Ibuprofen Ingestion Prior To Running In The Heat And Risk Of Acute Kidney Injury

Athletes regularly consume ibuprofen to mitigate pain and injuries associated with training and competition, which often occur in hot environments. Exercise in the heat increases the risk of acute kidney injury (AKI), and ibuprofen consumption may independently increase AKI risk. However, it is not known if ibuprofen consumption prior to exercise in the heat exacerbates markers of AKI risk. PURPOSE: We tested the hypothesis that ibuprofen consumption prior to running in the heat exacerbates AKI markers. METHODS: In a randomized, crossover, double bind design, 11 recreationally active runners (6 female) consumed 600 mg of ibuprofen or placebo 12- and 1-hour prior to running for 1-hour at 65% VO2max in a hot environment (35 °C, 45% RH). Core temperature (Tc) was recorded every 5 minutes during the exercise protocol. Urine samples were collected pre-, post- and 1-hour post-exercise, and urine flow rate (UFR) was measured for 1 hour pre- and post-exercise. Urine was analyzed to assess urine specific gravity (USG) and markers of AKI risk (product of insulin-like growth factor-binding protein 7; IGFBP7 & tissue inhibitor of metalloproteinase 2; TIMP-2, and neutrophil gelatinase-associated lipocalin; NGAL). Due to non-normally distributed data, analyses for urinary [IGFBP7•TIMP-2] and NGAL were completed after log10 transformation. RESULTS: Peak Tc was not different between the ibuprofen (39.0 ± 0.5 °C) and placebo (39.0 ± 0.5 °C) conditions (p = 0.73). There was an increase of urinary log10 [IGFBP7•TIMP-2] (p < 0.001) from pre-exercise (-2.6 ± 0.2) to peak post-exercise (-0.7 ± 0.8), with no difference between conditions (p = 0.29). Similarly, there was an increase of urinary log10 NGAL (p < 0.001) from pre-exercise (0.48 ± 0.46) to peak post-exercise values (1.24 ± 0.3), with no difference between conditions (p = 0.38). No differences were found between conditions for UFR (p = 0.25), but there was a decrease from pre- (473 ± 184 mL/h) to post-exercise (77 ± 65 mL/h) (p < 0.001). There was no main effect of condition on USG (p = 0.23). A significant, positive correlation was found between peak Tc and peak urinary log10 [IGFBP7•TIMP-2] (r = 0.68, p < 0.001). CONCLUSION: Ibuprofen ingestion prior to running in the heat does not worsen markers of AKI risk. Peak Tc is positively associated with changes in markers of AKI risk.