Utility of Body Weight, Urine Color, and Thirst Perception (WUT) in Determining Hydration in Young Adults.

Objective: The primary aim of this study was to assess the efficacy of the weight, urine, and thirst (WUT) framework in predicting dehydration after a body water manipulation protocol, while concurrently determining the individual and interactive contributions of the model components.

Methods: The total study sample was 93 participants (female, n = 47), recruited from two institutions. Phase 1 involved collecting daily hydration measures from free-living participants (study 1, 58 participants for 3 d; study 2, 35 participants for 7 d).

Exertional heat stress promotes the presence of bacterial DNA in plasma: A counterbalanced randomised controlled trial.

Objectives: The primary aim was to explore the impact of exertional-heat stress (EHS) promoted exercise-associated bacteraemia. A secondary aim was to examine if an amino acid beverage (AAB) intervention may mitigate exercise-associated bacteraemia.

Design: Counterbalanced randomised control trial.

Iterative assessment of a sports rehydration beverage containing a novel amino acid formula on water uptake kinetics.

Purpose: Rapid gastric emptying and intestinal absorption of beverages is essential for rapid rehydration, and certain amino acids (AA) may augment fluid delivery. Three sugar-free beverages, containing differing AA concentrations (AA + PZ), were assessed for fluid absorption kinetics against commercial sugar-free (PZ, GZ) and carbohydrate-containing (GTQ) beverages.

Methods: Healthy individuals (n = 15-17 per study) completed three randomised trials.

Effectiveness of an amino acid beverage formulation in diarrhea-predominant irritable bowel syndrome: A pragmatic real-world study.

Background: Amino-acid based medical foods have shown promise in alleviating symptoms of drug induced gastrointestinal side effects; particularly, diarrhea-predominant symptoms. Irritable bowel syndrome (IBS) is a gastrointestinal disorder that affects up to 9% of people globally, with diarrhea predominant IBS (IBS-D) being the most prevalent subtype. Further trials are needed to explore potential added benefits when integrated into standard care for IBS-D.

Forecasting individual exercise sweat losses from forecast air temperature and energy expenditure.

Introduction: Recent success in predicting individual sweat losses from air temperature and energy expenditure measurements suggests a potential for forecasting individual sweat losses for future combinations of environment and exercise. The purpose of this study is to determine the plausibility of accurately forecasting exercise sweat losses from meteorological air temperature forecasts and individual running energy expenditure forecasts. The potential impact on plasma sodium is also estimated when setting drinking rates equal to forecast sweat losses.

Individualized monitoring of heat illness risk: novel adaptive physiological strain index to assess exercise-heat strain from athletes to fully encapsulated workers.

. Exercise-heat strain estimation approaches often involve combinations of body core temperature (Tcore), skin temperature (Tsk) and heart rate (HR). A successful existing measure is the 'Physiological Strain Index' (PSI), which combines HR and Tcore values to estimate strain.

Change of Seasons: Boston Marathon Wet Bulb Globe Temperature Index in October.

Introduction: The importance of providing wet bulb globe temperature (WBGT) heat stress flag category measurements in real time is well recognized by road race directors, and it is bound to become even more important with the rise of extreme weather and pandemic outbreaks. The purpose of this paper is to describe the WBGT index and its components measured during the 125th running of the Boston Marathon on October 11, 2021, for qualitative comparison to measurements made similarly on its traditional April date, 2014 to 2019.

Methods: Monitoring occurred at the 7 km, 18 km, and 32 km marks of the race in the towns of Ashland, Natick-Wellesley, and Newton.

Amino Acid-Based Beverage Interventions Ameliorate Exercise-Induced Gastrointestinal Syndrome in Response to Exertional-Heat Stress: The Heat Exertion Amino Acid Technology (HEAAT) Study.

The study aimed to determine the effects of two differing amino acid beverage interventions on biomarkers of intestinal epithelial integrity and systemic inflammation in response to an exertional-heat stress challenge. One week after the initial assessment, participants (n = 20) were randomly allocated to complete two exertional-heat stress trials, with at least 1 week washout. Trials included a water control trial (CON), and one of two possible amino acid beverage intervention trials (VS001 or VS006).

Post-exercise rehydration: Comparing the efficacy of three commercial oral rehydration solutions.

Introduction: This study compared the efficacy of three commercial oral rehydration solutions (ORS) for restoring fluid and electrolyte balance, after exercise-induced dehydration.

Method: Healthy, active participants ( = 20; ♀ = 3; age ∼27 y, Opeak ∼52 ml/kg/min) completed three randomised, counterbalanced trials whereby intermittent exercise in the heat (∼36°C, ∼50% humidity) induced ∼2.5% dehydration.

Effects of body size and countermeasure exercise on estimates of life support resources during all-female crewed exploration missions.

Employing a methodology reported in a recent theoretical study on male astronauts, this study estimated the effects of body size and aerobic countermeasure (CM) exercise in a four-person, all-female crew composed of individuals drawn from a stature range (1.50- to 1.90-m) representative of current space agency requirements (which exist for stature, but not for body mass) upon total energy expenditure (TEE), oxygen (O) consumption, carbon dioxide (CO) and metabolic heat (H) production, and water requirements for hydration, during space exploration missions.

Personalized Hydration Requirements of Runners.

This study sought to (a) estimate how the duration of running influences sweat losses and contributes to the daily fluid requirement, and (b) empirically estimate the drinking rates required to prevent significant dehydration (≥2% body weight as body water). Individual sweating data and running duration were obtained from male (n = 83) and female (n = 36) runners (n = 146 total observations) performing under highly heterogeneous conditions and over a range of exercise durations (33-280 min). Running <60 min/day increased daily fluid needs by a factor of 1.

Physiology and Performance Prospects of a Women's Sub-4-Minute Mile.

When will women run a sub-4-minute mile? The answer seems to be a distant future given how women's progress has plateaued in the mile, or its better studied metric placeholder, the 1500 m. When commonly accepted energetics principles of running, along with useful field validation equations of the same, are applied to probe the physiology underpinning the 10 all-time best women's mile performances, insights gained may help explain the present 12.34-second shortfall.

Predicted sweat rates for group water planning in sport: accuracy and application.

This study tested the accuracy of a novel, limited-availability web application (HQ™) for predicting sweat rates in a variety of sports using estimates of energy expenditure and air temperature only. The application of predictions for group water planning was investigated for soccer match play. Fourteen open literature studies were identified where group sweat rates were reported (n = 20 group means comprising 230 individual observations from 179 athletes) with fidelity.

Can an amino acid mixture alleviate gastrointestinal symptoms in neuroendocrine tumor patients?

Background: Neuroendocrine tumors, although relatively rare in incidence, are now the second most prevalent gastrointestinal neoplasm owing to indolent disease biology. A small but significant sub-group of neuroendocrine tumor patients suffer from diarrhea. This is usually secondary to carcinoid syndrome but can also be a result of short gut syndrome, bile acid excess or iatrogenic etiologies.

Earlier Boston Marathon Start Time Mitigates Environmental Heat Stress.

Purpose: This study aimed to compare the wet bulb globe temperature (WBGT) index and other environmental parameters between early and late Boston Marathon race start times from 1995 to 2016.

Methods: Environmental data from 1995 to 2016 (excluding 1996) were used to compare two identical time frames using the 0900-1300 h start versus the 1100-1500 h start. This included the WBGT, dry bulb (Tdb), black globe (Tbg), wet bulb (Twb), solar radiation, relative humidity, and air water vapor pressure.

Are oral rehydration solutions optimized for treating diarrhea?

Background: A historical turning point occurred in the treatment of diarrhea when it was discovered that glucose could enhance intestinal sodium and water absorption. Adding glucose to salt water (oral rehydration solution, ORS) more efficiently replaced intestinal water and salt losses.

Aim: Provide a novel hypothesis to explain why mainstream use of ORS has been strongly recommended, but weakly adopted.

Personalized fluid and fuel intake for performance optimization in the heat.

It is well appreciated that a loss of body water (dehydration) can impair endurance performance and that the effect is magnified by environmental heat stress. A majority of professional sports medicine and nutrition organizations recommend drinking during exercise to replace sweat losses and prevent dehydration, while also avoiding frank over-hydration. Knowledge of sweating rate, which is highest in the heat for any given metabolic rate, is therefore considered key to developing a sound drinking strategy.

Randomized Study of enterade® to Reduce Diarrhea in Patients Receiving High-Dose Chemotherapy and Autologous Hematopoietic Stem Cell Transplantation.

High-dose chemotherapy frequently causes injury to the gastrointestinal mucosa, resulting in diarrhea. The purpose of the current study was to assess the tolerability and efficacy of enterade® in reducing ≥ grade 2 diarrhea (G2D) in association with high-dose melphalan followed by autologous stem cell transplantation (ASCT). We conducted a prospective, double blinded, multi-center trial in which 114 subjects were randomized to receive enterade® or placebo twice daily during the transplant hospitalization.

Heat Acclimation Improves Heat Tolerance Test Specificity in a Criteria-dependent Manner.

Purpose: This study aimed to characterize HTT specificity and to determine any effect of HA on the outcome.

Methods: Thirteen unacclimatized, healthy men (V˙O2peak, 43.0 ± 4.

Body size and its implications upon resource utilization during human space exploration missions.

The purpose of this theoretical study was to estimate the effects of body size and countermeasure (CM) exercise in an all-male crew composed of individuals drawn from a height range representative of current space agency requirements upon total energy expenditure (TEE), oxygen (O) consumption, carbon dioxide (CO) and metabolic heat (H) production, and water requirements for hydration, during space exploration missions. Using a height range of 1.50- to 1.

Independent Influence of Skin Temperature on Whole-Body Sweat Rate.

Purpose: It is often assumed that a person with a higher mean skin temperature (Tsk) will sweat more during exercise. However, it has not yet been demonstrated whether Tsk describes any individual variability in whole-body sweat rate (WBSR) independently of the evaporative requirement for heat balance (Ereq).

Methods: One hundred forty bouts of 2-h treadmill walking completed by a pool of 21 participants (23 ± 4 yr, 174 ± 8 cm, 76 ± 11 kg, 1.

Endurance test selection optimized via sample size predictions.

Selecting the most appropriate performance test is critical in detecting the effect of an intervention. In this investigation we ) used time-trial (TT) performance data to estimate sample size requirements for test selection and ) demonstrated the differences in statistical power between a repeated-measures ANOVA (RM-ANOVA) and analysis of covariance (ANCOVA) for detecting an effect in parallel group design. A retrospective analysis of six altitude studies was completed, totaling 105 volunteers.

The accurate prediction of sweat rate from energy expenditure and air temperature: a proof-of-concept study.

This proof-of-concept study used a web application to predict runner sweat losses using only energy expenditure and air temperature. A field study (FS) of = 37 runners was completed with = 40 sweat loss observations measured over 1 h (sweat rate, SR). Predictions were also compared with 10 open literature (OL) studies in which individual runner SR was reported ( = 82; 109 observations).

Potential for dehydration to impact the athlete biological passport.

In order to inform the Athlete Biological Passport (ABP), this study determined whether the elevation in hemoglobin (Hb) following intracellular or extracellular dehydration would trigger an atypical passport finding (ATPF). Seven male and three female volunteers (age: 23 ± 4 y; height: 170 ± 8 cm; body mass: 78 ± 12 kg) were carefully euhydrated (EUH) to determine baseline Hb levels. Volunteers then completed both an exercise-induced sweating dehydration (SW) protocol and a diuretic-induced dehydration (DI) protocol.

Biological variation of arginine vasopressin.

Purpose: There is growing interest in the measurement of plasma levels of arginine vasopressin (AVP) for the assessment of mild dehydration. However, the principles of biological variation have not been applied to the study of AVP and understanding biological variation of AVP may provide insights regarding measurement thresholds. The purpose of this investigation was to determine the biological variation of AVP in healthy euhydrated individuals to understand the potential for establishing both static and/or change thresholds of importance.