Hypernatremia and intravenous fluid resuscitation in collapsed ultramarathon runners

Sudden death in young athletes: Is it preventable?

Sudden death in young athletes is a rare but always dramatic condition. Unlike all other rare diseases, the estimate of its real incidence is made complex not only because of the uncertain number of correctly identified cases (numerator) but also because of the uncertain estimation of the real number of the reference population, the athletes (denominator). New elements of complexity are also emerging with regard to prevention. The current two pillars of prevention are pre-participation screening (proactive strategy) and promoting use / access to the automated external defibrillator (reactive strategy). The standardization of procedures implemented over the past two decades for pre-participation screening can now allow us to assess the impact of this approach. The result is complex to evaluate. While screening may allow the identification of conditions potentially associated with SDA, and therefore the adoption of specific treatments, in about 0.4% of screened subjects, a single study investigated the yield in terms of mortality showing a positive predictive value of 4.7% with 25% sensitivity. Conversely, the reactive strategy appears considerably effective, due to the widespread use of the automated external defibrillators in sports facilities, calling for a homogeneous implementation worldwide. On a broader perspective, the vast attention devoted to SDA prevention in the world of sports represents a major driver for transfer of a reactive prevention strategy to the general population.

Effect of Sodium Supplements and Climate on Dysnatremia During Ultramarathon Running

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.

Wilderness Medical Society Clinical Practice Guidelines for the Management of Exercise-Associated Hyponatremia: 2019 Update

Exercise-associated hyponatremia (EAH) is defined by a serum or plasma sodium concentration below the normal reference range of 135 mmol·L-1 that occurs during or up to 24 h after prolonged physical activity. It is reported to occur in individual physical activities or during organized endurance events conducted in environments in which medical care is limited and often not available, and patient evacuation to definitive care is often greatly delayed. Rapid recognition and appropriate treatment are essential in the severe form to increase the likelihood of a positive outcome. To mitigate the risk of EAH mismanagement, care providers in the prehospital and in hospital settings must differentiate from other causes that present with similar signs and symptoms. EAH most commonly has overlapping signs and symptoms with heat exhaustion and exertional heat stroke. Failure in this regard is a recognized cause of worsened morbidity and mortality. In an effort to produce best practice guidelines for EAH management, the Wilderness Medical Society convened an expert panel in May 2018. The panel was charged with updating the WMS Practice Guidelines for Treatment of Exercise-Associated Hyponatremia published in 2014 using evidence-based guidelines for the prevention, recognition, and treatment of EAH. Recommendations are made based on presenting with symptomatic EAH, particularly when point-of-care blood sodium testing is unavailable in the field. These recommendations are graded on the basis of the quality of supporting evidence and balanced between the benefits and risks/burdens for each parameter according to the methodology stipulated by the American College of Chest Physicians.

Dysnatremia among runners in a half marathon performed under warm and humid conditions

Background

Dysnatremia has been associated with sports activity, especially long-distance running and endurance sports. High fluid intake is associated with hyponatremia. This study aims to evaluate dysnatremia and risk factors in half-marathon runners under warm and humid environmental conditions.

Methods

A cross-sectional study was performed among randomly selected runners in the 2017 Cali half marathon. Runners on diuretic therapy or with a known history of kidney disease were excluded. Participants went through a 2-day assessment. Previous medical history, training history, body mass index and running history were determined in the first assessment. Symptoms of dysnatremia and level of fluid consumption during the race were registered during the second assessment and post-run blood sampling for serum [Na+] was also undertaken.

Results

130 runners were included in the study. The complete 2-day assessment was performed on 81 participants (62%) that were included in the final analysis. No cases of hyponatremia were found; instead, there were six cases of asymptomatic hypernatremia (7.4%). This hypernatremia had a statistically significant association with lower frequency (p=0.01) and volume of fluid intake during the race (water: p=0.02, Gatorade: p=0.04).

Conclusion

Hyponatremia has been associated with high fluid intake in races performed under cool weather, such as the Boston Marathon during spring. In contrast, hypernatremia was found in a half marathon in warm and humid weather, which was associated with lower volume and frequency of fluid intake, suggesting that under warm and humid conditions, a median fluid intake of 900 mL during the race could prevent this event.

Exercise-Associated Hyponatremia, Hypernatremia, and Hydration Status in Multistage Ultramarathons

OBJECTIVE

Dysnatremia and altered hydration status are potentially serious conditions that have not been well studied in multistage ultramarathons. The purpose of this study was to assess the incidence and prevalence of exercise-associated hyponatremia (EAH) (Na⁺ <135 mmol·L^-1) and hypernatremia (Na⁺ >145 mmol·L^-1) and hydration status during a multistage ultramarathon.

METHODS

This study involved a prospective observational cohort study of runners competing in a 250-km (155-mile) multistage ultramarathon (in the Jordan, Atacama, or Gobi Desert). Prerace body weight and poststage (stage [S] 1 [42 km], S3 [126 km], and S5 [250 km]) body weight and serum sodium concentration levels were obtained from 128 runners.

RESULTS

The prevalence of EAH per stage was 1.6% (S1), 4.8% (S3), and 10.1% (S5) with a cumulative incidence of 14.8%. Per-stage prevalence of hypernatremia was 35.2% (S1), 20.2% (S3), and 19.3% (S5) with a cumulative incidence of 52.3%. Runners became more dehydrated (weight change <-3%) throughout the race (S1=22.1%; S3=51.2%; S5=53.5%). Body weight gain correlated with EAH (r=-0.21, P = .02). Nonfinishers of S3 were significantly more likely to have EAH compared with finishers (75% vs 5%, P = .001), but there was no difference in either EAH or hypernatremia between nonfinishers and finishers of S5.

CONCLUSIONS

The incidence of EAH in multistage ultramarathons was similar to marathons and single-stage ultramarathons, but the cumulative incidence of hypernatremia was 3 times greater than that of EAH. EAH was associated with increased weight gain (overhydration) in early stage nonfinishers and postrace finishers.

Exercise-Associated Hyponatremia: 2017 Update

Exercise-associated hyponatremia (EAH) was initially described in the 1980s in endurance athletes, and work done since then has conclusively identified that overdrinking beyond thirst and non-osmotic arginine vasopressin release are the most common etiologic factors. In recent years, EAH has been described in a broader variety of athletic events and also has been linked to the development of rhabdomyolysis. The potential role of volume and sodium depletion in a subset of athletes has also been described. This review focuses on the most recent literature in the field of EAH and summarizes key new findings in the epidemiology, pathophysiology, treatment, and prevention of this condition.

Intravenous fluid use in athletes

CONTEXT

Time allowing, euhydration can be achieved in the vast majority of individuals by drinking and eating normal beverages and meals. Important to the competitive athlete is prevention and treatment of dehydration and exercise-associated muscle cramps, as they are linked to a decline in athletic performance. Intravenous (IV) prehydration and rehydration has been proposed as an ergogenic aid to achieve euhydration more effectively and efficiently.

EVIDENCE ACQUISITION

PubMed database was searched in November 2011 for all English-language articles related to IV utilization in sport using the keywords intravenous, fluid requirements, rehydration, hydration, athlete, sport, exercise, volume expansion, and performance.

RESULTS

Limited evidence exists for prehydration with IV fluids. Although anecdotal evidence does exist, at this time there are no high-level studies confirming that IV prehydration prevents dehydration or the onset of exercise-associated muscle cramps. Currently, there are no published studies describing IV fluid use during the course of an event, at intermission, or after the event as an ergogenic aid.

CONCLUSION

The use of IV fluid may be beneficial for a subset of fluid-sensitive athletes; this should be reserved for high-level athletes with strong histories of symptoms in well-monitored settings. Volume expanders may also be beneficial for some athletes. IV fluids and plasma binders are not allowed in World Anti-Doping Agency-governed competitions. Routine IV therapy cannot be recommended as best practice for the majority of athletes.

Study of injury and illness rates in multiday ultramarathon runners

PURPOSE

This study aimed to describe injury and illness rates in runners competing in 7-d, 250-km off-road ultramarathon events.

METHODS

Three hundred ninety-six runners competing in the RacingThePlanet© 4 Desert Series ultramarathon races from 2005 to 2006 were prospectively followed. Descriptive analyses were used to evaluate overall injury/illness rates, types of injuries/illnesses, and diagnoses for all medical encounters. Multivariate linear regression was used to estimate the risk of number of injuries/illnesses and 95% confidence intervals associated with age, sex, and race completion time.

RESULTS

Eight-five percent of runners representing a total of 1173 medical encounters required medical care. The overall injury/illness rates were 3.86 per runner and 65 per 1000-h run. Almost 95% were minor in nature, owing to skin-related disorders (74.3%), musculoskeletal injuries (18.2%), and medical illnesses (7.5%). Medical illnesses were more likely on the first day of the race, whereas musculoskeletal and skin injuries were more likely on day 3 or 4. A 10-yr increase in age was associated with 0.5 fewer injuries/illnesses, and females had 0.16 more medical illnesses compared with males.

CONCLUSIONS

Despite the extreme nature and harsh environments of multiday ultramarathon races, the majority of injuries or illnesses are minor in nature. Future studies are needed to evaluate additional factors contributing to injuries.

Al Andalus Ultra Trail: an observation of medical interventions during a 219-km, 5-day ultramarathon stage race

OBJECTIVE

To record the injuries and health problems suffered by ultramarathon runners during a 219-km, 5-day stage race and to help race organizers plan medical provision for these events.

DESIGN

Observational study.

SETTING

Al Andalus Ultra Trail 2010, in southern Spain.

PARTICIPANTS

All 69 ultramarathon runners.

MAIN OUTCOME MEASURES

Total numbers and percentages of each clinical encounter with a health professional and their respective health problems.

RESULTS

Sixty-nine competitors started the race, and 39 runners were seen with a medical problem (56.5%). There were a total of 99 clinical encounters. The most common reasons for consulting were foot blisters (33.3%), followed by chafing (9.1%). Lower limb musculoskeletal injuries accounted for 22.2%, predominantly affecting the knee.

CONCLUSIONS

This is the first report of a multistage ultramarathon race where medical coverage was present throughout and has reported on musculoskeletal, dermatological, and other medical problems. When providing medical coverage for stage events, the medical team needs to promote practices that minimize injury and address both running-related injuries and non-running-related injuries, taking account of environmental conditions.

A study of serum sodium level among Hong Kong runners

OBJECTIVE

Hyponatremia and the associated life-threatening complications have emerged as an important issue among marathon runners. This study was conducted to estimate the serum sodium level among local marathon runners and to identify the associated risk factors of dysnatremia.

DESIGN

Prospective observational cohort study.

SETTING

Hong Kong Marathon 2008.

PARTICIPANTS

Subjects were approached at their convenience to participate in the study. Only full-marathon runners were recruited. They were to have had an unremarkable medical and drug history.

INTERVENTIONS

Demographic data, training information, previous marathon experience, anticipated drinking strategy, details of fluid consumption throughout the race, weight change, finishing time, and physical complaint.

MAIN OUTCOME MEASURES

Post-race serum sodium level.

RESULTS

Of the 6488 entries to the race, 370 runners (5.7%) were recruited. Among them, 272 (73.5%) completed the race and attended for blood sampling and data collection. One runner (0.4%) had hyponatremia (133 mmol/L) and 35 runners (12.9%) had hypernatremia (>145 mmol/L), whereas 236 runners (86.7%) had normal serum sodium (135-145 mmol/L) after the race. No symptomatic dysnatremia was found. A mean weight reduction of 0.70 kg was found after the race. An average of 1.9 L of fluid was consumed during the race and 2.5 L if the fluid consumed immediately before and after the race was also included. Hypernatremia was seen in runners who were better trained before the race, those who performed better, and those who drank less water after the race.

CONCLUSIONS

This is the largest prospective observational cohort study of dysnatremia conducted on athletes completing a standard marathon in Asia. No case of symptomatic dysnatremia was found.