- MeSH
- Acidosis metabolism MeSH
- Adult MeSH
- Adaptation, Physiological MeSH
- Insulin blood metabolism MeSH
- Humans MeSH
- Adolescent MeSH
- Calcium Metabolism Disorders etiology physiopathology MeSH
- Growth Hormone blood metabolism MeSH
- Exercise Test MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Adolescent MeSH
- Publication type
- Comparative Study MeSH
Exercise-associated hyponatremia (EAH) is defined as a plasma sodium concentration of <135 mmol/L during or after endurance and ultra-endurance performance and was first described by Timothy Noakes when observed in ultra-marathoners competing in the Comrades Marathon in South Africa in the mid-1980s. It is well-established that a decrease in plasma sodium concentration <135 mmol/L occurs with excessive fluid intake. Clinically, a mild hyponatremia will lead to no or very unspecific symptoms. A pronounced hyponatremia (<120 mmol/L) will lead to central nervous symptoms due to cerebral edema, and respiratory failure can lead to death when plasma sodium concentration reaches values of <110-115 mmol/L. The objective of this narrative review is to present new findings about the aspects of sex, race location, sports discipline, and length of performance. The prevalence of EAH depends on the duration of an endurance performance (i.e., low in marathon running, high to very high in ultra-marathon running), the sports discipline (i.e., rather rare in cycling, more frequent in running and triathlon, and very frequent in swimming), sex (i.e., increased in women with several reported deaths), the ambient temperature (i.e., very high in hot temperatures) and the country where competition takes place (i.e., very common in the USA, very little in Europe, practically never in Africa, Asia, and Oceania). A possible explanation for the increased prevalence of EAH in women could be the so-called Varon-Ayus syndrome with severe hyponatremia, lung and cerebral edema, which was first observed in marathon runners. Regarding the race location, races in Europe seemed to be held under rather moderate conditions whereas races held in the USA were often performed under thermally stressing conditions (i.e., greater heat or greater cold).
- MeSH
- Exercise physiology MeSH
- Physical Endurance physiology MeSH
- Hyponatremia etiology physiopathology MeSH
- Humans MeSH
- Prevalence MeSH
- Racial Groups statistics & numerical data MeSH
- Risk Factors MeSH
- Sex Factors * MeSH
- Sodium analysis blood MeSH
- Sports physiology statistics & numerical data MeSH
- Temperature MeSH
- Water-Electrolyte Balance physiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
- MeSH
- Adult MeSH
- Humans MeSH
- Motor Activity MeSH
- Physical Fitness MeSH
- Exercise Test MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
Critical power represents an important parameter of aerobic function and is the highest average effort that can be sustained for a period of time without fatigue. Critical power is determined mainly in the laboratory. Many different approaches have been applied in testing methods, and it is a difficult task to determine which testing protocol it the most suitable. This review aims to evaluate all possible tests on bicycle ergometers or bicycles used to estimate critical power and to compare them. A literature search was conducted in four databases (PubMed, Scopus, SPORTDiscus, and Web of Science) published from 2012 to 2022 and followed the PRISMA guidelines to process the review. Twenty-one articles met the eligibility criteria: records with trained or experienced endurance athletes (adults > 18), bicycle ergometer, a description of the testing protocol, and comparison of the tests. We found that the most widely used tests were the 3-min all-out tests set in a linear mode and the traditional protocol time to exhaustion. Some other alternatives could have been used but were not as regular. To summarize, the testing methods offered two main approaches in the laboratory (time to exhaustion test andthe 3-min all-out test with different protocols) and approach in the field, which is not yet completely standardized.
Exercise-Associated Hyponatremia in Endurance Performance Abstract. Exercise-associated hyponatremia is defined as a plasma sodium concentration of <135 mmol/l and was first described by Timothy Noakes at the Comrades Marathon in South Africa in the mid-1980s. A decrease in plasma sodium <135 mmol/l occurs with excessive fluid intake. Risk factors include long to very long endurance performance, extreme climatic conditions, female gender and competitions in the USA. Regarding its prevalence by sport, exercise-associated hyponatraemia tends to occur while swimming and running, but rarely when cycling. While mild exercise-associated hyponatremia does not lead to clinical symptoms, severe hyponatremia due to cerebral edema can lead to neurological deficits and even death. The best prevention of exercise-associated hyponatremia is the reduction of fluid intake during exercise.
- MeSH
- Running * MeSH
- Physical Endurance * MeSH
- Hyponatremia * MeSH
- Humans MeSH
- Nutritional Status MeSH
- Swimming MeSH
- Sodium MeSH
- Check Tag
- Humans MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
The monitoring of body mass (BM), plasma sodium concentration ([Na⁺]) and urinary specific gravity (Usg) are commonly used to help detect and prevent over- or dehydration in endurance athletes. We investigated pre-and post-race hydration status in 113 amateur 24-h ultra-runners, 100-km ultra-runners, multi-stage mountain bikers and 24-h mountain bikers, which drank ad libitum without any intervention and compared results of hyponatremic and non-hyponatremic finishers. On average, pre-race plasma [Na⁺] and both pre- and post-race levels of Usg and BM were not significantly different between both groups. However, nearly 86% of the post-race hyponatremic (exercise-associated hyponatremia, EAH) and 68% of the normonatremic (non-EAH) ultra-athletes probably drank prior the race greater volumes than their thirst dictated regarding to individual pre-race Usg levels. Fluid intake during the race was equal and was not related to plasma [Na⁺], Usg or BM changes. A significant decrease in post-race plasma [Na⁺], BM and an increasement in post-race Usg was observed in EAH and non-EAH finishers. Moreover, pre-race plasma [Na⁺] was inversely associated with post-race percentage change in plasma [Na⁺], and pre-race Usg and urinary [Na⁺] with percentage change in Usg in both groups with and without post-race EAH. Thirteen (11.5%) finishers developed post-race EAH (plasma [Na⁺] < 135 mM). The incidence of EAH in ultra-endurance athletes competing in the Czech Republic was higher than reported previously.
- MeSH
- Running * MeSH
- Bicycling * MeSH
- Physical Endurance * MeSH
- Hyponatremia epidemiology metabolism MeSH
- Incidence MeSH
- Middle Aged MeSH
- Humans MeSH
- Drinking MeSH
- Sodium blood urine MeSH
- Athletes MeSH
- Body Weight MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Czech Republic epidemiology MeSH
Aging leads to a decrease in muscle function, mass, and strength in skeletal muscle of animals and humans. The transcriptome identified activation of the JAK/STAT pathway, a pathway that is associated with skeletal muscle atrophy, and endurance training has a significant effect on improving sarcopenia; however, the exact mechanism still requires further study. We investigated the effect of endurance training on sarcopenia. Six-month-old male SAMR1 mice were used as a young control group (group C), and the same month-old male SAMP8 mice were divided into an exercise group (group E) and a model group (group M). A 3-month running exercise intervention was performed on group E, and the other two groups were kept normally. Aging caused significant signs of sarcopenia in the SAMP8 mice, and endurance training effectively improved muscle function, muscle mass, and muscle strength in the SAMP8 mice. The expression of JAK2/STAT3 pathway factor was decreased in group E compared with group M, and the expression of SOCS3, the target gene of STAT3, and NR1D1, an atrophy-related factor, was significantly increased. Endurance training significantly improved the phenotypes associated with sarcopenia, and the JAK2/STAT3 pathway is a possible mechanism for the improvement of sarcopenia by endurance training, while NR1D1 may be its potential target. Keywords: Sarcopenia, Endurance training, Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3), Nuclear receptor subfamily 1, group D member 1 (Nr1d1).
- MeSH
- Janus Kinase 2 * metabolism MeSH
- Physical Conditioning, Animal * physiology MeSH
- Muscle, Skeletal metabolism MeSH
- Mice MeSH
- Sarcopenia * metabolism prevention & control therapy MeSH
- Signal Transduction * MeSH
- Aging metabolism MeSH
- STAT3 Transcription Factor * metabolism MeSH
- Endurance Training * MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
A The incidence of exercise-associated hyponatremia (EAH) is higher in women than in men. We present three cases of a very mild post-race EAH in female winners of three 24-h ultra races in various weather conditions and disciplines with post-race plasma sodium [Na⁺] levels of 134 mM (Case 1), 133 mM (Case 2) and 134 mM (Case 3). Moreover, Case 1 and Case 2 showed elevated creatine kinase concentrations of >10,000 U/l with an absence of renal function abnormality. The common characteristics were female sex, veteran recreational category, long race experience in the particular sports discipline, excellent race performance, similar total weekly training hours and the presence of luteal phase of the menstrual cycle during the race. Hematocrit and hemoglobin decreased and post-race K⁺/Na⁺ ratio in urine increased in all three cases. In addition, an increased body mass and a decreased urine specific gravity and urine osmolality suggested over-drinking in Case 1. A decrease in the glomerular filtration rate and creatine clearance accompanied by an increase in urine [Na⁺] may contribute to fluid overload in Cases 2 and 3. Furthermore, urine osmolality reached a level indicating antidiuretic hormone secretion in all the present cases. Therefore, we recommend that race medical personnel should not forget to look for EAH even in fast and experienced female athletes and during races in different environmental conditions.
- MeSH
- Exercise physiology MeSH
- Adult MeSH
- Physical Endurance * MeSH
- Hyponatremia etiology MeSH
- Middle Aged MeSH
- Humans MeSH
- Weather * MeSH
- Sodium blood MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Twenty-eight endurance-trained males aged 31.1 ± 10.2 years (body mass [BM] 81.9 ± 9.0 kg) completed this randomized double-blind placebo (PLA)-controlled crossover study investigating the effect of 12-week Colostrum Bovinum (COL) supplementation (25gCOL·day-1) on aerobic fitness and capacity, time to exhaustion, BM and body composition (BC), and blood lactate concentration. There were four main-before/after supplementation study visits (COLPRE and COLPOST; PLAPRE, and PLAPOST). During study visits, BM and BC evaluation, incremental rowing test (IRT) to exhaustion, and evaluation of resting (REST) and post-exercise (POST-IRT) blood lactate concentration were performed. COL, but not PLA supplementation, significantly increased (p < 0.05) time to ventilatory threshold (TVT). Moreover, the implemented treatments had large (mL·min-1) and moderate (mL·min-1·kg-1) effects on oxygen uptake at VT (VO2VT), as well as moderate effect on power output at VT (PVT; W·kg-1) with the highest values observed at COLPOST visit. Neither significant influence of COL supplementation on time to exhaustion (TEXH) in IRT, BM, and BC on blood lactate was observed. Importantly, there were significantly (p < 0.05) higher increases in VO2VT (mL·min-1 and mL·min-1·kg-1) after COL compared to PLA supplementation. In summary, COL supplementation resulted in a favorable increase in TVT, and tended to improve some of the evaluated threshold indicators, namely VO2VT and PVT in endurance-trained male athletes during IRT. Therefore, COL supplementation may be considered as a support to improve aerobic fitness and capacity in endurance-trained males; however, supplementation strategy must be personalized and properly incorporated into the individual training. TRIAL REGISTRATION: The study protocol was registered at ClinicalTrials.gov (NCT06390670).
- MeSH
- Adult MeSH
- Double-Blind Method MeSH
- Physical Endurance * MeSH
- Cross-Over Studies MeSH
- Colostrum * MeSH
- Lactic Acid blood MeSH
- Humans MeSH
- Young Adult MeSH
- Dietary Supplements * MeSH
- Body Composition * MeSH
- Oxygen Consumption MeSH
- Endurance Training * MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Publication type
- Journal Article MeSH
- Randomized Controlled Trial MeSH
