Evaluation of gender differences in urine specific gravity and serum electrolytes in response to varied fluid intake...

Heat casualties and other conditions related to suboptimal fluid intake (FI) are common in the military. Current methods to assess FI do not address gender differences or medication use, specifically non-steroidal anti-inflammatory drugs (NSAIDs), which are commonly used in the field. Nine men and six women were prospectively studied while stationed in Saudi Arabia. Urine specific gravity and serum electrolytes were monitored as FI was varied before and after daily ibuprofen (IBP) ingestion. IBP impaired urinary dilution in both men and women, but differences were not statistically significant pre- and post-IBP or between genders. Use of IBP or other NSAIDs may confound usual methods to ensure adequate FI, and soldiers should be specifically questioned about their use before such assessments.