768-km Multi-Stage Ultra-Trail Case Study-Muscle Damage, Biochemical Alterations and Strength Loss on Lower Limbs

Effect of Two Hydration Strategies on CapillarySodium Concentrations in Runners Participating in 170-km Trail Race: The 2015 UltraTrail du Mont-Blanc Experience

OBJECTIVE

This study assessed the impact of 2 hydration strategies on capillary sodium concentrations during Ultra-Trail du Mont-Blanc (UTMB) 2015.

DESIGN

Prospective exposed/nonexposed cohort study.

SETTING

Ultra-Trail du Mont Blanc 2015 (170 km).

PARTICIPANTS

Thousand five hundred sixty-three registered runners of UTMB 2015 asked to predefine their hydration strategy as either "drinking to thirst" or any other mode ("not drinking to thirst").

INTERVENTION

One hundred "drinking to thirst" participants were randomly selected and paired (sex and age) with 96 "not drinking to thirst" participants. Participant weight and capillary sodium concentrations were measured before and after the race.

MAIN OUTCOME MEASURES

Variations of capillary sodium concentrations and weight during the trail according to predefine hydration strategy as either "drinking to thirst" or "not drinking to thirst." Adverse events were recorded. P < 0.05 was considered statistically significant.

RESULTS

Among 196 participants, 88 (62 finishers) "drinking to thirst" and 87 (64 finishers) "nondrinking to thirst" participants were analyzed, respectively. There was no difference in the change in capillary sodium concentrations prerace to postrace between the groups (1.5 ± 4.4 vs 1.5 ± 4.7 mEq/L, P = 0.98). The change in participant weight was also not different (P = 0.3877). Hypernatremia or hyponatremia were reported in 19 of 88 (21.6%) and 24 of 87 (27.6%) in "drinking to thirst" and "non-drinking to thirst" participants, respectively (P = 0.20). The incidence of adverse events was not different between the groups.

CONCLUSION

This study observed no impact of hydration strategy on the change in capillary sodium concentrations before and after UTMB 2015.

Bone Turnover Alterations after Completing a Multistage Ultra-Trail: A Case Study

A series of case studies aimed to assess bone and stress fractures in a 768-km ultra-trail race for 11 days. Four nonprofessional male athletes completed the event without diagnosing any stress fracture. Bone turnover markers (osteocalcin (OC), serum C-terminal cross-linking telopeptide of type I collagen (CTX), bone-specific alkaline phosphatase (BALP), and serum turnover calcium (Ca2+)) were assessed before (pre) and after the race (post) and on days two and nine during the recovery period (rec2 and rec9), respectively. Results showed: post-pre-OC = -45.78%, BALP = -61.74%, CTX = +37.28% and Ca2+ = -3.60%. At rec2 and rec9, the four parameters did not return to their pre-run levels: OC, -48.31%; BALP, -61.66%; CTX, +11.93% and Ca2+, -3.38%; and OC = -25.12%, BALP = -54.65%, CTX = +93.41% and Ca2+ = +3.15%), respectively. Our results indicated that the ultra-trail race induced several changes in bone turnover markers, uncoupling of bone metabolism, increased bone resorption: OC and BALP and suppressed bone formation: CTX and Ca2+. Bone turnover markers can help determine the response of bone to extreme effort and might also help predict the risk of stress fractures.

Acute Kidney Injury and Hyponatremia in Ultra-Trail Racing: A Systematic Review

Background and objectives: Ultra-trail races can cause episodes of acute kidney injury (AKI) and exercise-associated hyponatremia (EAH) in healthy subjects without previous renal pathology. This systematic review aims to review the incidence of these two syndromes together and separately taking into account the length and elevation of the ultra-trail race examined. Materials and Methods: A systematic review was conducted through electronic search in four electronic databases (PubMed, EBSCO, Web of Science and Alcorze). Results: A total of 1127 articles published between January 2006 and December 31, 2021 were included, 28 of which met the inclusion criteria. The studies were categorized according to the length and stages of the race in four categories: medium (42 to 69 km), long (70 to 99 km), extra (>100 km) and multi-stage if they included various stages. A total of 2950 runners (666 females and 2284 males) were extracted from 28 publications. The AKI incidence found was 42.04% (468 cases of 1113), and 195 of 2065 were diagnosed with EAH, accounting for 9.11%. The concurrence of both pathologies together reached 11.84% (27 individuals) from a total of 228 runners with AKI and EAH simultaneously analyzed. Sorted by race category, the AKI+EAH cases were distributed as follows: 18 of 27 in the extra (13.63% and n = 132), 4 in the large (5.79% and n = 69) and 5 in the medium category (18.15% and n = 27). Conclusions: According to these results, extra and medium races showed a similar incidence of AKI+EAH. These findings underline the importance of the duration and intensity of the race and may make them responsible for the etiology of these medical conditions. Due to their variable incidence, EAH and AKI are often underdiagnosed, leading to poorer prognosis, increased condition seriousness and hindered treatment. The results of this review urge participants, coaches and race organizers to take measures to improve the early diagnosis and urgent treatment of possible EAH and AKI cases.