Prevalence of AKI was 63%-78% during multistage ultramarathons. Female sex, lower pack weight, and greater weight loss were associated with renal impairment.

Objective: Analyze the effect of sodium supplementation, hydration, and climate on dysnatremia in ultramarathon runners. Design: Prospective observational study. Setting: The 2017 80 km (50 mile) stage of the 250 km (150 mile) 6-stage RacingThePlanet ultramarathon in 2017 Chilean, Patagonian, and 2018 Namibian, Mongolian, and Chilean deserts. Participants: All race entrants who could understand English were invited to participate, with 266 runners enrolled, mean age of 43 years (± 9), 61 (36%) females, average weight 74 kg (± 12.5), and average race time 14.5 (± 4.1) hours. Post-race sodium collected on 174 (74%) and 164 (62%) participants with both the blood sample and post-race questionnaire. Intervention: Weight change and finish line serum sodium levels were gathered. Main outcome measures: Incidence of exercise-associated hyponatremia (EAH; <135 mmol·L−1) and hypernatremia (>145 mmol·L−1) by sodium ingestion and climate. Results: Eleven (6.3%) runners developed EAH, and 30 (17.2%) developed hypernatremia. Those with EAH were 14 kg heavier at baseline, had significantly less training distances, and averaged 5 to 6 hours longer to cover 50 miles (80 km) than the other participants. Neither rate nor total ingested supplemental sodium was correlated with dysnatremia, without significant differences in drinking behaviors or type of supplement compared with normonatremic runners. Hypernatremic runners were more often dehydrated [8 (28%), −4.7 kg (± 9.8)] than EAH [4 (14%), −1.1 kg (± 3.8)] (P < 0.01), and EAH runners were more frequently overhydrated (6, 67%) than hypernatremia (1, 11%) (P < 0.01). In the 98 (56%) runners from hot races, there was EAH OR = 3.5 [95% confidence interval (CI), 0.9-25.9] and hypernatremia OR = 8.8 (95% CI, 2.9-39.5) compared with cold races. Conclusions: This was the first study to show that hot race climates are an independent risk factor for EAH and hypernatremia. Sodium supplementation did not prevent EAH nor cause hypernatremia. Longer training distances, lower body mass, and avoidance of overhydration were shown to be the most important factors to prevent EAH and avoidance of dehydration to prevent hypernatremia.

Introduction-Ultramarathon running is increasing in popularity worldwide, as is the growing body of research on these athletes. Multiple studies have examined acute kidney injury through estimated baseline creatinine (Cr) and glomerular filtration rate (GFR). Values are estimated through an age-based formula of GFR and the modification of diet in renal disease (MDRD) equation. However, the accuracy of this practice in a cohort of healthy athletes is unknown.Methods-A prospective analysis of the first 40-km (25-mi) stage of 6-stage 250-km (155-mi) multistage ultramarathons in the Sahara, Namibia, Atacama, and Gobi Deserts. Runners had prerace measured baseline Cr compared to estimated values through age-based estimated GFR and back calculation of Cr through the MDRD equation.Results-Forty-eight participants (27% female, age 39 §10 y) had Cr values analyzed. The mean measured Cr was 0.99 §0.17, which was 11% higher than an estimated Cr of 0.88 §0.14 (P<0.01). Estimated age-based GFR was 95.9 §5.8 mLÁmin ¡1 compared to GFR based on measured Cr and MDRD of 86.1 §14.6 (P<0.001).Conclusions-Estimated values of GFR and Cr by standard age-based values and MDRD equation were significantly inaccurate, which would overinflate the incidence of acute kidney injury. Future studies should devise a new model for estimation of baseline Cr that is validated in this population.

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These data then were analyzed to provide a descriptive analysis of the epidemiology of scuba diving-related injuries. Results.-The NEISS representative dataset produced 122 unique cases that resulted in an estimated total national injury burden over this 3-year period of 4151 cases. The most common injury diagnosis (2188, 52.7%) was coded as "other." Musculoskeletal-related injuries were noted in 1072 (26%) cases, 2439 (58.7%) patients were discharged, and 861 (20.7%) were treated and transferred to another facility. Similar numbers of patients presented to small, medium, and very large facilities. Conclusions.-Scuba diving injuries present to emergency departments of all sizes, and providers at small-and medium-sized facilities need to be prepared to treat these patients. The injuries identified included many musculoskeletal injuries that commonly occur with moving heavy equipment in a wet environment. Future safety initiatives aimed at the diving community should provide additional focus on the safe movement of equipment and increase awareness of the risks posed by the wet environment.