Context: The training stress of heat acclimatization optimizing exercise performance in a hot environment can be demanding.
Objectives: This study evaluated the efficiency of different single heating protocols to elevate core temperature.
Design: Not randomized controlled trial.
Sweat evaporation is critical to human thermoregulation, but current understanding of the process on 20 μm to 2 cm scale is limited. To this end, we introduce a wind-tunnel-shaped ventilated capsule with an infrared window for simultaneous infrared sweat imaging and evaporation rate measurement. Implementing the capsule in pilot human subject tests suggests that the common assumption of sweat being an isothermal film is only valid when the evaporation rate is low and sweat forms puddles on the skin.
View Article and Find Full Text PDFFew previous review articles have focused on the associations between inadequate daily water intake (LOW) or urinary biomarkers of dehydration (D; low urine volume or high urine osmolality) and multiple diseases. Accordingly, we conducted manual online searches (47 key words) of the PubMed, Embase, and Google Scholar databases with these inclusion criteria: English language, full-text, peer reviewed, no restriction on research design, and three publications minimum. Initially, 3,903 articles were identified based on their titles and abstracts.
View Article and Find Full Text PDFPurpose: Relationships between body weight, urine color (Uc), and thirst level (WUT) have been proposed as a simple and inexpensive self-assessment method to predict dehydration. This study aimed to determine if this method also allowed us to accurately identify a low vs. high urine concentration in (tactical) athletes.
View Article and Find Full Text PDFBackground: Although prior evidence indicates that water intake is important for health, the ability to accurately measure community-dwelling intake is limited. Only a few studies have evaluated self-reported water intake against an objective recovery biomarker.
Objectives: The aim was to compare preformed water intakes (all sources including food) by multiple Automated Self-Administered 24-h recalls (ASA24s), food frequency questionnaires (FFQs), and 4-d food records (4DFRs) against a recovery biomarker, doubly labeled water (DLW), to assess measurement error.
The purpose of this investigation was to characterize factors that predict tap water mistrust among Phoenix, Arizona Latinx adults. Participants (n = 492, 28 ± 7 years, 37.4% female) completed water security experience-based scales and an Adapted Survey of Water Issues in Arizona.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
June 2023
The purpose of this study was to examine whether hot yoga could attenuate sodium-induced pressor responses and endothelial dysfunction in Black females. Fourteen participants (ages 20-60 yr old) completed 3 days of low-sodium intake (≤31 mmol/day) followed by 3 days of high-sodium intake (201 mmol/day). Ambulatory blood pressure (BP), 24-h urinary sodium excretion, flow-mediated dilation (FMD), urine-specific gravity, and hematocrit were measured during/after each dietary phase.
View Article and Find Full Text PDFBackground/aim: Bone response to exercise depends on the type and size of the mechanical stimulus. In rowing, athletes are exposed to low mechanical but large compression loads mainly on the trunk. Thus, this study aimed to investigate the impact of rowing on total and regional bone quality and bone turnover parameters in elite rowing athletes vs.
View Article and Find Full Text PDFEducation may improve hiker safety on trails. To investigate the impact of an educational video on hiker fluid selection and fluid consumption in a hot environment. Quasi-experimental field study at hiking trails in which the intervention group (INT) viewed a three-minute hydration education video, whereas the control group (CON) did not.
View Article and Find Full Text PDFThe ideal lifestyle intervention to battle both obesity and diabetes is currently unknown. The aim of this pilot uncontrolled intervention trial was to assess the effect of a modified Mediterranean diet (MedDiet) on weight loss and glucoregulation among overweight/obese adults. Eleven men and women with overweight/obesity, aged 37 ± 12 years, participated in a free-living intervention until 10% weight loss was achieved.
View Article and Find Full Text PDFFemales are prone to urinary tract infections (UTIs) due to estrogen fluctuations affecting vaginal flora. While menstruating, increased fluid consumption to support urination frequency and void volume may be important, as the urethra and urinary tract are more predisposed to bacteria, particularly UTI pathogens. This study aimed to investigate the impact of hydration on urinary tract health during menstruation among underhydrated premenopausal women.
View Article and Find Full Text PDFPurpose: Recent studies suggest that 24-h urine osmolality (UOsm) for optimal water intake should be maintained < 500 mmol·kg. The purpose of this study was to determine the total water intake (TWI) requirement for healthy adults to maintain optimal hydration as indicated by 24-h urine osmolality < 500 mmol·kg.
Methods: Twenty-four-hour UOsm was assessed in 49 men and 50 women residing in the United States (age: 41 ± 14 y, body mass index: 26.
Objective: Physiological systems responsible for water homeostasis and energy metabolism are interconnected. This study hypothesized altered responses to dehydration including thirst, ad libitum water intake, and copeptin in men with obesity.
Methods: Forty-two men (22 lean and 20 with obesity) were stimulated by a 2-hour hypertonic saline infusion and a 24-hour water deprivation.
The purpose of our study was to determine the responses to an acute water bolus in long-term oral contraception (OCP) users. Seventeen female volunteers (27 ± 5 y, 64.1 ± 13.
View Article and Find Full Text PDFExercise-associated hyponatremia (EAH) is defined as a serum sodium concentration under 135 mmol·L during or within 24 h of exercise. Increasing interest in endurance events has led to a higher number of athletes presenting with this potentially life-threatening condition. EAH is largely caused by the overconsumption of hypotonic fluids leading to weight gain during exercise.
View Article and Find Full Text PDFElevated body mass index (BMI) has been associated with elevated urine osmolality (UOsm), despite having higher total water intake, but it is unclear if overweight/obese individuals have reduced thirst. In this observational study, we found that overweight/obese individuals had higher UOsm compared to normal-weight individuals (749 ± 37 vs. 624 ± 35 mmol•kg; P < 0.
View Article and Find Full Text PDFJ Sports Med Phys Fitness
October 2022
Background: The aim of this study was to determine the physiological, perceptual, and exercise performance responses to breathing cooled air during and following exercise in the heat.
Methods: Twelve trained male cyclists (26±4 y; 180.5±5.
The purpose of this study was to investigate the relationship between volume regulatory biomarkers and the estrogen to progesterone ratio (E:P) prior to and following varying methods and degrees of dehydration. Ten women (20 ± 1 year, 56.98 ± 7.
View Article and Find Full Text PDFInsufficient water intake is associated with adverse health outcomes, including chronic disease prevalence and mortality. Adherence to Institute of Medicine total water intake (TWI) recommendations has been low in recent decades, and TWI has been consistently lower in Latinx adults compared with non-Hispanic (NH) white adults. While overall plain water intake is similar between Latinx and NH white adults, Latinx adults consistently consume significantly more bottled water and less tap water.
View Article and Find Full Text PDFHydration is a particular concern for infants and young children due to their greater risk of dehydration. However, studies on their water intakes are scarce. The current survey aimed to analyse total water intake (TWI) in non-breastfed children aged 0·5-35 months compared with the adequate intake (AI) for the same age group set by the European Food Safety Authority and to examine the different contributors to TWI as well as beverage consumption patterns.
View Article and Find Full Text PDFAlthough it is well established that dehydration has a negative impact on thermoregulation during exercise in the heat, it is unclear whether this effect of dehydration is different between men and women, or across the phases of the menstrual cycle (MC). Twelve men and seven women (men: 20 ± 2 years, 70.13 ± 10.
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