31 μL/cm²/min, while the acetazolamide iontophoresis site had a mean sweat rate of 0.63±0.36 μL/cm²/min (p>0.05). Conclusions: The most important finding of the current study was that iontophoresis of acetazolamide did not significantly decrease sweat rate during exercise in the heat. Such results suggest that in past studies it was systemic dehydration, and not CA inhibition at the level of the sweat gland, that caused the reported decreased sweat rate. [ABSTRACT FROM AUTHOR]