284 Intestinal hyperpermeability from an exercise/heat/NSAID challenge
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Intestinal hyperpermeability (‘leaky gut’) has been postulated as a potential trigger for heat stress in endurance athletes. To assess the efficacy of interventions to counteract leaky gut it is necessary to both induce and detect intestinal hyperpermeability. We aimed to determine whether a specific challenge of exercise, heat and NSAID ingestion could elicit intestinal hyperpermeability as measured by the lactulose to rhamnose excretory ratio (LRER). Recreational runners (3 males, 2 females ; 29 ± 6y; VO2max 57 ± 7 mL kg-1min-1) participated. Gut permeability was assessed by LRER, with 6h urine collection and analysis by GCMS(sim), on three occasions: twice under rest and once under challenge (70% VO2max treadmill run for 45min at 28°C and 50% relative humidity after ingestion of 2.4g aspirin in split dose 12h apart). For comparison of LRER between conditions, 90% confidence limits (CL) were derived via the t-statistic and were standardized for interpretation of magnitude. LRER showed little change in the second resting condition relative to the first (factor change 1.1; 90%CL 0.9 - 1.2). Relative to the mean of the resting conditions, exercise produced a very large increase in LRER (factor change 7.0; 90%CL 3.4 - 15).The specific challenge of exercise in the heat after NSAID ingestion used here is an effective way of inducing intestinal hyperpermeability that can be detected by the LRER. As such it provides a useful model to assess the efficacy of interventions to counteract leaky gut, and hence, potentially, to reduce the susceptibility of endurance athletes to heat stress.