Prevalence Of Exercise-associated Hyponatremia Research Articles

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

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. 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. 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. 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.

Statement of the 3rd International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015

The 3rd International Exercise-Associated Hyponatremia (EAH) Consensus Development Conference convened in Carlsbad, California, in February 2015, with a panel of 17 international experts. The delegates represented four countries and nine...

Physiopathological, Epidemiological, Clinical and Therapeutic Aspects of Exercise-Associated Hyponatremia.

Exercise-associated hyponatremia (EAH) is dilutional hyponatremia, a variant of inappropriate antidiuretic hormone secretion (SIADH), characterized by a plasma concentration of sodium lower than 135 mEq/L. The prevalence of EAH is common in endurance (<6 hours) and ultra-endurance events (>6 hours in duration), in which both athletes and medical providers need to be aware of risk factors, symptom presentation, and management. The development of EAH is a combination of excessive water intake, inadequate suppression of the secretion of the antidiuretic hormone (ADH) (due to non osmotic stimuli), long race duration, and very high or very low ambient temperatures. Additional risk factors include female gender, slower race times, and use of nonsteroidal anti-inflammatory drugs. Signs and symptoms of EAH include nausea, vomiting, confusion, headache and seizures; it may result in severe clinical conditions associated with pulmonary and cerebral edema, respiratory failure and death. A rapid diagnosis and appropriate treatment with a hypertonic saline solution is essential in the severe form to ensure a positive outcome.

The prevalence of exercise-associated hyponatremia in 24-hour ultra-mountain bikers, 24-hour ultra-runners and multi-stage ultra-mountain bikers in the Czech Republic.

BackgroundTo assess the prevalence of exercise-associated hyponatremia (EAH) in two 24-hour mountain bike (MTB) (R1,R2), one 24-hour running (R3) and one multi-stage MTB (R4) races held in the Czech Republic in a cluster of four cross-sectional studies.MethodsIn 27 ultra-mountain bikers (ultra-MTBers), 12 ultra-runners, and 14 multi-stage MTBers, fluid intake, changes (Δ) in body mass, hematocrit, plasma volume, plasma [Na+], plasma [K+], plasma osmolality, urine [Na+], urine [K+], urine specific gravity, urine osmolality, K+/Na+ ratio in urine, transtubular potassium gradient and glomerular filtration rate were measured and calculated. The use of non-steroidal anti-inflammatory drugs and symptoms of EAH were recorded using post-race questionnaires.ResultsOf the 53 finishers, three (5.7%) developed post-race EAH, thereof one (3.7%) ultra-MTBer, one (8.3%) ultra-runner and one (7.1%) multi-stage MTBer. Plasma [Na+] decreased significantly (p < 0.001) only in R4. Urine osmolality (R1, R3, R4 p < 0.001; R2 p < 0.05) and glomerular filtration rate (p < 0.001) increased, and body mass decreased in all races (p < 0.05). Δ body mass was inversely related to the number of kilometers achieved (p < 0.001) in R2 where better ultra-MTBers tended to lose more weight. Δ body mass (p < 0.001) and %Δ body mass (p = 0.05) were positively related to lower post-race plasma [Na+] in R3 that was associated with increased loss in body mass. Fluid intake was positively related to race performance in R1 and R2 (R1: p = 0.04; R2: p = 0.01) where ultra-MTBers in R1 and R2 who drank more finished ahead of those who drank less. Post-race plasma [Na+] was negatively associated with race performance in ultra-MTBers in R2 (p < 0.05), similarly ultra-runners in R3 (p < 0.05) where finishers with more kilometres had lower post-race plasma [Na+].ConclusionsThe prevalence of EAH in the Czech Republic was no higher compared to existing reports on ultra-endurance athletes in other countries. Lower plasma [Na+] and development of EAH may be attributed to overdrinking, a pituitary secretion of vasopressin, an impaired mobilization of osmotically inactive sodium stores, and/or an inappropriate inactivation of osmotically active sodium.

Higher Prevalence of Exercise-Associated Hyponatremia in Triple Iron Ultra-Triathletes Than Reported for Ironman Triathletes

"In a recent study of male and female ultra-marathoners in a 161-km ultra-marathon, the prevalence of exercise-associated hyponatremia (EAH) was higher than reported for marathoners. Regarding triathletes, the prevalence of EAH has been investigated in Ironman triathletes, but not in Triple Iron ultra-triathletes. The aim of this study was to investigate the prevalence of EAH in male ultra-triathletes competing in a Triple Iron ultra-triathlon over 11.4 km swimming, 540 km cycling, and 126.6 km running. Changes in body mass, fat mass, skeletal muscle mass, total body water, haematocrit, plasma volume, plasma sodium concentration ([Na ⁺ ]) and urine specific gravity were determined in 31 male athletes with (means ± standard deviation) 42.1 ± 8.1 years of age, 77.0 ± 7.0 kg body mass, 1.78 ± 0.06 m body height and a BMI of 24.3 ± 1.7 kg/m² in the 'Triple Iron Triathlon Germany'. Of the 31 finishers, eight athletes (26%) developed asymptomatic EAH. Body mass, fat mass, skeletal muscle mass, and haematocrit decreased, plasma volume increased ( P < 0.05), plasma [Na ⁺], total body water and urine specific gravity remained stable. The decrease in body mass was related to both the decrease in fat mass and skeletal muscle mass ( P < 0.05), but was not related to overall race time, the change in plasma [Na ⁺ ], post-race plasma [Na ⁺ ], or urine specific gravity. The prevalence of EAH was higher in these Triple Iron ultra-triathletes compared to existing reports on Ironman triathletes. Body fluid homeostasis remained stable in these ultra-triathletes although body mass decreased."

Low prevalence of exercise-associated hyponatremia in male 100km ultra-marathon runners in Switzerland

Low prevalence of exercise-associated hyponatremia in male 100km ultra-marathon runners in Switzerland

No Case of Exercise-Associated Hyponatremia in Male Ultra-Endurance Mountain Bikers in the ‘Swiss Bike Masters’

Exercise-associated hyponatremia (EAH) has mainly been investigated in runners and triathletes. In mountain bikers, EAH was studied in two multi-stage races, but not in a single stage race. The aim of this study was to investigate the prevalence of EAH in a single-stage mountain bike ultra-marathon. In the 'Swiss Bike Masters' over 120 km with a climb of ~ 5,000 m in altitude, we determined pre and post race body mass, hematocrit, plasma sodium concentration ([Na⁺]), and urinary specific gravity in 37 cyclists. Athletes recorded their fluid intake while racing. No athlete developed EAH. The cyclists drank on average (means ± SD) 0.7 ± 0.2 l/h. Fluid intake was significantly and negatively related to race time (r = -0.41, P < 0.05), but showed no association with post race plasma [Na⁺], the change in plasma [Na⁺], post race body mass, or the change in body mass. The athletes lost 1.4 kg body mass (P < 0.05), plasma [Na⁺] decreased by 0.7% (P < 0.05), plasma volume increased by 1.4% and urinary specific gravity increased by 0.4% (P < 0.05). The change in body mass was neither related to post race plasma [Na⁺] nor to the change in plasma [Na⁺]. The decrease in plasma [Na⁺] was not related to fluid intake. The change in plasma [Na⁺] was related to post race plasma [Na⁺] (r = 0.40, P < 0.01). Ad libitum fluid intake showed no case of EAH in a single-stage mountain bike ultra-marathon. In contrast to previous findings, the faster athletes drank more than the slower ones.

Maintained Serum Sodium in Male Ultra-Marathoners – The Role of Fluid Intake, Vasopressin, and Aldosterone in Fluid and Electrolyte Regulation

Exercise-associated hyponatremia (EAH) is a well know electrolyte disorder in endurance athletes. Although fluid overload is the most like etiology, recent studies, however, argued whether EAH is a disorder of vasopressin secretion. The aims of the present study were to investigate (i) the prevalence of EAH in male ultra-marathoners and (ii) whether fluid intake, aldosterone or vasopressin, as measured by copeptin, were associated with post-race serum sodium concentration ([Na+]). In 50 male ultra-marathoners in a 100 km ultra-marathon, serum [Na+], aldosterone, copeptin, serum and urine osmolality, and body mass were measured pre- and post-race. Fluid intake, renal function parameters and urine excretion were measured. No athlete developed EAH. Copeptin and aldosterone increased; a significant correlation was found between the change in copeptin and the change in serum [Na+], no correlation was found between aldosterone and serum [Na+]. Serum [Na+] increased by 1.6%; body mass decreased by 1.9 kg. The change in serum [Na+] and body mass correlated significantly and negatively. The fluid intake of ~ 0.58 l/h was positively related to the change in body mass and negatively to both post-race serum [Na+] and the change in serum [Na+]. We conclude that serum [Na+] was maintained by both the mechanisms of fluid intake and the hormonal regulation of vasopressin.

Higher prevalence of exercise-associated hyponatremia in female than in male open-water ultra-endurance swimmers: the ‘Marathon-Swim’ in Lake Zurich

We investigated the prevalence of exercise-associated hyponatremia (EAH) in 25 male and 11 female open-water ultra-endurance swimmers participating in the 'Marathon-Swim' in Lake Zurich, Switzerland, covering a distance of 26.4 km. Changes in body mass, fat mass, skeletal muscle mass, total body water, urine specific gravity, plasma sodium concentration [Na(+)] and haematocrit were determined. Two males (8%) and four females (36%) developed EAH where one female was symptomatic with plasma sodium [Na(+)] of 127 mmol/L. Body mass and plasma [Na(+)] decreased (p < 0.05). The changes in body mass correlated in both male and female swimmers to post-race plasma [Na(+)] (r = -0.67, p = 0.0002 and r = -0.80, p = 0.0034, respectively) and changes in plasma [Na(+)] (r = -0.68, p = 0.0002 and r = -0.79, p = 0.0039, respectively). Fluid intake was neither associated with changes in body mass, post-race plasma [Na(+)] or the change in plasma [Na(+)]. Sodium intake showed no association with either the changes in plasma [Na(+)] or post-race plasma [Na(+)]. We concluded that the prevalence of EAH was greater in female than in male open-water ultra-endurance swimmers.

Prevalence of Exercise-Associated Hyponatremia in Male Ultraendurance Athletes

The prevalence of exercise-associated hyponatremia (EAH) has mainly been investigated in marathoners and Ironman triathletes. The aim of this study was to investigate the prevalence of EAH in male ultraendurance athletes in other disciplines, such as ultraswimming, ultracycling, and ultramarathon running. Observational field study. "Marathon Swim" in Lake Zurich, the "Swiss Cycling Marathon," the "Swiss Bike Masters," the "100-km Lauf Biel," and the "Swiss Jura Marathon." Fifteen ultraswimmers, 28 ultra-road cyclists, 37 ultra-mountain bikers, 95 ultramarathoners, and 25 mountain ultramarathoners. Changes in body mass, plasma sodium, urinary specific gravity, and hematocrit were measured. The athletes recorded their intake of fluids. Two swimmers (13%), 3 road cyclists (10.7%), no mountain bikers (0%), 5 ultramarathoners (5%), and 2 mountain ultramarathoners (8%) developed EAH. In the mountain bikers (r = -0.41) and the 100-km ultramarathoners (r = -0.52), fluid intake was significantly and negatively related to race time. In the mountain ultramarathoners, fluid consumption increased during the race. The prevalence of EAH was no higher in ultraendurance athletes compared with existing reports on marathoners and Ironman triathletes. Of the 200 investigated ultraendurance athletes, 12 finishers (6%) developed EAH.

No Exercise-Associated Hyponatremia Found in an Observational Field Study of Male Ultra-Marathoners Participating in a 24-Hour Ultra-Run

Aims: In a recent study of male ultra-marathoners who participated in a 161-km ultra-run, the prevalence of exercise-associated hyponatremia (EAH) was reported to be 50%, which is a considerably higher percentage than that seen in marathoners. We investigated the prevalence of EAH in male ultra-marathoners competing in a 24-hour run held in Basel, Switzerland. Body weight, hematocrit levels, plasma volume, plasma sodium concentration, urine specific gravity, and fluid intake were recorded in 15 male ultra-marathoners (mean age ± standard deviation [SD], 46.7 [5.8] years; plasma sodium, 71.1 [6.8] kg; height, 1.76 [0.07] m; body weight, 23.1 [1.84] kg/m2). Plasma sodium was measured at 135.3 (2.8) mmol/L before the race and remained unchanged at 135.4 (3.6) mmol/L after the race. The competitors consumed a total of 15.1 (5.1) L during the race, equal to 0.62 (0.21) L/hour. Fluid intake correlated to the mean running speed (r = −0.87; P = 0.0001). Body weight decreased significantly (P = 0.0009) by 2.2 kg. Hematocrit remained unchanged, and urine specific gravity increased significantly (P = 0.0005). Plasma volume increased by 4.9% (15.8%). Changes in body weight showed no association with post-race plasma sodium. The normal resting value should be 140 mmol/L so that a decrease of 5 mmol/L is described as EAH. Because the starting plasma sodium in this study was 135 mmol/L, it is not possible to define EAH as a value that is < 135 mmol/L. Instead, the correct definition should be a plasma sodium concentration of 130 mmol/L (ie, 5mmol/L below the normal resting value). Following this definition, it was determined that no athlete developed EAH in this 24-hour run.

Low prevalence of exercise-associated hyponatremia in male 100 km ultra-marathon runners in Switzerland

We investigated the prevalence of exercise-associated hyponatremia (EAH) in 145 male ultra-marathoners at the '100-km ultra-run' in Biel, Switzerland. Changes in body mass, urinary specific gravity, haemoglobin, haematocrit, plasma [Na(+)], and plasma volume were determined. Seven runners (4.8%) developed asymptomatic EAH. Body mass, haematocrit and haemoglobin decreased, plasma [Na(+)] remained unchanged and plasma volume increased. Δ body mass correlated with both post race plasma [Na(+)] and Δ plasma [Na(+)]. Δ plasma volume was associated with post race plasma [Na(+)]. The athletes consumed 0.65 (0.30) L/h; fluid intake correlated significantly and negatively (r = -0.50, p < 0.0001) to race time. Fluid intake was neither associated with post race plasma [Na(+)] nor with Δ plasma [Na(+)], but was related to Δ body mass. To conclude, the prevalence of EAH was low at ~5% in these male 100 km ultra-marathoners. EAH was asymptomatic and would not have been detected without the measurement of plasma [Na(+)].

Maintained total body water content and serum sodium concentrations despite body mass loss in female ultra-runners drinking ad libitum during a 100 km race.

We investigated in 11 female ultra-runners during a 100 km ultra-run, the association between fluid intake and prevalence of exercise-associated hyponatremia in a cross-sectional study. Athletes drank ad libitum and recorded their fluid intake. They competed at 8.0 (1.0) km/h and finished within 762 (91) min. Fluid intake was 4.1 (1.3) L during the race, equal to 0.3 (0.1) L/h. Body mass decreased by 1.5 kg (p< 0.01); pre race body mass was related to speed in the race (r = -0.78, p< 0.05); and change (Delta) in body mass was not associated with speed in the race. Change in body mass was positively (r = 0.70; p< 0.05), and Delta urinary specific gravity negatively (r = -0.67; p< 0.05), correlated to Delta percent total body water. Changes in body mass were not related to fluid intake during the race. Fluid intake was not correlated to running speed and showed no association with either Delta percent total body water nor Delta [Na] in plasma. Fluid intake showed no relationship with both Delta haematocrit and Delta plasma volume. No exercise-associated hyponatremia occurred. Female ultra- runners consuming fluids ad libitum during the race experienced no fluid overload, and ad libitum drinking protects against exercise-associated hyponatremia. The reported higher incidence of exercise-associated hyponatremia in women is not really a gender effect but due to women being more prone to overdrink.