BACKGROUND: Voluntary dehydration is a condition where humans do not drink appropriately in the presence of an adequate fluid supply. This may adversely affect their physical and intellectual performance. The present study aimed to describe the prevalence of voluntary dehydration among elementary school children of different ethnicities and countries of birth. METHODS: Four hundred and [...]
Cognitive and mood decrements resulting from mild dehydration and glucose consumption were studied. Men and women (total N = 54; M age = 19.8 yr., SD = 1.2) were recruited from college athletic teams. Euhydration or dehydration was achieved by athletes completing team practices with or without water replacement. Dehydration was associated with higher thirst [...]
An in-hospital prospective, observational cohort study was conducted to assess the effects of type of feeding (exclusively breastfed [EBF] vs partially breastfed [PBF]) on the hydration status of near-term newborns in the first week of life. A total of 205 babies of 35 to 37 weeks of completed gestation were enrolled (82 in the EBF [...]
Studies have shown that beverages containing glycerol can enhance and maintain hydration status and may improve endurance exercise performance by attenuating adverse physiological changes associated with dehydration. Improvements to performance include increased endurance time to exhaustion by up to 24%, or a 5% increase in power or work. However, some studies have found no performance [...]
Assessing hydration, that is, total body water (TBW) in adolescent athletes should be part of a comprehensive training program. However, there are no specific methods to assess TBW in young athletes. Moreover, the use of traditional techniques developed in healthy youths, based on a 2-compartment model, may yield inaccurate TBW estimates in young athletes. Therefore, [...]
PURPOSE OF REVIEW: Physical exercise can be both beneficial and harmful for the gastrointestinal tract in a dose-effect relationship between its intensity and health. Mild-to-moderate intensity exercises play a protective role against colon cancer, diverticular disease, cholelithiasis and constipation, whereas acute strenuous exercise may provoke heartburn, nausea, vomiting, abdominal pain, diarrhea and even gastrointestinal bleeding. [...]
It has been reported that endurance exercise-trained men have decreases in cardiac output with no change in systemic vascular conductance during post-exercise hypotension, which differs from sedentary and normally active populations. As inadequate hydration may explain these differences, we tested the hypothesis that fluid replacement prevents this post-exercise fall in cardiac output, and further, exercise [...]
The impact of prior heat stress on subsequent aerobic exercise-heat performance has not been studied. PURPOSE: To determine whether prior heat stress degrades subsequent aerobic exercise performance in the heat. METHODS: Eighteen nonheat acclimated males were trained (four practice trials) on an aerobic exercise performance test in 22 degrees C and then divided into two [...]
This investigation examined the distinct and interactive effects of initial hydration state, exercise-induced dehydration, and water rehydration in a hot environment. On four occasions, 10 men performed a 90-min heat stress test (treadmill walking at 5.6 km/h, 5% grade, 33 degrees C, 56% relative humidity). These heat stress tests differed in pretest hydration [2 euhydrated [...]
The purpose of this study was to examine the effects of fluid replacement on power output (PO), rating of perceived exertion (RPE), heart rate (HR), body weight (BW), urine osmolarity (Uosm), and urine electrolyte concentrations ([UNa+], [UK+], [UCl-]) in physically active men (n = 4) and women (n = 7). The participants were asked to [...]