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14 pages, 513 KiB

Open AccessArticle

Pre-Competition Weight Loss Models in Taekwondo: Identification, Characteristics and Risk of Dehydration

by Katarzyna Janiszewska and Katarzyna E. Przybyłowicz

Nutrients 2020, 12(9), 2793; https://doi.org/10.3390/nu12092793 - 12 Sep 2020

Cited by 12 | Viewed by 5245

Athletes use different combinations of weight loss methods during competition preparation. The aim of this study was to identify and characterize pre-competition weight loss models, which describe these combinations. The second aim was to determine if any existing model pose a higher risk [...] Read more.

Athletes use different combinations of weight loss methods during competition preparation. The aim of this study was to identify and characterize pre-competition weight loss models, which describe these combinations. The second aim was to determine if any existing model pose a higher risk of severe dehydration and whether any of the models could be continued as a lower-risk option. The third aim was to explore whether athletes who used different weight management strategies could be differentiated based on age, sex, training experience or anthropometric parameters. Study participants were randomly selected from Olympic taekwondo competitors and 192 athletes were enrolled. Active (47% weight-reducing athletes), passive (31%) and extreme (22%) models have been described. In the extreme model, athletes combined the highest number of different weight loss methods (3.9 ± 0.9 methods vs. 2.4 ± 0.9 in active and 1.5 ± 0.6 in passive), reduced significantly more body mass than others (6.7 ± 3.5% body mass vs. 4.3 ± 1.9% and 4.5 ± 2.4%; p < 0.01) and all of them used methods with the highest risk of severe dehydration. The active and passive models could be continued as a lower-risk option, if athletes do not combine dehydrating methods and do not prolong the low energy availability phase. The extreme model carried the highest risk of severe dehydration. Every fifth weight-reducing taekwondo athlete may have been exposed to the adverse effects of acute weight loss. Taekwondo athletes, regardless of age, sex, training experience and anthropometric parameters, lose weight before the competition and those characteristics do not differentiate them between models. Full article

(This article belongs to the Special Issue Hydration and Nutrition Considerations for Sports and Physical Activity)

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22 pages, 1415 KiB

Open AccessArticle

Pathophysiological Mechanisms by which Heat Stress Potentially Induces Kidney Inflammation and Chronic Kidney Disease in Sugarcane Workers

by Erik Hansson, Jason Glaser, Kristina Jakobsson, Ilana Weiss, Catarina Wesseling, Rebekah A. I. Lucas, Jason Lee Kai Wei, Ulf Ekström, Julia Wijkström, Theo Bodin, Richard J. Johnson and David H. Wegman

Nutrients 2020, 12(6), 1639; https://doi.org/10.3390/nu12061639 - 02 Jun 2020

Cited by 54 | Viewed by 8747

Abstract

Background: Chronic kidney disease of non-traditional origin (CKDnt) is common among Mesoamerican sugarcane workers. Recurrent heat stress and dehydration is a leading hypothesis. Evidence indicate a key role of inflammation. Methods: Starting in sports and heat pathophysiology literature, we develop a theoretical framework [...] Read more.

Background: Chronic kidney disease of non-traditional origin (CKDnt) is common among Mesoamerican sugarcane workers. Recurrent heat stress and dehydration is a leading hypothesis. Evidence indicate a key role of inflammation. Methods: Starting in sports and heat pathophysiology literature, we develop a theoretical framework of how strenuous work in heat could induce kidney inflammation. We describe the release of pro-inflammatory substances from a leaky gut and/or injured muscle, alone or in combination with tubular fructose and uric acid, aggravation by reduced renal blood flow and increased tubular metabolic demands. Then, we analyze longitudinal data from >800 sugarcane cutters followed across harvest and review the CKDnt literature to assess empirical support of the theoretical framework. Results: Inflammation (CRP elevation and fever) and hyperuricemia was tightly linked to kidney injury. Rehydrating with sugary liquids and NSAID intake increased the risk of kidney injury, whereas electrolyte solution consumption was protective. Hypokalemia and hypomagnesemia were associated with kidney injury. Discussion: Heat stress, muscle injury, reduced renal blood flow and fructose metabolism may induce kidney inflammation, the successful resolution of which may be impaired by daily repeating pro-inflammatory triggers. We outline further descriptive, experimental and intervention studies addressing the factors identified in this study. Full article

(This article belongs to the Special Issue Hydration and Nutrition Considerations for Sports and Physical Activity)

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16 pages, 2114 KiB

Open AccessArticle

Hydration Efficacy of a Milk Permeate-Based Oral Hydration Solution

by Craig W. Berry, S. Tony Wolf, Bob Murray and W. Larry Kenney

Nutrients 2020, 12(5), 1502; https://doi.org/10.3390/nu12051502 - 21 May 2020

Cited by 13 | Viewed by 5597

Abstract

Milk permeate is an electrolyte-rich, protein- and fat-free liquid with a similar carbohydrate and mineral content to that of milk. Its hydration efficacy has not been examined. The beverage hydration index (BHI) has been used to compare various beverages to water in terms [...] Read more.

Milk permeate is an electrolyte-rich, protein- and fat-free liquid with a similar carbohydrate and mineral content to that of milk. Its hydration efficacy has not been examined. The beverage hydration index (BHI) has been used to compare various beverages to water in terms of post-ingestion fluid balance and retention. Our purpose was to compare the BHI (and related physiological responses) of a novel milk permeate solution (MPS) to that of water and a traditional carbohydrate–electrolyte solution (CES). Over three visits, 12 young subjects consumed 1 L of water, CES, or MPS. Urine samples were collected immediately post-ingestion and at 60, 120, 180, and 240 min. BHI was calculated by dividing cumulative urine output after water consumption by cumulative urine output for each test beverage at each time point. The BHI for MPS was significantly higher at all time points compared to water (all p < 0.001) and CES (all p ≤ 0.01) but did not differ between CES and water at any time point. Drinking 1 L of MPS resulted in decreased cumulative urine output across the subsequent 4 h compared to water and CES, suggesting that a beverage containing milk permeate is superior to water and a traditional CES at sustaining positive fluid balance post-ingestion. Full article

(This article belongs to the Special Issue Hydration and Nutrition Considerations for Sports and Physical Activity)

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9 pages, 540 KiB

Open AccessArticle

Racial and Sex Differences in 24 Hour Urinary Hydration Markers among Male and Female Emerging Adults: A Pilot Study

by William M. Adams, Derek J. Hevel, Jaclyn P. Maher and Jared T. McGuirt

Nutrients 2020, 12(4), 1068; https://doi.org/10.3390/nu12041068 - 12 Apr 2020

Cited by 7 | Viewed by 3865

Abstract

The purpose of this study was to examine 24 h urinary hydration markers in non-Hispanic White (WH) and non-Hispanic Black (BL) males and females. Thirteen males (BL, n = 6; WH, n = 7) and nineteen females (BL, n = 16, WH, n [...] Read more.

The purpose of this study was to examine 24 h urinary hydration markers in non-Hispanic White (WH) and non-Hispanic Black (BL) males and females. Thirteen males (BL, n = 6; WH, n = 7) and nineteen females (BL, n = 16, WH, n = 3) (mean ± SD; age, 20 ± 4 y; height, 169.2 ± 12.2 cm; body mass, 71.3 ± 12.2 kg; body fat, 20.8 ± 9.7%) provided a 24 h urine sample across 7 (n = 13) or 3 (n = 19) consecutive days (148 d total) for assessment of urine volume (U_VOL), urine osmolality (U_OSM), urine specific gravity (U_SG), and urine color (U_COL). U_VOL was significantly lower in BL (0.85 ± 0.43 L) compared to WH college students (2.03 ± 0.70 L) (p < 0.001). Measures of U_OSM, U_SG, and U_COL, were significantly greater in BL (716 ± 263 mOsm∙kg⁻¹, 1.020 ± 0.007, and 4.2 ± 1.4, respectively) compared to WH college students (473 ± 194 mOsm∙kg⁻¹, 1.013 ± 0.006, 3.0 ± 1.2, and respectively) (p < 0.05). Differences in 24 h urinary hydration measures were not significantly different between males and females (p > 0.05) or between the interaction of sex and race/ethnicity (p > 0.05). Non-Hispanic Black men and women were inadequately hydrated compared to their non-Hispanic White counterparts. Our findings suggest that development of targeted strategies to improve habitual fluid intake and potentially overall health are needed. Full article

(This article belongs to the Special Issue Hydration and Nutrition Considerations for Sports and Physical Activity)

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9 pages, 455 KiB

Open AccessArticle

Exercise-Associated Hyponatremia during the Olympus Marathon Ultra-Endurance Trail Run

by Giannis Arnaoutis, Costas A. Anastasiou, HyunGyu Suh, Maria Maraki, Yiannis Tsekouras, Emmanouel Dimitroulis, Marcos Echegaray, Dimitra Papamichalopoulou, Spyridon Methenitis, Labros S. Sidossis and Stavros A. Kavouras

Nutrients 2020, 12(4), 997; https://doi.org/10.3390/nu12040997 - 03 Apr 2020

Cited by 10 | Viewed by 4244

Abstract

Research on hyponatremia during mountain marathons is scarce. The present study aimed to investigate the prevalence of exercise-associated hyponatremia during a 44-km trail running race that reached an altitude of 2780 m (Olympus Marathon). Sixty-two runners (five women) who completed the race participated [...] Read more.

Research on hyponatremia during mountain marathons is scarce. The present study aimed to investigate the prevalence of exercise-associated hyponatremia during a 44-km trail running race that reached an altitude of 2780 m (Olympus Marathon). Sixty-two runners (five women) who completed the race participated in the study (age: 34.4 ± 8.6 years; height: 1.77 ± 0.06 m; and weight: 75.3 ± 10.0 kg). Anthropometric characteristics, blood, and urine samples were collected pre- and post-race. Food and fluid intake were recorded at each checkpoint. Due to race regulations, the runners could not carry any additional food and fluids besides the ones provided at specific checkpoints. Five runners (8%) exhibited asymptomatic hyponatremia (serum sodium <135 mmol∙L⁻¹). Serum sodium in the hyponatremic runners decreased from 138.4 ± 0.9 (pre) to 131.4 ± 5.0 mmol∙L⁻¹ (post), p < 0.05. Plasma osmolality increased only in the eunatremic runners (pre: 290 ± 3; post: 295 ± 6 mmol∙kg⁻¹; p < 0.05). Plasma volume decreased more in the hyponatremic compared to eunatremic runners (−4.4 ± 2.0 vs. −3.2 ± 1.4%, p < 0.05). Lastly, dietary sodium intake was lower in the hyponatremic runners compared to eunatremic (789 ± 813 vs. 906 ± 672 mg; p < 0.05). The incidence of hyponatremia among the athletes was relatively low, possibly due to race conditions. Full article

(This article belongs to the Special Issue Hydration and Nutrition Considerations for Sports and Physical Activity)

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14 pages, 539 KiB

Open AccessArticle

Analysis of Sports Supplements Consumption in Young Spanish Elite Dinghy Sailors

by Israel Caraballo, Raúl Domínguez, Eduardo J. Guerra-Hernandez and Antonio J. Sánchez-Oliver

Nutrients 2020, 12(4), 993; https://doi.org/10.3390/nu12040993 - 03 Apr 2020

Cited by 24 | Viewed by 4050

Abstract

The sports performance of dinghy sailors is determined by their state of nutrition and hydration. Sports supplementation plays a prominent role in elite sailors, being essential in periods of competition due to its characteristics. This study aims to analyze the consumption of sports [...] Read more.

The sports performance of dinghy sailors is determined by their state of nutrition and hydration. Sports supplementation plays a prominent role in elite sailors, being essential in periods of competition due to its characteristics. This study aims to analyze the consumption of sports supplements (SS) in the different categories and groups of sailors based on the level of evidence, differentiating according to sex, competitive level, and type of boat. A total of 42 sailors from national and international levels and belonging to the Laser, 420, Techno-293 and RS:X classes participated in this study. They completed a questionnaire with questions about the consumption of SS and the possible repercussions on health and/or sports performance. The results were analyzed based on the different categorizations and group organization recently established by the Australian Institute of Sport (AIS), as well as by sex, level of competition and class to which the participants belonged. The male sailors and those who competed internationally had a higher prevalence in the consumption of SS. Among the classes of vessels studied, class 420 had the lowest SS consumption. SS intake was higher during competition days, regardless of sex or level of competition. Based on the classification established by the AIS, statistically significant differences were observed in sex, level of competition, and the type of boat. Full article

(This article belongs to the Special Issue Hydration and Nutrition Considerations for Sports and Physical Activity)

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15 pages, 2006 KiB

Open AccessArticle

Effects of Casein Hydrolysate Ingestion on Thermoregulatory Responses in Healthy Adults during Exercise in Heated Conditions: A Randomized Crossover Trial

by Yasuyuki Sakata, Chikako Yoshida, Yuka Fujiki, Yutaka Matsunaga, Hirohiko Nakamura, Takashi Shimizu, Yasuhiro Takeda and Tatsuro Amano

Nutrients 2020, 12(3), 867; https://doi.org/10.3390/nu12030867 - 24 Mar 2020

Cited by 3 | Viewed by 3444

Abstract

Food ingestion has been shown to affect thermoregulation during exercise, while the impact of protein degradant consumption remains unclear. We investigated the effects of casein hydrolysate ingestion on thermoregulatory responses during exercise in the heat. In a randomized, placebo-controlled, double-blind, crossover trial, five [...] Read more.

Food ingestion has been shown to affect thermoregulation during exercise, while the impact of protein degradant consumption remains unclear. We investigated the effects of casein hydrolysate ingestion on thermoregulatory responses during exercise in the heat. In a randomized, placebo-controlled, double-blind, crossover trial, five men and five women consumed either 5 g of casein hydrolysate or placebo. Thirty minutes after ingestion, participants cycled at 60% VO₂max until voluntary exhaustion wearing a hot-water (43 °C) circulation suit. Exercise time to exhaustion, body core temperature, forearm sweat rate, and forearm cutaneous vascular conductance did not differ different between the conditions. However, chest sweat rate and mean skin temperature increased upon casein hydrolysate ingestion compared with placebo during exercise. Increased chest sweat rate upon casein hydrolysate ingestion was associated with elevated sudomotor sensitivity to increasing body core temperature, but not the temperature threshold for initiating sweating. A positive correlation was found between chest sweat rate and plasma total amino acid concentration during exercise. These results suggest that casein hydrolysate ingestion enhances sweating heterogeneously by increasing peripheral sensitivity of the chest’s sweating mechanism and elevating skin temperature during exercise in the heat. However, the physiological link between plasma amino acid concentration and sweat rate remains unclear. Full article

(This article belongs to the Special Issue Hydration and Nutrition Considerations for Sports and Physical Activity)

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Review

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15 pages, 676 KiB

Open AccessReview

Up in the Air: Evidence of Dehydration Risk and Long-Haul Flight on Athletic Performance

by Damir Zubac, Alex Buoite Stella and Shawnda A. Morrison

Nutrients 2020, 12(9), 2574; https://doi.org/10.3390/nu12092574 - 25 Aug 2020

Cited by 6 | Viewed by 6561

Abstract

The microclimate of an airline cabin consists of dry, recirculated, and cool air, which is maintained at lower pressure than that found at sea level. Being exposed to this distinctive, encapsulated environment for prolonged durations, together with the short-term chair-rest immobilization that occurs [...] Read more.

The microclimate of an airline cabin consists of dry, recirculated, and cool air, which is maintained at lower pressure than that found at sea level. Being exposed to this distinctive, encapsulated environment for prolonged durations, together with the short-term chair-rest immobilization that occurs during long-haul flights, can trigger distinct and detrimental reactions to the human body. There is evidence that long-haul flights promote fluid shifts to the lower extremity and induce changes in blood viscosity which may accelerate dehydration, possibly compromising an athlete’s potential for success upon arrival at their destination. Surprisingly, and despite several recent systematic reviews investigating the effects of jet lag and transmeridian travel on human physiology, there has been no systematic effort to address to what extent hypohydration is a (health, performance) risk to travelers embarking on long journeys. This narrative review summarizes the rationale and evidence for why the combination of fluid balance and long-haul flight remains a critically overlooked issue for traveling persons, be it for health, leisure, business, or in a sporting context. Upon review, there are few studies which have been conducted on actual traveling athletes, and those that have provide no real evidence of how the incidence rate, magnitude, or duration of acute dehydration may affect the general health or performance of elite athletes. Full article

(This article belongs to the Special Issue Hydration and Nutrition Considerations for Sports and Physical Activity)

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23 pages, 2097 KiB

Open AccessReview

The Effect of Acute Hypohydration on Indicators of Glycemic Regulation, Appetite, Metabolism and Stress: A Systematic Review and Meta-Analysis

by Mitchell E. Zaplatosch and William M. Adams

Nutrients 2020, 12(9), 2526; https://doi.org/10.3390/nu12092526 - 20 Aug 2020

Cited by 3 | Viewed by 4551

Abstract

Evidence synthesizing the effects of acute body water losses on various markers of glycemic regulation, appetite, metabolism, and stress is lacking. Thus, the purpose of this review was to summarize the response of various hormonal changes involved in these physiologic functions to dehydration. [...] Read more.

Evidence synthesizing the effects of acute body water losses on various markers of glycemic regulation, appetite, metabolism, and stress is lacking. Thus, the purpose of this review was to summarize the response of various hormonal changes involved in these physiologic functions to dehydration. A comprehensive literature search for peer-reviewed research in the databases PubMed, Scopus, CINAHL, and SportDiscus was conducted. Studies were included if they contained samples of adults (>18 years) and experimentally induced dehydration as measured by acute body mass loss. Twenty-one articles were eligible for inclusion. Findings suggested cortisol is significantly elevated with hypohydration (standard mean difference [SMD] = 1.12, 95% CI [0.583, 1.67], p < 0.0001). Testosterone was significantly lower in studies where hypohydration was accompanied by caloric restriction (SMD= −1.04, 95% CI [−1.93, −0.14], p = 0.02), however, there were no changes in testosterone in studies examining hypohydration alone (SMD = −0.17, 95% CI [−0.51 0.16], p = 0.30). Insulin and ghrelin were unaffected by acute total body water losses. Acute hypohydration increases markers of catabolism but has a negligible effect on markers of glycemic regulation, appetite, anabolism and stress. Given the brevity of existing research, further research is needed to determine the impact of hydration on glucagon, leptin, peptide YY and the subsequent outcomes relevant to both health and performance. Full article

(This article belongs to the Special Issue Hydration and Nutrition Considerations for Sports and Physical Activity)

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22 pages, 1952 KiB

Open AccessReview

Effects of Intermittent Fasting on Specific Exercise Performance Outcomes: A Systematic Review Including Meta-Analysis

by Joana M. Correia, Inês Santos, Pedro Pezarat-Correia, Cláudia Minderico and Goncalo V. Mendonca

Nutrients 2020, 12(5), 1390; https://doi.org/10.3390/nu12051390 - 12 May 2020

Cited by 39 | Viewed by 24014

Abstract

Intermittent fasting (IF) has been studied in athletes during Ramadan and in those willing to decrease adiposity while maintaining or increasing lean body mass. The purpose of this systematic review was to summarize the effects of IF on performance outcomes. We searched peer-reviewed [...] Read more.

Intermittent fasting (IF) has been studied in athletes during Ramadan and in those willing to decrease adiposity while maintaining or increasing lean body mass. The purpose of this systematic review was to summarize the effects of IF on performance outcomes. We searched peer-reviewed articles in the following databases: PubMed, Web of Science and Sport Discus (up to December 2019). Studies were selected if they included samples of adults (≥18 years), had an experimental or observational design, investigated IF (Ramadan and time-restricted feeding (TRF)), and included performance outcomes. Meta-analytical procedures were conducted when feasible. Twenty-eight articles met the eligibility criteria. Findings indicated that maximum oxygen uptake is significantly enhanced with TRF protocols (SMD = 1.32, p = 0.001), but reduced with Ramadan intermittent fasting (Ramadan IF; SMD = −2.20, p < 0.001). Additional effects of IF may be observed in body composition (body mass and fat mass). Non-significant effects were observed for muscle strength and anaerobic capacity. While Ramadan IF may lead to impairments in aerobic capacity, TRF may be effective for improving it. As there are few studies per performance outcome, more research is needed to move the field forward. Full article

(This article belongs to the Special Issue Hydration and Nutrition Considerations for Sports and Physical Activity)

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