Effect of Urinary Sheath Use on Hydration Status of Fighter Pilots Under Severe Thermal Stress: An Observational Study

Abstract

The use of a US successfully mitigates preflight dehydration, as reflected by decreases in USG, showing that pilots, at least partially, abandon preflight voluntary hypohydration strategies. It also favored water and food intake during flight without enhancing inflight dehydration, shown by the parallel increases in loss (urine and sweat) when wearing a US.

Increased Serum Levels of Proinflammatory Cytokines Are Accompanied by Fatigue in Military T-6A Texan II Instructor Pilots

“…Urine specific gravity and blood lactate values were within the normative clinical range ( Antinone and Kress, 2009 ; Brescon et al, 2018 ) at each data collection time point, without significant changes occurring from baseline to final ( Tables 2 , 3 ). Venous blood chemistry values also showed no changes from baseline to final ( Table 3 ).…”

“…We considered whether dehydration, an ever-present physiologic stressor within the tactical aviation environment, could have been present and contributed to our findings. Urine specific gravity, measured at the same time venous blood was collected, suggests that the aviators met criteria for dehydration, defined by specific gravity measures ≥1.020 ( Popowski et al, 2001 ), during baseline data collection, and were “hypohydrated,” defined by specific gravity measures ≥1.013 but ≤1.020 ( Brescon et al, 2018 ), during the remainder of the study period. As an additional measure, we assessed whether hydration status was accompanied by plasma loss and hemoconcentration, manifest as increased red blood cell mass per unit of plasma ( Watanabe et al, 2020 ).…”