Nourishing Physical Productivity and Performance On a Warming Planet - Challenges and Nutritional Strategies to Mitigate Exertional Heat Stress.

PURPOSE OF REVIEW: Climate change is predicted to increase the frequency and severity of exposure to hot environments. This can impair health, physical performance, and productivity for active individuals in occupational and athletic settings. This review summarizes current knowledge and recent advancements in nutritional strategies to minimize the impact of exertional-heat stress (EHS).

Effect of Personalized Sodium Replacement on Fluid and Sodium Balance and Thermophysiological Strain During and After Ultraendurance Running in the Heat.

Purpose: To investigate the effect of personalized sweat sodium replacement on drinking behavior, sodium and water balance, and thermophysiological responses during and after ultraendurance running in hot conditions.

Methods: Nine participants (7 male, 2 female) completed two 5-hour treadmill runs (60% maximum oxygen uptake, 30°C ambient temperature), in a double-blind randomized crossover design, consuming sodium chloride (SODIUM) capsules to replace 100% of previously assessed losses or placebo (PLACEBO). Fluid was consumed ad libitum.

Effect of prebiotics, probiotics, and synbiotics on gastrointestinal outcomes in healthy adults and active adults at rest and in response to exercise-A systematic literature review.

Introduction: A systematic literature search was undertaken to assess the impact of pre-, pro-, and syn-biotic supplementation on measures of gastrointestinal status at rest and in response to acute exercise.

Methods: Six databases (Ovid MEDLINE, EMBASE, Cinahl, SportsDISCUS, Web of Science, and Scopus) were used. Included were human research studies in healthy sedentary adults, and healthy active adults, involving supplementation and control or placebo groups.

Transcriptomic Differences Between Monozygotic Adolescent Twins Discordant For Metabolic Syndrome Following Weight Loss: A Case Study.

This case reports peripheral blood mononuclear cell (PBMC) transcriptomic changes in a pair of male monozygotic pediatric twins with metabolic syndrome (MetS) undertaking assisted weight loss. These 14-year-old boys presented with similar baseline biochemistry and body composition. After a 16-week weight-loss intervention, percent body weight loss was similar (Twin A 12%, and Twin B 13%).

The impact of exercise modality on exercise-induced gastrointestinal syndrome and associated gastrointestinal symptoms.

Objectives: This study aimed to determine the impact of running and cycling exercise modalities on the magnitude of exercise-induced gastrointestinal syndrome (EIGS) and associated gastrointestinal symptoms (GIS).

Design: Parallel group trial design.

Methods: Twenty-eight endurance athletes (male n = 14, female n = 14) completed 2 h running at 55 % of maximal oxygen uptake or cycling at 55 % of maximal aerobic power in T 35 °C and 22 % RH.

Modelling sodium requirements of athletes across a variety of exercise scenarios - Identifying when to test and target, or season to taste.

Evidence suggests the focus for sodium replacement during exercise should be maintenance of plasma sodium concentration ([Na]) for any given total body water (TBW) volume. The sodium intake to achieve stable [Na] given known fluid and electrolyte intakes and losses can be mathematically estimated. Therefore the aim of this investigation was to model sodium requirements of athletes during exercise, observing the influence of sweat rate, exercise duration, body mass, baseline [Na] and sweat potassium [K], and relevance to competition (soccer, elite marathon, and 160 km ultramarathon running).

Feeding Tolerance, Glucose Availability, and Whole-Body Total Carbohydrate and Fat Oxidation in Male Endurance and Ultra-Endurance Runners in Response to Prolonged Exercise, Consuming a Habitual Mixed Macronutrient Diet and Carbohydrate Feeding During Exercise.

Using metadata from previously published research, this investigation sought to explore: (1) whole-body total carbohydrate and fat oxidation rates of endurance (e.g., half and full marathon) and ultra-endurance runners during an incremental exercise test to volitional exhaustion and steady-state exercise while consuming a mixed macronutrient diet and consuming carbohydrate during steady-state running and (2) feeding tolerance and glucose availability while consuming different carbohydrate regimes during steady-state running.

Exertional heat stress and sodium balance: Leaders, followers, and adaptations.

Exertional heat stress presents a different acute challenge to salt balance compared to at rest. Sodium (Na) and chloride (Cl) losses during exercise are overwhelmingly driven by eccrine sweat glands (the "leader"), with minimal urinary excretion. Total salt losses are therefore largely influenced by thermoregulatory need, although adaptations from prior heat exposure or altered dietary intake influences sweat gland ion reabsorption, and therefore sweat Na ([Na]) and Cl concentrations.

Exertional-heat stress-associated gastrointestinal perturbations during Olympic sports: Management strategies for athletes preparing and competing in the 2020 Tokyo Olympic Games.

Exercise-induced gastrointestinal syndrome (EIGS) is a common characteristic of exercise. The causes appear to be multifactorial in origin, but stem primarily from splanchnic hypoperfusion and increased sympathetic drive. These primary causes can lead to secondary outcomes that include increased intestinal epithelial injury and gastrointestinal hyperpermeability, systemic endotoxemia, and responsive cytokinemia, and impaired gastrointestinal function (i.

Sports Dietitians Australia Position Statement: Nutrition for Exercise in Hot Environments.

It is the position of Sports Dietitians Australia (SDA) that exercise in hot and/or humid environments, or with significant clothing and/or equipment that prevents body heat loss (i.e., exertional heat stress), provides significant challenges to an athlete's nutritional status, health, and performance.

Hydrogel Carbohydrate-Electrolyte Beverage Does Not Improve Glucose Availability, Substrate Oxidation, Gastrointestinal Symptoms or Exercise Performance, Compared With a Concentration and Nutrient-Matched Placebo.

The impact of a carbohydrate-electrolyte solution with sodium alginate and pectin for hydrogel formation (CES-HGel), was compared to a standard CES with otherwise matched ingredients (CES-Std), for blood glucose, substrate oxidation, gastrointestinal symptoms (GIS; nausea, belching, bloating, pain, regurgitation, flatulence, urge to defecate, and diarrhea), and exercise performance. Nine trained male endurance runners completed 3 hr of steady-state running (SS) at 60% V˙O2max, consuming 90 g/hr of carbohydrate from CES-HGel or CES-Std (53 g/hr maltodextrin, 37 g/hr fructose, 16% w/v solution) in a randomized crossover design, followed by an incremental time to exhaustion (TTE) test. Blood glucose and substrate oxidation were measured every 30 min during SS and oxidation throughout TTE.

Impact of 3-day high and low dietary sodium intake on sodium status in response to exertional-heat stress: a double-blind randomized control trial.

Purpose: To determine the impact of altering dietary sodium intake for 3 days preceding exercise on sweat sodium concentration [Na], and cardiovascular and thermoregulatory variables.

Methods: Fifteen male endurance athletes (runners n = 8, cyclists n = 7) consumed a low (LNa, 15 mg kg day) or high (HNa, 100 mg kg day) sodium diet, or their usual free-living diet [UDiet, 46 (37-56) mg kg day] for 3 days in a double-blind, randomized cross-over design, collecting excreted urine (UNa) and refraining from exercise. On day 4, they completed 2 h running at 55% [Formula: see text]O or cycling at 55% maximum aerobic power in T 35 °C.

Sodium Intake Beliefs, Information Sources, and Intended Practices of Endurance Athletes Before and During Exercise.

There is little information describing how endurance athletes perceive sodium intake in relation to training and competition. Using an online questionnaire, this study assessed the beliefs, information sources, and intended practices regarding sodium ingestion for training and competition. Endurance athletes (n = 344) from six English-speaking countries completed the questionnaire and were included for analysis.

Case Study: Nutrition Planning and Intake for Marathon des Sables-A Series of Five Runners.

This case study describes the nutrition plans, intakes and experiences of five ultra-marathon runners who completed the Marathon des Sables in 2011 and 2013; age 37 (28-43) y, height 184 (180-190) cm, body mass 77.5 (71-85.5) kg, marathon personal best 3:08 (2:40-3:32).