Exercise-induced Hyponatremia Research Articles

Exercise-Induced Hyponatremia: An Assessment of the International Hydration Recommendations Followed During the Gran Trail De Peñalara and Vitoria-Gasteiz Ironman Competitions.

IntroductionHyponatremia often occurs during the practice of endurance sports. We evaluated the impact on hyponatremia of the hydration recommendations of the Third International Exercise-Associated Hyponatremia Consensus Development Conference 2015 (3IE-AHCD) during the 2017 Gran Trail de Peñalara marathon (GTP) and the Vitoria Gasteiz Ironman triathlon (VGI).MethodsProspective study of GTP and VGI athletes participating in four information sessions in the months prior to the events, to explain that hydration should only be according to their level of thirst, per the recommendations of the 3IE-AHCD. Consenting event finishers were included in final analysis. Pre- and post-race anthropometric and biochemical parameters were compared.ResultsThirty-six GTP (33 male) and 94 VGI (88 male) finishers were evaluated. GTP race median fluid intake was 800 ml/h, with 900 ml/h in the VGI race. 83.3% GTPfin and 77.6% VGIfin remained eunatremic (blood sodium 135–145 mmol/L). Only 1/36 GTP and 1/94 VGI participant finished in hyponatremia, both with a sodium level of 134 mmol/L. Fourteen percent of GTP, and 21.2% of VGI participants finished in hypernatremia, with no increase in race completion times. No participating athlete required medical attention, except for musculoskeletal complaints. Pro-BNP and Copeptin levels rose significantly. Changes in copeptin levels did not correlate with changes in plasma osmolality, nor total body water content in impedance analysis.ConclusionsRecommending that athletes' fluid intake in endurance events be a function of their thirst almost entirely prevented development of hyponatremia, without induction of clinically significant hypernatremia, or a negative repercussion on race completion times.

The Management of Hyperthermia and Exercise-Associated Hyponatremia in Low-Resource and Prehospital Settings

Between 2000 and 2016, the number of people exposed to heat waves worldwide increased by around 125 million. As global warming increases, there is growing concern regarding the effect of heat stress on health outcomes, particularly in low- and middle-income tropical countries. The likelihood of developing heat-related injury depends on three factors: an individual, their environment, and their workload. Both exertional hyperthermia and exercise-induced hyponatremia are potentially life-threatening conditions that may develop in environments with increased heat stress. These can present with vague and overlapping symptoms such as confusion, headache, vomiting, and in severe cases, coma. The management of these two conditions is extremely different, and making a correct diagnosis can be challenging, particularly for health-care professionals who are working in low-resource or prehospital settings.

Water: Lifesaving or Fatal?

The animate needs water to survive and human being is not an exception; however, it could be fatal in some circumstances. Quantity and quality of the consumed water as well as time, place, habit, health status, and individual characteristics contribute to daily water need. According to Avicenna's viewpoint, drinking too much water and/ or drinking water without thirst is harmful for the body. Avicenna cited that the person who drink too cold water would see the side effects of this unhealthy habit sooner or later, although may not feel any discomfort or illness at the time. ''Drink to thirst'' is considered a consensus versus to ''drink to max'' in order to prevent exercise-induced hyponatremia.

Hyponatremia

Hyponatremia

Hiponatremia: clasificación y diagnóstico diferencial

Hyponatremia is the most common electrolyte disturbance. This disorder is usually produced by water retention due to the patient's inability to balance water excretion with ingestion of liquids. The present article provides basic information on the physiopathology and epidemiology of hyponatremia in certain contexts such as the ambulatory and hospitalized settings, the geriatric population, exercise-induced hyponatremia, drug-induced hyponatremia and finally hyponatremia observed in some common diseases such as heart failure, liver cirrhosis, pneumonia and HIV infection. The differential diagnosis of hyponatremia should include plasma osmolality, which can be increased, normal or decreased. Most true hyponatremias are grouped in the latter category. If the extracellular volume is decreased, urinary sodium concentrations can be either low or normal with dehydration in the former and water retention in the latter. In hyponatremia with normal extracellular volume, there is free water retention due to a series of stimuli. This entity is seen mainly in hospitalized patients with hypothyroidism or syndrome of inappropriate secretion of antidiuretic hormone. Hyponatremia is underdiagnosed and, more seriously, undertreated, despite numerous studies demonstrating its devastating effects on hospital admissions. The most useful laboratory tests for its diagnosis are urinary sodium concentration, plasma osmolality and urinary osmolality.

Ernährung im Ausdauersport

A well-balanced, adequate dietary intake is essential for both health and athletic performance. Compared to sedentary subjects endurance athletes have higher energy demands and subsequently higher macronutrient requirements. Especially carbohydrate requirement is higher than in non-active individuals (approx. 3.5 g / kg / d) to ensure energy availability during exercise and to replenish glycogen stores after exercise. During weeks of moderately intense exercise a carbohydrate intake of 5-7 g / kg / d is recommended. Glycogen synthesis follows a biphasic manner with an insulin-independent rapid synthesis rate during early regeneration and an insulin-dependent slow synthesis rate in the later regeneration period. Therefore, elite athletes should ingest 1.2-1.5 g / kg / h of carbohydrates with a moderate to high glycemic index immediately after exercise. In some cases high carbohydrate intake may result in a conflict with sports specific requirement of a low body weight. However, a minimum of 5 % body fat for male and 12 % for female athletes is recommended to avoid health issues. During endurance exercise an adequate fluid and electrolyte intake is essential to prevent both dehydration and exercise-induced hyponatremia. Fluid replacement recommendations should be assessed on an individual basis by considering exercise intensity and duration, temperature, sex and body weight. For each hour of exercise the consumption of 400-800 ml containing a minimum of 450 mg sodium per litre is recommended.

Bike Transalp 2008: Liquid Intake and Its Effect on the Body's Fluid Homeostasis in the Course of a Multistage, Cross-Country, MTB Marathon Race in the Central Alps

To investigate the drinking behavior of the participants in a multi-day mountain bike (MTB) cross-country competition, to monitor its effect on the body's fluid compartments and body mass, and to evaluate the prevalence of exercise-associated dysnatremia. Descriptive field study. The Jeantex Bike Transalp Competition 2008 (8 stages; 665.40 km; 21 691 m height). Twenty-five male, amateur MTB cyclists. Reported fluid intake during the race, air temperature. Changes in body mass and body composition from pre to post race and throughout the competition week, serum sodium concentration at finish line of stages 5 and 6. Mean (+ or - SD) hourly fluid intake during the race correlated with air temperature (r = 0.868, P < .05) and ranged between 494 + or - 191 mL/h and 754 + or - 254 mL/h. In absence of exercise-induced hyponatremia (EAH) cases, we report 5 and 4 cases of asymptomatic post-race hypernatremia, on days 5 and 6, respectively. When related to race time and body mass, the liquid intake during the race (in mL x kg(-1) x h(-1)) correlated with post-race serum sodium concentration (stage 5: r = -0.463, P < .05, n = 24; stage 6: r = -0.589, P < .01, n = 23); no correlation was found between the change in body mass from pre to post race and serum sodium concentration at finish line. Ad libitum fluid consumption during competition was spontaneously adjusted to the unsettled weather conditions in the course of the 2008 "Bike Transalp." The inverse linear relationship between hourly fluid intake and post-race serum sodium concentrations suggests underdrinking to be one contributing factor to the high reported incidence of hypernatremia in the absence of EAH. Experimental studies are requested to confirm this hypothesis and to further examine the pathogenesis of exercise-associated dysnatremia. In this setting, body mass monitoring was not an accurate instrument to control body fluid homeostasis.

Exercise-Associated Hyponatremia Masquerading as Acute Mountain Sickness: Are We Missing the Diagnosis?

Exercise-Associated Hyponatremia Masquerading as Acute Mountain Sickness: Are We Missing the Diagnosis?

An unusual cause of exercise‐induced hyponatremia

A case of exercise-induced hyponatremia due to an unusual cause is presented.

Exercise-induced hyponatremia: causes, risks, prevention, and management.

Exercise-induced hyponatremia is most commonly associated with prolonged exertion during sustained, high-intensity endurance activities such as marathons or triathlons. In most cases, exercise-induced hyponatremia is attributable to excess free water intake, which fails to replete the sometimes massive sodium losses that result from sweating. The risk of hyponatremia can be lowered by strategies to ensure fluid balance during exercise by maintaining the proper volume and type of fluid intake. Treatment of exercise-induced hyponatremia is based on whether the patient is volume-depleted, euvolemic, or fluid-overloaded. Because therapy must be tailored to volume status, physicians must make this determination before initiating therapy. If hyponatremia is life-threatening, hypertonic saline may be warranted to increase sodium in the extracellular fluid compartment and restore the natural balance.

Moderate Exercise-Induced Hyponatremia

Moderate Exercise-Induced Hyponatremia

Exercise-induced hyponatremia in ultradistance triathletes is caused by inappropriate fluid retention.

To study fluid and sodium balance during overnight recovery following an ultradistance triathlon in hyponatremic athletes compared with normonatremic controls. CASE CONTROL STUDY: Prospective descriptive study. 1997 New Zealand Ironman Triathlon (3.8 Km swim, 180 Km cycle, 42.2 Km run). Seven athletes ("subjects") hospitalized with hyponatremia (median sodium [Na] = 128 mmol L(-1)). Data were compared with measurements from 11 normonatremic race finishers ("controls") (median sodium = 141 mmol L(-1)). None. Athletes were weighed prior to, immediately after, and on the morning after, the race. Blood was drawn for sodium, hemoglobin, and hematocrit immediately after the race and the following morning. Plasma concentrations of arginine-vasopressin (AVP) were also measured post race. Subjects were significantly smaller than controls (62.5 vs. 72.0 Kg) and lost less weight during the race than controls (median -0.5% vs. -3.9%, p = 0.002) but more weight than controls during recovery (-4.4% vs. -0.8%, p 0.002). Subjects excreted a median fluid excess during recovery (1,346 ml): controls had a median fluid deficit (521 ml) (p = 0.009). Estimated median sodium deficit was the same in subjects and controls (88 vs. 38 mmol L(-1), p = 0.25). Median AVP was significantly lower in subjects than in controls. Plasma volume fell during recovery in subjects (-5.9%, p = 0.016) but rose in controls (0.76%, p = NS). Triathletes with symptomatic hyponatremia following very prolonged exercise have abnormal fluid retention including an increased extracellular volume, but without evidence for large sodium losses. Such fluid retention is not associated with elevated plasma AVP concentrations.

Drowning in the desert: Exercise-induced hyponatremia at the Grand Canyon

Drowning in the desert: Exercise-induced hyponatremia at the Grand Canyon

This Month in the Journal

This Month in the Journal

Evaluation of renal function and fluid homeostasis during recovery from exercise-induced hyponatremia

Renal function including fluid and electrolyte balance was studied during recovery in eight subjects who developed symptomatic hyponatremia (HN; plasma sodium concentration less than 130 mM) during an 88-km ultramarathon footrace and compared with results for normonatremic runners [NN; n = 18, mean postrace plasma sodium concentration, 138.2 +/- 1.2 (SE) mM]. Estimated fluid intake during the race for HN was 12.5 +/- 1.6 (SE) liters over 9 h 41 min (+/- 28 min). HN excreted a net fluid excess of 2.95 +/- 0.56 (range 1.2-5.9) liters compared with a fluid deficit of 2.7 +/- 0.3% body weight in NN. The sodium deficit was 153 +/- 35 mmol in HN and 187 +/- 37 mmol in NN. Despite the fluid overload, plasma volume was decreased by 24.1 +/- 5.0% in HN compared with 8.2 +/- 2.6% in NN. Serum renin activity (5.1 +/- 2.0 ng.ml-1.h-1), aldosterone concentrations (410 +/- 34 ng/l), creatinine clearances (174.8 +/- 28.2 ml/min), and urine output (6.4 +/- 1.0 ml/min) were markedly elevated in HN during recovery. Thus the hyponatremia of exercise results from fluid retention in subjects who ingest abnormally large fluid volumes during prolonged exercise.

Dehydration and hyponatremia during triathlons

In ultraendurance triathlons, dehydration and electrolyte balance are important factors in race completion and level of performance. Dehydration is the most common reason for a triathlete in the Hawaii Ironman Triathlon to need medical assistance. Hyponatremia is the predominant electrolyte disturbance. We have previously described exercise-induced hyponatremia and documented its incidence as a function of race length and state of hydration. This syndrome, dehydration plus hyponatremia, is extremely rare in races lasting less than 4 h but becomes common in races lasting longer than 8 h. Recommendations are made to help ultraendurance athletes understand and maintain proper fluid and electrolyte balance.