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The effect of the consumption of water on the memory and attention of children

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Abstract

The impact of asking children to drink water during their school days, and its possible influence on school performance, has been little considered using intervention studies. Therefore in the afternoon the cognitive functioning of 40 children (mean of 8 years and 7 months) was assessed twice, once after drinking 300 ml of water and on another day when no water was provided. Memory was assessed by the recall of 15 previously presented objects. Recall was significantly better on the occasions when water had been consumed. The ability to sustain attention was measured by asking the child to respond to a light that followed an auditory warning after a delay of either 3 or 12 s. The ability to sustain attention was not significantly influenced by whether water had been drunk.

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... Benton and Burgess, 2009 [46] Examined the influence of giving additional water to school children on measures of memory and attention. ...
... Our search identified nine studies, which are summarized in Table 2. Similar to data for adults, results from studies on hydration and cognition and mood in children are mixed. Studies in children have reported improvements in visual attention [38,41,44,45,54], but not sustained attention [46] following acute water consumption. The effect of acute effects of hydration on memory is dependent on the type of memory assessed, whereby some studies reported improvements in immediate memory [46] and others reporting no effects on verbal memory [38], visual memory [44], and story memory [45]. ...
... Studies in children have reported improvements in visual attention [38,41,44,45,54], but not sustained attention [46] following acute water consumption. The effect of acute effects of hydration on memory is dependent on the type of memory assessed, whereby some studies reported improvements in immediate memory [46] and others reporting no effects on verbal memory [38], visual memory [44], and story memory [45]. For the aforementioned acute studies, although a majority of studies did not assess baseline hydration status, it is likely that the children were mildly hypohydrated prior to acute water intake. ...
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Although adequate hydration is essential for health, little attention has been paid to the effects of hydration among the generally healthy population. This narrative review presents the state of the science on the role of hydration in health in the general population, specifically in skin health, neurological function (i.e., cognition, mood, and headache), gastrointestinal and renal functions, and body weight and composition. There is a growing body of evidence that supports the importance of adequate hydration in maintaining proper health, especially with regard to cognition, kidney stone risk, and weight management. However, the evidence is largely associative and lacks consistency, and the number of randomized trials is limited. Additionally, there are major gaps in knowledge related to health outcomes due to small variations in hydration status, the influence of sex and sex hormones, and age, especially in older adults and children.
... Concerning the water intake period, half of the studies included in this review ingested it between 30 min to 2 h 7,9,24,27 , while others throughout the school day 6,25,28 . Khan et al. (2019) 26 performed two interventions of 4 days each, while low water intake (0.5 L/day) was performed in one group, and there was a high water intake (2.5 L) in the other group. ...
... Additionally, attention and cognitive control were described in three studies that used the Flanker task 26,28 . Another study used the paradigm of Shakow to assess the ability to maintain attention 24 28 to assess spatial attention and switching skills between two different tasks (Table 3). Some studies used tests for memory, visual attention, and visuomotor skills, such as a difference in direct and indirect images, line tracing task 7,10,25 , forward, and reverse digit recall 6,9,10,25,27,29 . ...
... Some studies used tests for memory, visual attention, and visuomotor skills, such as a difference in direct and indirect images, line tracing task 7,10,25 , forward, and reverse digit recall 6,9,10,25,27,29 . One study used the Recall of objects test 24 , while another study used the Corsi Black-Tapping Task to examine the performance of visuospatial attention and working memory 28 . In the study by Fadda et al. (2012) 6 , the researchers chose to adapt an Italian test battery, Wechsler Intelligence Scale for Children -III, and the Group Embedded Figure Test. ...
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Objective: Hydration can favor cognitive functions during childhood and adolescence, helping with daily and school activities. This study aimed to identify possible interactions between hydration and memory in children and adolescents. Methods: This is a systematic review with meta-analysis. The bibliographic search was conducted in the MEDLINE/PubMed, SciELO, LILACS, Web of Science, Embase, and Cochrane Library databases, through a combination of the descriptors: “hydration” AND “memory”; “hydration” AND “memory” AND “child”; “hydration” AND “memory” AND “children”; “organism hydration status” AND “memory”; “organism hydration status” AND “memory” AND “child”. Results: The search resulted in 816 articles, of which ten were selected for qualitative synthesis and two for the meta-analysis. The results indicated that hydration could not enhance working, visual and visuomotor memories, or visual attention (Line Tracing Task, MD 0.67, 95% CI -0.87 to 2.22; Indirect Image Difference, MD 0.32, 95% CI -0.75 to 1.40; Letter Cancellation, MD 1.68, 95% CI -0.81 to 4.17). Conclusion: From the obtained results, hydration per se does not reinforce working, visual and visuomotor memories, or visual attention. However, there are still gaps regarding other types of memory and cognitive, motor, nutritional and environmental integration.
... Many studies investigating cognitive enhancement after drinking water have focused on memory. Studies in children report that visual memory (Edmonds & Burford, 2009) and object recall (Benton & Burgess, 2009) improve approximately 20 to 30 min after drinking water ranging from 250 to 300 ml, but that memory for stories does not (Edmonds & Burford, 2009). Adults' word recall in participants who fasted overnight was unaffected by drinking either 150 ml water, or after a second 150 ml water drink (Neave et al., 2001), nor did it improve after drinking 300 ml water (150 ml on two occasions) during a dehydration protocol . ...
... In contrast to the effects of drinking on working memory, performance on two long-term recall tasks was not improved after drinking water. There are limited published data on the effects of drinking on long-term memory, with one study in children showing an acute effect of drinking on picture recall (Benton & Burgess, 2009), but two showing no effect on adults' word recall Neave et al., 2001). Firm conclusions about the question of whether acute drinking water interventions enhances long-term memory cannot be made on the basis of just three studies (and only two in adults), but here we consider why there may be conflicting findings. ...
... For example, 300 ml water may not be sufficient, or that the interval between drinking and test was too short, or too long. While children's long-term picture recall improved between 20 and 35 min after drinking 300 ml water (Benton & Burgess, 2009), it is possible that 300 ml may be insufficient to enhance performance in adults, given their larger body size and associated increased water demands (European Food Safety Authority (EFSA), 2010). Finding that there was no effect on adults' word recall after drinking 150 ml water following an overnight fast (Neave et al., 2001) might suggest that this amount is not sufficient for thirsty adults. ...
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Previous studies suggest that acute water drinking interventions enhance working memory, particularly digit span. The aims of the present study were twofold. Firstly, to investigate whether the working memory enhancements extend to different components of working memory. Secondly, to evaluate whether drinking water would improve long-term memory task performance. Seventy-four adult participants completed baseline tests and then either drank 300 ml water or nothing. They completed a thirst scale, two working memory tests (digit span and Corsi blocks) and two long-term memory tests (picture recall and word recall). After this, the water group was offered 300 ml water and the control group did not have a drink. Following a 20 min interval, the measures were repeated. The results showed that both working memory tests were improved by drinking water, but long-term memory assessments were not affected. This study adds to the body of evidence that suggests that acute drinking interventions in adults enhance working memory, but not long-term memory, and that it may not be restricted to particular components of working memory.
... The main findings of this review were that acute fluid intake (not necessarily hydration status) was the only intervention that frequently resulted in favorable changes to cognitive task performance (Table 1), but fluid intake intervention over more extended durations (Table 2) or when participants were separated by hydration status classification (Table 3) failed to consistently elicit positive outcomes related to improved hydration status. In 2011, Benton provided a narrative recap of three published articles (Benton & Burgess, 2009;Edmonds & Burford, 2009;Edmonds & Jeffes, 2009) positing a strong case that acute fluid intake more consistently results in cognitive enhancement in children than adult populations. None of the studies cited provide any corroborating mechanistic evidence to support Benton's position, but three additional studies Edmonds et al., 2017;Perry et al., 2015) with data supporting the hypothesis have been published since 2011. ...
... Results were separated into groups based on median splits of participants exhibiting the lowest (LOW) drops (i.e., sustained higher urine osmolality) or highest drops (HIGH) (i.e., large decrease from morning to mid-day urine osmolality) of urine osmolality during water intervention trials compared within to their own restricted fluid intake trial. Only long-term results presented in this table combination of these functions (Benton & Burgess, 2009;Edmonds & Burford, 2009;Edmonds & Jeffes, 2009;Edmonds et al., 2017;Perry et al., 2015) by a single fluid intake bout (Table 1). Acute water consumption failed to elicit an effect on psychomotor function in Edmonds and Burford, (2009) or Edmonds and Jeffes, (2009). ...
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Children (< 18 years of age) face unique physiological and sociological obstacles in regards to hydration. Research regarding the impact of hydration on children’s cognitive performance lags considerably when compared to adults. Following methods of a systematic literature search, an exploratory review of current literature examining hydration and cognitive function in children is presented. Fourteen published studies in which fluid intake was manipulated or participants were grouped based on hydration status markers met a priori inclusion criteria. No studies altered hydration status via sweat loss. Many studies were conducted in participants’ school settings. Results were often reported as association between hydration status and performance with multiple covariates (e.g., IQ or socioeconomic status) versus contrast of raw scores between conditions, limiting direct, magnitude-based comparisons. Three major methodological themes were used to classify articles: (a) studies with a single, acute fluid intake intervention, (b) hydration interventions in which investigators attempted to intentionally alter fluid intake for an extended period, and (c) studies comparing cognitive results based on hydration status markers or reported fluid intake. The only intervention that consistently resulted in an improvement in cognitive task performance was acute fluid consumption. These results suggest encouragement to consume ~ 250 ml of water 20–60 min before challenging academic engagement may be advantageous to children. Research on mechanistic origins that explain acute fluid intake benefits on cognitive performance, differences in cognitive performance improvements due to fluid intake among children versus adults, and if routine academic tasks are improved by acute fluid intake is warranted.
... Other studies have also reported that people with NI are at a higher risk for dehydration [130,131]. Deficiency of body water due to OD and low intake causes dehydration, which might also contribute to impaired cognitive function [132,133]. Dehydration in children and young people is associated with reduced cognitive response, while correct hydration has a positive effect on cognitive function [133]. In our study, the prevalence of dehydration was very high (70%) and mainly hypertonic. ...
... Deficiency of body water due to OD and low intake causes dehydration, which might also contribute to impaired cognitive function [132,133]. Dehydration in children and young people is associated with reduced cognitive response, while correct hydration has a positive effect on cognitive function [133]. In our study, the prevalence of dehydration was very high (70%) and mainly hypertonic. ...
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Background: Special needs schools (SNS) educate children and young people with major neurological disabilities who are at high risk of oropharyngeal dysphagia (OD) and malnutrition (MN). We aimed to assess the prevalence of OD, MN, dehydration (DH), and oral health (OH) in students at an SNS. Methods: A cross-sectional observational study was conducted at SNS L'Arboç, Catalonia, Spain. We assessed (a) demographics, health status, comorbidities, and gross motor function classification system (GMFCS), (b) swallowing function, oral-motor evaluation, masticatory capacity, and EDACS classification for eating and drinking abilities, (c) nutritional and DH status (anthropometry, bioimpedance and dietary records), and (d) OH (Oral Hygiene Index Simplified). Results: A total of 33 students (mean age 13.3 years; 39.4% level V of GMFCS) were included. Main diagnosis was cerebral palsy at 57.6%. All students presented OD, 90.6% had impaired safety, 68.7% were at levels II-III of EDACS, and 31.3% required PEG; furthermore, 89.3% had chronic MN, 21.4% had acute MN, 70% presented intracellular DH, and 83.9% presented impaired OH. Conclusion: MN, DH, OD, and poor OH are highly prevalent conditions in students with cerebral palsy and other neurological disabilities and must be specifically managed through nutritional and educational strategies. The multidisciplinary team at SNS should include healthcare professionals specifically trained in these conditions.
... Earlier work in this area suggested that elevated urinary markers of hydration-such as urine osmolality-are associated with poorer short-term memory performance in children (11,12). Although limited, a handful of interventions also indicate that providing children with water, without prior induction of dehydration, may result in acute benefits for memory and visual attention (12)(13)(14)(15)(16). For example, Perry et al. (17) used a 2-condition crossover design to examine changes in working memory and attention among 9-to 12-y-olds following provision of either 750 mL of water throughout the morning hours compared with no water (17). ...
... Furthermore, the results of this work extend the potential implications of changes in hydration to cognitive function among preadolescents. While limited, a handful of previous intervention studies has assessed cognitive function following the provision of water, without prior induction of dehydration (12)(13)(14). Benton and Burgess (13) observed improvements in short-term memory following the provision of 200 mL of water among 8-to 9-y-olds. Edmonds and Jeffes (14) observed that children who were allowed access to water, up to 500 mL, outperformed their fluid-deprived counterparts on visual attention tasks but not visual memory or visuomotor tasks. ...
Article
Background: Hydration effects on cognition remain understudied in children. This is concerning since a large proportion of US children exhibit insufficient hydration. Objective: This study investigated the effects of water intake on urinary markers of hydration and cognition among preadolescents. Methods: A 3-intervention crossover design was used among 9- to 11-y-olds [n = 75 (43 males, 32 females); 58.2 ± 28.5 BMI percentile]. Participants maintained their water intake [ad libitum (AL)] or consumed high (2.5 L/d) or low (0.5 L/d) water for 4 d. The primary outcomes were performance on cognitive tasks requiring inhibition, working memory, and cognitive flexibility assessed using a modified flanker, go/no-go, and color-shape switch tasks, respectively. Secondary outcomes included urine hydration indices [i.e., color, urine specific gravity (USG), osmolality] assessed using 24-h urine collected during day 4 of each intervention. Repeated-measures ANOVAs were used to assess intervention effects. Results: There was a significant difference in hydration across all 3 interventions. Urine color during the low intervention [median (IQR): 6 (2)] was greater than during AL [5 (2)], and both were greater than during the high intervention [18 (0)] (all P ≤ 0.01). Similarly, osmolality [low (mean ± SD): 912 ± 199 mOsmol/kg, AL: 790 ± 257.0 mOsmol/kg, high: 260 ± 115 mOsmol/kg] and USG [low (mean ± SD): 1.023 ± 0.005, AL: 1.020 ± 0.007, high: 1.005 ± 0.004] during the low intervention were greater during AL, and both were greater than during the high intervention (all P ≤ 0.01). USG and osmolality AL values were related to switch task measures (β: 0.21 to -0.31, P < 0.05). Benefits of the high intervention were observed during the switch task, whereby participants exhibited 34% lower working memory cost relative to the low intervention. No significant changes in cognition were observed for the flanker and go/no-go tasks. Conclusions: The water intervention improved urinary markers of hydration and had selective benefits during task switching. Furthermore, children's cognitive flexibility selectively benefits from greater habitual hydration and water intake. This study is registered at clinicaltrials.gov as NCT02816450.
... However, more recently, a series of studies have found a disruption of psychological functioning [4] and driving [5], with a loss of body mass of 1% or less. In addition, in intervention studies, the cognition of children improved after consuming water [6][7][8][9]. ...
... Thus, although plasma osmolality was not assessed, it is unlikely that evidence of tissue dehydration would have resulted. However, although it is unlikely that there are gross changes in tissue dehydration, there must be a mechanism by which a minor loss of body fluid adversely influences mood and cognitive functioning [4][5][6][7][8][9]18] (Figures 1 and 2). ...
Article
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Traditionally, it has been thought necessary to lose 2% of body mass due to dehydration to disrupt functioning, although recently, adverse effects have been reported, with a loss of 0.5%-0.7%. It is, however, unclear whether the response to small reductions in mass reflects dehydration as homeostatic mechanisms are thought to be effective. As psychological responses are most commonly reported, it is strange that the possibility of a placebo response has not been considered. Individuals were therefore subject to a temperature of 30 • C for three hours, and mood and cognition were monitored. To consider changes in hydration status, drinks were compared, differing in their ability to rehydrate due to the presence or absence of electrolytes. The possibility of a placebo response was considered by comparing the response to plain or coloured water. Not drinking was disruptive, although a combination of plain water and electrolyte tended to be the most effective means of preventing a decline in mood, indicating a role for rehydration after a loss of 0.66% body mass. There was, however, also evidence of a placebo response: a combination of plain water and electrolyte tended to be better able to prevent a decline in mood than coloured water and electrolyte.
... This is relevant since some studies suggest that a majority of child athletes may be insufficiently hydrated before they start exercising [43,44]. While there are limited data concerning preexercise hydration status of children from the general population, research suggests that many of them have elevated urine concentration on a given "normal" day across various countries [45][46][47][48][49]. Hydration has also been linked to cognitive performance in children in a number of studies [38,39,50,51]. In a cross-sectional study, Bar-David et al. [38] demonstrated that insufficient hydration, indicated by elevated urinary markers of hydration, was associated with poorer short-term memory performance in children. ...
... In a cross-sectional study, Bar-David et al. [38] demonstrated that insufficient hydration, indicated by elevated urinary markers of hydration, was associated with poorer short-term memory performance in children. Although limited, a handful of interventions have also indicated that providing children with water results in improved cognitive performance [39,50,51]. ...
Article
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In children, maintaining adequate fluid intake and hydration is important for physiological reasons and for the adoption of healthy, sustainable drinking habits. In the Liq.In7 cross-sectional surveys involving 6,469 children (4–17 years) from 13 countries, 60% of children did not meet the European Food Safety Authority (EFSA) adequate intake for water from fluids. Beyond fluid quantity, the quality of what children drink is important for health. In these surveys, the contribution of sugar-sweetened beverages and fruit juices to total fluid intake (TFI) in children exceeded that of water in 6 out of 13 countries. To assess the adequacy of children’s fluid intake, urinary biomarkers of hydration such as urine osmolality, urine specific gravity, and urine color may be used. To date, while there are no widely accepted specific threshold values for urine concentration to define adequate hydration in children, the available literature suggests that many children have highly concentrated urine, indicating insufficient fluid intake. This is worrisome since studies have demonstrated a relationship between low fluid intake or insufficient hydration and cognitive performance in children. Furthermore, results of the Liq.In7 surveys showed that at school – where children spend a significant amount of time and require optimal cognitive performance – children drink only 14% of their TFI. Consequently, it is pertinent to better understand the barriers to drinking water at school and encourage the promotion of water intake through multicomponent interventions that combine educational, environmental, and behavioral aspects to support adequate hydration as well as optimal cognition in children.
... Few studies have sought to investigate the benefits of improved hydration on cognition, and even fewer have focused on children [see 2, 3 for reviews]. Within this limited literature, methods for assessing or modulating hydration have varied across child populations, with the majority focusing either on associations of urinary biomarkers, such as osmolality [4], or acute manipulations whereby hydration is manipulated via water intake and compared to addition-al intake conditions or control groups [5][6][7][8][9][10][11][12]. However, it is important to note that not all studies provide measures of urinary biomarkers. ...
... That is, simply being better hydrated does not necessarily improve cognition in the broad sense, and any improvements might depend on how hydration is manipulated, measured, and what aspects of cognition are measured. Broadly speaking, areas of cognition that have illustrated the benefits of improved hydration and acute water intake include attention [7,[9][10][11][12], short-term memory [4,5,7,9], delayed memory [6], visual search [9,10,12,15], and executive function [14]. However, not all studies have supported a relationship between various hydration mea-sures and cognition, with some reporting null or negative findings for short-term memory [9,11,12,15]. ...
Article
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The effects of optimal and insufficient hydration on human health have received increasing investigation in recent years. Specifically, water is an essential nutrient for human health, and the importance of hydration on cognition has continued to attract research interest over the last decade. Despite this focus, children remain a relatively understudied population relative to the effects of hydration on cognition. Of those studies investigating children, findings have been inconsistent, resulting from utilizing a wide variety of cognitive domains and cognitive assessments, as well as varied hydration protocols. Here, our aim is to create a primer for assessing cognition during hydration research in children. Specifically, we review the definition of cognition and the domains of which it is composed, how cognition has been measured in both field- and laboratory-based assessments, results from neuroimaging methods, and the relationship between hydration and academic achievement in children. Lastly, future research considerations are discussed.
... Consistently, studies have shown that drinking water improves performance in tasks requiring visual attention in both adults and children (Edmonds et al., 2017;Liska et al., 2019;Miljkovic Krecar et al., 2014;Rogers et al., 2001). Positive effects of water consumption have also been found in tasks which measure simple reaction time (Edmonds et al., 2013) and short-term memory in adults (Edmonds et al., 2017) and children (Benton & Burgess, 2009;Fadda et al., 2012). ...
... Straight line A template is used to determine when a sentence deviates from a straight line previous studies which range between 20 and 30 min (Benton & Burgess, 2009;Edmonds et al., 2021). In the second session, the tasks were completed in the same order as in the first session. ...
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Evidence shows that having a drink of water can improve cognitive performance in schoolchildren. This study investigated whether water consumption would improve a range of tasks requiring both cognitive and fine motor skills. Participants were 85 children (37 boys, 48 girls, mean age 10.1 years, SD = 0.6) attending a primary school in the UK. Children completed finger-tapping, bead threading, and handwriting tasks at baseline and test. They were divided into two groups; one group was offered a 500-ml bottle of water after baseline tasks were completed and the other group was not. The drink group were given 5 min to consume the water and they could choose how much to drink. We also recorded the volume of water consumed in order to consider dose response relationships. Participants in both groups were given a 25-min break, during which they could read quietly, before repeating the tasks at test. Results showed that the participants who were given a drink, regardless of volume, had faster handwriting speed at test than those who did not. Correlations between volume drunk and changes in performance from baseline to test showed there was a positive relationship between volume drunk and improvement in finger-tapping speed. These results show that the simple intervention of giving children a drink of water has a beneficial effect on fine motor skills, and handwriting, which is an integral activity in school.
... Few studies have investigated the relationship between dehydration and cognition in children. Evidence from three intervention studies in the United Kingdom corroborate findings among adults, suggesting that drinking water was associated with better scores of attention [13,14], short-term memory [14][15][16], and visual search [13]. However, these studies did not collect biometric measures of hydration status. ...
... However, there was no significant difference in the prevalence of afternoon dehydration among pupils in the water group compared to pupils in the control group. Nonetheless, when the significant impact of water consumption on increasing U sg is considered in light of findings of the relationship between drinking water and cognition from other contexts [13][14][15][16], there is evidence that providing drinking water at school may create a positive impact on pupil learning. ...
Article
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Adequate provision of safe water, basic sanitation, and hygiene (WASH) facilities and behavior change can reduce pupil absence and infectious disease. Increased drinking water quantity may also improve educational outcomes through the effect of hydration on attention, concentration, and short-term memory. A pilot study was conducted to adapt field measures of short-term cognitive performance and hydration, to evaluate levels of hydration, and to investigate the impact of providing supplementary drinking water on the cognitive performance of pupils attending water-scarce schools in rural Mali. Using a cross-over trial design, data were collected under normal school conditions (control condition) on one visit day; on the other, participants were given a bottle of water that was refilled throughout the day (water condition). Morning and afternoon hydration was assessed using specific gravity and urine color. Cognitive performance was evaluated using six paper-based tests. Three percent of pupils were dehydrated on the morning of each visit. The prevalence of dehydration increased in the afternoon, but was lower under the water condition. Although there was a trend indicating drinking water may improve cognitive test performance, as has been shown in studies in other settings, results were not statistically significant and were masked by a “practice effect.”
... Euhydration is important for acute and chronic health; dehydration is a serious health issue associated with a host of physiological problems [2,3], as well as deficits in cognition and increased negative mood [4][5][6]. Dehydration is particularly problematic for children [7,8] and the elderly [9], as the effects of hydration (or dehydration) are pronounced in these populations [10]. Even more broadly, a substantial percentage of the population (at least in the United States) does not meet the minimum guidelines for fluid intake [11][12][13]. ...
Article
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Purpose This study aimed to examine the psychological factors (knowledge, barriers and facilitators) that can contribute to hydration-related behaviors (i.e., fluid intake) in the general population and how these relate to physical health. Methods A structured survey was developed to examine the links between hydration knowledge (29 items), attitudes about hydration (80 items), and fluid intake behavior (8 items) among US adults. Survey data from Phase 1 (n =301, US adults) psychometrically evaluated the items via item analysis (knowledge and fluid behavior) and factor analysis (attitudes). Phase 2 survey data (n =389, US adults and college students) refined and validated the new 16-item hydration knowledge measure, 4-item fluid intake behavior index, and 18-item attitude measure (barriers and facilitators of hydration-related behaviors) alongside indices of physical health (BMI and exercise behaviors). Results Participants had a moderate level of hydration knowledge (Phase 1: 10.91 ± 3.10; Phase 2: 10.87 ± 2.47). A five-factor measure of attitudes which assessed both facilitators (social pressure and attention to monitoring) and barriers (lack of effort, physical barriers and lack of a fluid container) to hydration demonstrated strong internal consistency (αs from 0.75 to 0.90). Attitudes about hydration—most notably barriers to hydration—were associated with indicators of health and with fluid intake behaviors, whereas hydration knowledge was not. Conclusions Increasing hydration knowledge may be necessary for people who hold inaccurate information about hydration, but attitudes about hydration are likely to have a larger impact on fluid intake behaviors and health-related outcomes.
... This knowledge may explain the stronger response of working memory to water consumption in this study. Thus, we support the results of other studies in children [19,20] that an adequate increase in water intake may improve performance in memory tasks. When comparing our results with these studies, we tested short-term memory after a 4-h water intervention period, while others observed a positive effect on short-term memory after acute drinking 300 mL of water or water intervention from morning to afternoon. ...
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There is still little research examining the relationship between water consumption in school and specific cognitive performance. The aim of this cluster-randomized intervention CogniDROP trial was to investigate the short-term effects of drinking water during the morning on executive functions. The participants were from the 5th and 6th grade of a comprehensive school in Germany (14 classes, n = 250, 61.6% boys). The classes were randomly divided into an intervention group (an education on healthy drinking behavior and a promotion of water consumption) and a control group. A battery of computerized tasks (Switch Task, 2-Back Task, Corsi Block-Tapping Task and Flanker Task) was used to test executive functions. Urine color and thirst were evaluated to check the hydration level. Physical activity over the past 24 h was measured using GT3X ActiGraph. A non-linear relationship was observed between the amount of drinking water and executive performance. Consuming water up to 1000 mL (or up to 50% of Total Water Intake) had benefits during memory tasks. Urine color and number of steps on the study day correlated with water consumed. The results suggest that a water-friendly environment supports school-aged children in adequate water intake resulting in better cognitive performance, especially short-term memory.
... Adequate hydration or drinking water is reported to be associated with children's health benefits. For instance, children with normal body weight seem to have better hydration compared with obese [18], while increasing water intake improves cognitive performance [19][20][21][22][23]. Interestingly, a large proportion of children in the United States exhibit elevated urine concentration (assessed via urine osmolality) suggesting that they might be underhydrated [24][25][26]. ...
... It is well known that grave dehydration status is associated with health problems such as confusion, delirium, impaired immune, renal and gastrointestinal functioning. But even mild dehydration states entail negative health consequences: headache, irritability, decrement in physical performance and reduced cognitive function, among others [2,[4][5][6][7][8][9]. These facts gain special importance in children and adolescents considering that it could have implications for both health, sports and school performance [6][7][8][9][10][11][12]. ...
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The achievement of adequate hydration status is essential for mental and physical performance and for health in general, especially in children and adolescents. Nevertheless, little is known about hydration status of this population, mainly due to the limited availability of research tools; thus, the objective of the current study was to adapt and validate our hydration status questionnaire in a Spanish adolescent-young population. The questionnaire was validated against important hydration markers: urine colour, urine specific gravity, haemoglobin, haematocrit and total body water and involved 128 subjects aged between 12–17 years. Water intake was also estimated through a three-day dietary record and physical activity was assessed through accelerometers. Participants completed the questionnaire twice. Water balance and water intake were correlated with urine specific gravity and with total body water content. Water intake obtained by the questionnaire was correlated with results from the three-day dietary record. The intraclass correlation coefficient indicated moderate concordance between both recordings and the Cronbach’s alpha revealed high consistency. The Bland and Altman method indicated that the limits of agreement were acceptable to reveal the reliability of the estimated measures. In conclusion, this is the first time that a questionnaire is valid and reliable to estimate hydration status of adolescent-young populations.
... Our finding that neither mouth rinsing nor mouth drying affected short-term memory offers indirect support to the suggestion that changes in memory performance occur after changes in hydration status, although it should be noted that we did not directly examine this question. Previous research in support of this hypothesis includes findings that large amounts of water are necessary to improve memory performance (Benton & Burgess, 2009;Edmonds et al., 2017;Edmonds & Burford, 2009;Edmonds & Jeffes, 2009;Fadda et al., 2012). Furthermore, previous work has reported direct links between hydration status and memory, with dehydration resulting in poorer working memory (Young & Benton, 2016). ...
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Drinking water is important for health and there is an agreement that drinking water facilitates certain cognitive processes. However, the mechanism underlying the effect of drinking water on cognition is unknown. While attention performance is improved by even a very small drink, memory performance seems to require larger drinks for performance enhancement. This suggests that attention could be affected earlier in the drinking process than memory. We aimed to elucidate further the mechanism involved by investigating the stage during the drinking process influencing performance on cognitive tasks. To this end, we compared mouth rinsing and mouth drying. Mouth rinsing was expected to result in improved attention performance and would suggest that the mechanism responsible is located in the mouth and occurs early in the drinking process, before swallowing. Eighty-seven adults participated in either a treatment (mouth rinsing or mouth drying) or control (no intervention) condition. They were assessed at baseline and 20 min later after intervention on measures of visual attention, short-term memory, subjective thirst and mood. Our results showed that mouth rinsing improved visual attention, but not short-term memory, mood or subjective thirst. Mouth drying did not affect performance. Our results support the hypothesis that different mechanisms underlie the effect of drinking water on different cognitive processes. They suggest that merely sipping water, as opposed to having a large drink, can improve attention.
... Children in the intervention group increased their at-home water consumption by 2·6 ounces/d (76·9 ml/d) more than the control group. In addition to helping limit excess weight gain (9,10) , this increase in water intake could potentially reduce children's risk of inadequate hydration (43) and improve their cognitive functioning (44)(45)(46)(47) . Children in the intervention group also increased their at-home consumption of unsweetened low-or non-fat milk by about 1 ounce/d (30 ml/d) relative to the control group. ...
Article
Objective To evaluate whether a multipronged pilot intervention promoting healthier beverage consumption improved at-home beverage consumption and weight status among young children. Design In this exploratory pilot study, we randomly assigned four childcare centres to a control (delayed-intervention) condition or a 12-week intervention that promoted consumption of healthier beverages (water, unsweetened low- or non-fat milk) and discouraged consumption of less-healthy beverages (juice, sugar-sweetened beverages, high-fat or sweetened milk). The multipronged intervention was delivered via childcare centres; simultaneously targeted children, parents and childcare staff; and included environmental changes, policies and education. Outcomes were measured at baseline and immediately post-intervention and included children’s ( n 154) at-home beverage consumption (assessed via parental report) and overweight/obese status (assessed via objectively measured height and weight). We estimated intervention impact using difference-in-differences models controlling for children’s demographics and classroom. Setting Two northern California cities, USA, 2013–2014. Participants Children aged 2–5 years and their parents. Results Relative to control group children, intervention group children reduced their consumption of less-healthy beverages from baseline to follow-up by 5·9 ounces/d (95 % CI −11·2, −0·6) (–174·5 ml/d; 95 % CI –331·2, –17·7) and increased their consumption of healthier beverages by 3·5 ounces/d (95 % CI −2·6, 9·5) (103·5 ml/d; 95 % CI –76·9, 280·9). Children’s likelihood of being overweight decreased by 3 percentage points (pp) in the intervention group and increased by 3 pp in the control group (difference-in-differences: −6 pp; 95 % CI −15, 3). Conclusions Our exploratory pilot study suggests that interventions focused comprehensively on encouraging healthier beverage consumption could improve children’s beverage intake and weight. Findings should be confirmed in longer, larger studies.
... The aim of this study was to investigate the effects of hydration status, drinking water, and thirst on a range of cognitive processes. Based on the findings of previous studies (Benton & Burgess, 2009;Edmonds & Jeffes, 2009, Booth et al., 2012, Edmonds et al. 2013, Rogers et al., 2001, Benton et al., 2016, we expected performance for sustained attention and executive function tests to be positively affected by water consumption (Hypothesis 1). It was predicted that since water consumption has positive effects on typical cognitive processing tests, this should extend to judgment and decision-making tasks (Hypothesis 2) and that attention and executive performance scores (here: set shifting) correlate with judgement and decision-making tasks (Hypothesis 3). ...
Article
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Previous research has shown that dehydration and water supplementation affect mood and cognitive performance in both adults and children on a variety of tasks that assess memory, attention, executive function, and speeded responses. Given the varied effects of water on cognition, this study explored potential effects of water supplementation, hydration status, and thirst on thinking and decision-making tasks. 29 adult participants undertook a battery of cognitive tests on two separate occasions after having fasted from the previous night. On one occasion, they were offered 500 ml of water to drink prior to testing. Measures of urine osmolality confirmed the group-level effectiveness of the dehydration manipulation. Water supplementation was found to improve performance on tasks measuring cognitive reflection in judgement and decision-making. This increase in performance was associated with differences in tasks implicated in inhibition processes. Drinking water after a 12-h dehydration period increased performance in judgement and decision-making tasks, and this was not explained by differences in subjective thirst or attentiveness.
... This increases susceptibility to hypohydration and subsequent physiological and psychological impairments. Fluid intake and euhydration are essential for physiological function and health, in addition to cognitive function and mood in both children [140,141] and adults [142]. Hypohydration attenuates SRs in both populations, with notable thermoregulatory impact on children due to their already lower sweating responses for a given workload. ...
Article
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Predicted global climate change, including rising average temperatures, increasing airborne pollution, and ultraviolet radiation exposure, presents multiple environmental stressors contributing to increased morbidity and mortality. Extreme temperatures and more frequent and severe heat events will increase the risk of heat-related illness and associated complications in vulnerable populations, including infants and children. Historically, children have been viewed to possess inferior thermoregulatory capabilities, owing to lower sweat rates and higher core temperature responses compared to adults. Accumulating evidence counters this notion, with limited child–adult differences in thermoregulation evident during mild and moderate heat exposure, with increased risk of heat illness only at environmental extremes. In the context of predicted global climate change, extreme environmental temperatures will be encountered more frequently, placing children at increased risk. Thermoregulatory and overall physiological strain in high temperatures may be further exacerbated by exposure to/presence of physiological and environmental stressors including pollution, ultraviolet radiation, obesity, diabetes, associated comorbidities, and polypharmacy that are more commonly occurring at younger ages. The aim of this review is to revisit fundamental differences in child–adult thermoregulation in the face of these multifaceted climate challenges, address emerging concerns, and emphasize risk reduction strategies for the health and performance of children in the heat.
... Previously, various intervention studies have reported that the mood and cognition of children benefited from drinking water. For example, in the afternoon when 8-y-old children who had been in school all day, and may have drunk little, were given a drink of water this improved memory (8). Similarly, after 7-9-y-old children had drunk water, measures of attention and memory improved (9). ...
Article
Plasma and serum osmolality are often used to indicate hydration status; however, as serum osmolality varies very little over a wide range of urine osmolality, it has been assumed that there is little likelihood of either dehydration or hyperhydration. That is, adequate hydration is maintained by homeostatic mechanisms when you respond to thirst with an appropriate pattern of drinking. It is unsurprising, therefore, that there have been few studies of the consequences of everyday variations in hydration status. It is possible that a loss of body mass <2% is disruptive but not necessarily because of reduced hydration status. Indeed, many homeostatic mechanisms (e.g. autonomic nervous system, cortisol, vasopressin, renin-angiotensin aldosterone system) have influences in addition to maintaining fluid amounts.
... Adequate hydration or drinking water is reported to be associated with children's health benefits. For instance, children with normal body weight seem to have better hydration compared with obese [18], while increasing water intake improves cognitive performance [19][20][21][22][23]. Interestingly, a large proportion of children in the United States exhibit elevated urine concentration (assessed via urine osmolality) suggesting that they might be underhydrated [24][25][26]. ...
Article
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While daily hydration is best assessed in 24-h urine sample, spot sample is often used by health care professionals and researchers due to its practicality. However, urine output is subject to circadian variation, with urine being more concentrated in the morning. It has been demonstrated that afternoon spot urine samples are most likely to provide equivalent urine concentration to 24-h urine samples in adults. The aim of the present study was to examine whether urine osmolality (UOsm) assessed from a spot urine sample in specific time-windows was equivalent to 24-h UOsm in free-living healthy children. Among 541 healthy children (age: 3–13 years, female: 45%, 77% non-Hispanic white, BMI:17.7 ± 4.0 kg m⁻²), UOsm at specific time-windows [morning (0600–1159), early afternoon (1200–1559), late afternoon (1600–1959), evening (2000–2359), overnight (2400–0559), and first morning] was compared with UOsm from the corresponding pooled 24-h urine sample using an equivalence test. Late afternoon (1600–1959) spot urine sample UOsm value was equivalent to the 24-h UOsm value in children (P < 0.05; mean difference: 62 mmol kg⁻¹; 95% CI: 45–78 mmol kg⁻¹). The overall diagnostic ability of urine osmolality assessed at late afternoon (1600–1959) to diagnose elevated urine osmolality on the 24-h sample was good for both cutoffs of 800 mmol kg⁻¹ [area under the curve (AUC): 87.4%; sensitivity: 72.6%; specificity: 90.5%; threshold: 814 mmol kg⁻¹] and 500 mmol kg⁻¹ (AUC: 83.5%; sensitivity: 75.0%; specificity: 80.0%; threshold: 633 mmol kg⁻¹). These data suggest that in free-living healthy children, 24-h urine concentration may be approximated from a late afternoon spot urine sample. This data will have practical implication for health care professionals and researchers.
... As outlined earlier, provision of safe drinking water at schools has been linked to lower student school absenteeism and higher learning due to significant reductions in the diarrheal disease burden impacting students across the developing world (O'Reilly, et al., 2008;Barde & Walkiewicz, 2014). Studies have also shown that drinking water can improve students' readiness to learn by increasing the level of cognitive functioning (Edmonds, 2009;D'Anci, et al., 2006;Benton & Burgess, 2009). For drinking water to be considered safe, it must come from an improved source; that is piped water supply, protected well/supply, truck/cart, rainwater, or packaged bottled water. ...
Technical Report
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This report provides a snapshot of the basic education system in Tanzania using a combination of data collected from the Service Delivery Indicators (SDI) Surveys in 2014 and 2016, and data from SABER Service Delivery 2016 (i.e. Development-World Management Survey, Classroom Observation). Using data collected through direct observations, unannounced visits, and tests from primary schools in Tanzania, the report highlights strengthens and weaknesses of the education system and identifies specific bottlenecks that inhibit student learning. One of the main contributions of this report is to provide information on different domains which are crucial for learning but have not been examined previously due to lack of data such as quality of teaching practices and quality of school management. In addition, this report provides guidance to the Government on student, teacher and school level factors associated with learning outcomes, which are intended to help the Government to make informed choices on where to direct resources to further raise learning and reduce inequities in the basic education sector. Despite the improvement in the learning outcomes and the progress in terms of access to education during the past ten years, there is still a learning crisis in Tanzania. These poor learning outcomes reflect a somewhat weak provision in service delivery, especially in terms of (i) teaching practices, (ii) school management, and (iii) school inputs.
... The effects of dehydration are not only acute conditions like heatstroke, but also increased risks of kidney stones, chronic kidney disease, urinary tract infections, cardiovascular diseases, and metabolic disease [4]. Furthermore, a recent report found that mild dehydration affected mood and cognitive functions [5][6][7]. During the past decade, considerable public attention has focused on the importance of adequate hydration. ...
Article
Full-text available
Increased hydration is recommended as healthy habit with several merits. However, supportive data are sparse. To assess the efficacy of increased daily water intake, we tested the effect of water supplementation on biomarkers in blood, urine, and saliva. Twenty-four healthy Japanese men and 31 healthy Japanese women with fasting blood glucose levels ranging from 90–125 mg/dL were included. An open-label, two-arm, randomized controlled trial was conducted for 12 weeks. Two additional 550 mL bottles of water on top of habitual fluid intake were consumed in the intervention group. The subjects drank one bottle of water (550 mL) within 2 h of waking, and one bottle (550 mL) 2 h before bedtime. Subjects increased mean fluid intake from 1.3 L/day to 2.0 L/day, without changes in total energy intake. Total body water rate increased with associated water supplementation. There were no significant changes in fasting blood glucose and arginine vasopressin levels, but systolic blood pressure was significantly decreased in the intervention group. Furthermore, water supplementation increased body temperature, reduced blood urea nitrogen concentration, and suppressed estimated glomerular filtration rate reduction. Additionally, existence of an intestinal microbiome correlated with decreased systolic blood pressure and increased body temperature. Habitual water supplementation after waking up and before bedtime in healthy subjects with slightly elevated fasting blood glucose levels is not effective in lowering these levels. However, it represents a safe and promising intervention with the potential for lowering blood pressure, increasing body temperature, diluting blood waste materials, and protecting kidney function. Thus, increasing daily water intake could provide several health benefits.
... Dehydration is also closely related to coronary heart disease, kidney disease 5 , body fitness index, cognitive performance, and psychological and mood disorders 6 , which can lead to lower productivity 7 . Adequate water consumption is therefore essential for preventing these conditions, and increased drinking water consumption has been found to positively improve mood, vigilance level, brain memory performance, and attention during task completion [8][9][10][11][12][13] . ...
... The consequences of this dehydration are severe; consuming sufficient water not only helps prevent obesity but also is vital for children's growth, physical health, and mental well-being (Muckelbauer et al. 2009;Armfield et al. 2013;Masento et al. 2014). Water also has important implications for children's academic performance because it bolsters children's memory, attention, and cognition (Benton and Burgess 2009;Edmonds and Burford 2009;Edmonds and Jeffes 2009). As a result, the WHO has repeatedly stated that encouraging children to drink more water is a global priority (World Health Organization 2012, 2016. ...
Article
Full-text available
We collaborated with UNICEF and launched a field experiment in Panama to test the effectiveness of communicating different means-goal associations in promoting children's consumption of water. This research is the first to examine whether interventions that operate by highlighting strong means-goal associations have real consequences outside the lab in the noisy real world. Also important, means-goal associations have previously been examined exclusively among adults. Because prior research reveals that children and adults often respond differently to persuasion attempts, important theoretical insight is gained by investigating whether children's use of a means can be increased by interventions that highlight means-goal associations. This research is also the first to explore whether highlighting means-goal associations of different strengths can produce not only positive but also potentially negative effects. Together , the current research advances the extant understanding of the divergent impact of means-goal associations on behavior, uncovers an intervention that increases children's consumption of water, and provides valuable managerial implications as well as food for thought for future research.
... R https://doi.org/10.1038/s41415-020-2555-x functioning, limit excess weight gain and prevent dehydration, urinary tract infection etc. 3,4 Consuming water instead of beverages with added sugars can also prevent the occurrence of dental caries in children. 5 The concept started in government schools in Kerala state, with bells at 11 am, 2 pm and 3.30 pm and is now embraced by other states including Karnataka, Telegana and Orissa. ...
... Inadequate WaSH circumstances have been said to be connected to poor academic performance in children by contributing to absenteeism and reduced cognitive capacities (Alexander et al., 2013;O'Reilly et al., 2008;Bar-David et al., 2005;Bartlett, 2003;Benton & Burgess, 2009). In collaboration, Bartlett outlined the influence of filthy environments and diarrheal disease on child malnutrition as well as mental and social development, including school achievement levels, working memory, and behavioral issues (Bartlett, 2003). ...
Article
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Studies have documented that poor WaSH is accountable for several cases of diarrhea globally, resulting in millions of unnecessary deaths each year, particularly among children, and most notably in underdeveloped countries where poor knowledge and practice of WaSH have been well documented. Therefore, the work prioritizes evaluation of WaSH practice among students in secondary school in Ijebu Ode, in light of the emergence of COVID-19, which has further highlighted the essence of WaSH practice, especially in our schools. A descriptive cross-sectional approach was adopted in the conduct of the investigation, wherein data was sourced from 60 students selected through random numbers from six randomly selected secondary schools (three public and three private), representing a total student population of 360. The data collected through structured questionnaire and personal interview were computed and analyzed descriptively using Microsoft Excel and Statistical Software for Social Scientist (version 20). Findings indicated that majority of the students in Ijebu Ode have adequate knowledge (78.9%) and inadequate practice (45.6%) on WaSH, and thus, concluded that whereas the participants have adequate knowledge on WaSH, it however did not translate into an actual practice. Hence, a need for an intensive effort that will facilitate adequate WaSH practices among the school students through the availability and accessibility of appropriate WaSH resources, with school and home schedules for WaSH practice.
... More susceptible to dehydration than adults, children depend on adults for hydration (Bar-Or, 1998;Bar-Or et al., 1980;D'Anci et al., 2006). Mild dehydration can affect cognitive development such as decreased visual attention and short-term memory (Benton & Burgess, 2009;D'Anci et al., 2006;Edmonds & Burford, 2009;Edmonds & Jeffes, 2009). To help ensure proper hydration, the US Department of Agriculture implemented the National School Lunch Program in 2011 and required participating schools to provide water at mealtime (section 9. [42 US code § 1758]) (US Department of Agriculture [USDA], 2011). ...
Article
The study goal was to better understand the risks of elevated copper levels at US schools and childcare centers. Copper health effects, chemistry, occurrence, and remediation actions were reviewed. Of the more than 98,000 schools and 500,000 childcare centers, only 0.2% had copper water testing data in the federal Safe Drinking Water Information System database. Of the facilities designated public water systems, about 13% had reported an exceedance. Schools that were not designated a public water system (PWS) also had exceedances. Few studies document levels in schools and childcare centers. Widely different sampling and remedial actions were reported. Flushing contaminated water was the most evaluated remedial action but was unreliable because copper quickly rebounded when flushing stopped. Building water treatment systems have been used, but some were not capable of making the water safe. The health risk was difficult to determine due to the limited occurrence data and lack of best management practice studies. A national drinking water testing campaign and field studies are recommended.
... 1,2,6 Students who had higher academic grades were also more likely to drink water three or more times per day, adding evidence to support the connection between adequate hydration and improved cognitive function, memory, and attention. 16 Drinking milk one or more times per day was not statistically significant for any grade category. However, results from previous studies have indicated that drinking milk is associated with academic grades. 2 The physical activity findings in our study also corroborate previous research. ...
Article
Purpose We examined associations between academic grades and positive health behaviors, individually and collectively, among U.S. high school students. Design Cross-sectional study design. Setting Data were from the 2017 national Youth Risk Behavior Survey. Response rates were 75% for schools, 81% for students, and 60% overall (n = 14,765 students). Subjects Youth in grades 9th–12th. Measures We focused on youth behaviors that can prevent or delay the onset of chronic health conditions. Seven dietary, 3 physical activity, 2 sedentary screen time, and 4 tobacco product use behaviors were assessed. Variables were dichotomized (0/1) to indicate that a score was given to the positive health behavior response (e.g.,, did not smoke cigarettes = 1). A composite score was created by summing each positive health behavior response among 16 total health behaviors. Analysis Multivariable logistic regression analyses for each individual health behavior, and a multivariable negative binomial regression for the composite score, were conducted with self-reported academic grades, controlling for sex, grade in school, race/ethnicity, and body mass index (BMI) categories. Results Controlling for covariates, students who reported mostly A’s had 2.0 ( P < .001) more positive health behaviors; students who reported mostly B’s had 1.3 ( P < .001) more positive health behaviors; and students who reported mostly C’s had .78 ( P < .001) more positive health behaviors, compared to students who reported mostly D’s/F’s. Conclusions Higher academic grades are associated with more positive individual and cumulative health behaviors among high school students. Understanding these relationships can help inform efforts to create a healthy and supportive school environment and strive for health equity.
... Inadequate hydration can have negative impacts on physical health and cognitive performance [47]. One study found children with higher, more recent fluid intake had better concentration and memory scores on standardized tests [48], which is consistent with results from other studies [49,50]. In order to provide guidance for fluid requirements, The Panel on Dietary Reference Intakes for Electrolytes and Water of the National Academy of Medicine (formerly the Institute of Medicine) determined adequate intake (AI) levels, but recognized that fluid needs can be highly variable among different people, based on individual factors like diet, activity level, and climate [51]. ...
Article
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Purpose of Review Improving beverage patterns is important for promoting the health of children and adolescents. Food preferences can begin developing at a young age; thus, children and adolescents should be provided healthy beverages in accordance with current recommendations. The purpose of this review is to identify and summarize existing beverage recommendations for children and adolescents. This review also discusses the health impacts of beverages and how beverage consumption has changed among children and adolescents over time. Recent Findings The mean number of calories that children and adolescents are consuming from beverages on a given day has declined in recent years. However, sugar-sweetened beverages (SSB) are the primary source of added sugars in this population. Therefore, SSB consumption remains a concern, and reducing the intake of SSB is still considered a top priority for helping to improve dietary quality. Summary This review uniquely compiles recommendations into one convenient table for the entire age range of 0–19 years and includes recommendations that can be more adequately individualized. Beverage categories where beverage recommendations from authoritative sources are lacking have also been identified. Potential methods that can be implemented to improve beverage patterns and current public policy recommendations have been discussed to provide actionable steps that public health professionals can utilize in practice. The comprehensive table of beverage recommendations could be useful for professionals promoting the health of children and adolescents in research, clinical, and public health settings.
... Zaobserwowano także, że w szkołach umożliwiających swobodny dostęp do wody pitnej (np. takich, gdzie pozwalano na przynoszenie butelek z wodą i picie jej w klasie) dodatkowe spożycie wody (300 ml) w wybranych dniach w grupie dzieci 8-letnich doprowadziło do znacznej poprawy koncentracji uwagi w porównaniu z dniami, kiedy to dzieci obywały się bez dodatkowego spożycia wody [37]. P. Booth i wsp. ...
... Some authors state the importance of water access in schools to children's cognitive performance, mainly for short-term memory exercises ( Bar-David, et al., 2005;Benton & Burgess, 2009;Fadda, et al., 2012). Ortiz-Correa et al. (2016) found the positive and significant effects of schooling, where children who live in houses with indoor plumbing complete 0.7 school years more than those without it. ...
Article
Full-text available
The aim of the study was to analyze the variations in students’ performance rates in schools int the Jequitinhonha and Mucuri Valleys, in the Brazilian state of Minas Gerais, contemplated by the School Cistern Program. The survey of the schools contemplated by the Program was carried out with documental research of spreadsheets provided by the Brazilian Semi-arid Articulation. The data about school failure and dropout rates were collected from the Instituto Anísio Teixeira (INEP), and made available on the Qedu website. The non-parametric Wilcoxon test was used for testing averages. As means of school performance rates in the periods before and after the installation of the cistern in schools, they were not different. Thus, the expectation of an improvement in school performance rates through the Program was not evident. Thus, the present study shows that there are factors that still need to be studied and treated for the School Cistern Program to reach its objective of improving school performance rates in the region of the Jequitinhonha and Mucuri valleys.
... Some authors state the importance of water access in schools to children's cognitive performance, mainly for short-term memory exercises ( Bar-David, et al., 2005;Benton & Burgess, 2009;Fadda, et al., 2012). Ortiz-Correa et al. (2016) found the positive and significant effects of schooling, where children who live in houses with indoor plumbing complete 0.7 school years more than those without it. ...
... • Three studies that examined the effect of hydration on school children's cognition (Benton & Burgess, 2009;Edmonds & Burford, 2009;Edmonds & Jeffes, 2009) reported mixed results and high heterogeneity in the methods used. ...
Technical Report
Full-text available
https://www.who.int/publications/i/item/9789240015241
... Increasing the amount of fluid consumed might reverse negative effects of dehydration on cognition. Drinking water has been shown to improve performance in children (Benton & Burgess, 2009;Booth, Taylor, & Edmonds, 2012;Edmonds & Burford, 2009;Edmonds et al., 2017;Edmonds & Jeffes, 2009;Fadda et al., 2012), and adults (Benton et al., 2016;Edmonds, Crombie, Ballieux, Gardner, & Dawkins, 2013;Edmonds, Crombie, & Gardner, 2013a, 2013b, even where there is only minimal dehydration (loss of <1% body mass) (Benton et al., 2016). ...
Article
Objective : To systematically examine the effect of dehydration on health outcomes, identify associated financial costs and consider impacts on cognitive performance in older adults. Design : A systematic review of English-language articles via OVID using MEDLINE, PsychINFO, EMBASE, and others, to March 2018. Included studies examined the relationship between hydration status and health, care costs or cognitive outcome. Setting : Cross sectional and cohort data from studies reporting on dehydration in older adults. Participants : Adults aged 60 years and older. Measurements : Independent quality ratings were assessed for all extracted articles. Results : Of 1684 articles screened, 18 papers (N = 33,707) met inclusion criteria. Participants were recruited from hospital settings, medical long-term care centres and the community dwelling population. Data were synthesised using a narrative summary. Mortality rates were higher in dehydrated patients. Furthermore, health outcomes, including frailty, bradyarrhythmia, transient ischemic attacks, oral health and surgery recovery are linked to and worsened by dehydration. Length of hospital stay, either as a principal or secondary diagnosis, is greater in those with dehydration, compared to those who are euhydrated. Finally, neurocognitive functioning may be impacted by dehydration. There are issues with study design, inconsistency in hydration status measurement and different measures used for outcome assessment. Conclusion : Dehydration in older people is associated with increased mortality, poorer course of illness and increased costs for health services. In addition, there is some, but sparse evidence that dehydration in older people is linked to poorer cognitive performance. Intervention studies should test strategies for reducing dehydration in older adults.
... R https://doi.org/10.1038/s41415-020-2555-x functioning, limit excess weight gain and prevent dehydration, urinary tract infection etc. 3,4 Consuming water instead of beverages with added sugars can also prevent the occurrence of dental caries in children. 5 The concept started in government schools in Kerala state, with bells at 11 am, 2 pm and 3.30 pm and is now embraced by other states including Karnataka, Telegana and Orissa. ...
Article
Full-text available
... R https://doi.org/10.1038/s41415-020-2555-x functioning, limit excess weight gain and prevent dehydration, urinary tract infection etc. 3,4 Consuming water instead of beverages with added sugars can also prevent the occurrence of dental caries in children. 5 The concept started in government schools in Kerala state, with bells at 11 am, 2 pm and 3.30 pm and is now embraced by other states including Karnataka, Telegana and Orissa. ...
... Drinking water at schools makes up a significant part of their daily water intake (Kaushik et al., 2007), and thus has a great impact on their growth, development, cognitive function, and school performance (Al Osman et al., 2019;CDC, 2008;Fadda et al., 2012). Easily accessible drinking water at schools can increase students' water intake (Kaushik et al., 2007;Patel et al., 2011), which is conducive to the enhancement of their short-term memory (Benton and Burgess, 2009) and improvement of visual attention (Edmonds and Burford, 2009;Edmonds and Jeffes, 2009). However, students might be exposed to pathogenic microorganisms from unsafe drinking water supplies, leading to outbreaks of water-borne diseases (Park et al., 2018). ...
Article
Background Drinking water quality for children should be higher than adults due to both behavioral and physiological factors. Thus, to provide enough, safe, and easily accessible drinking water for children at schools, the Shanghai Municipal Government initiated a direct-drinking water project in 2013. However, there has been no study so far to assess the quality of direct-drinking water or to investigate its risk factors in Shanghai elementary and middle schools. Methods In the present study, we selected direct-drinking water equipment from 183 elementary and middle schools (17% of total) in Shanghai to detect the colony-forming units (CFU), residual chlorine, chemical oxygen demand (COD), and turbidity of water samples, and analyzed the risk factors of its quality using both simple and multiple linear regression analysis. Results Results showed that the CFU, residual chlorine, COD, and turbidity of direct-drinking water in Shanghai elementary and middle schools ranged from 300 cfu/mL, <LOD-0.670 mg/L, 0.090–2.710 mg/L, and 0.100–2.050 NTU, respectively. The results of simple linear regression analysis indicated that the CFU of direct-drinking water significantly increased when water temperature was between 25 and 60 °C (β = 19.862, p = 0.030), but it was decreased at 60–100 °C (β = - 16.387, p = 0.046). Additionally, the CFU was higher in elementary schools than middle schools, which was also affected by faucet type and water treatment technology (p = 0.006, 0.012 and 0.042, respectively). The residual chlorine in direct-drinking water significantly increased when there was no toilet within 10 m (β = 0.012, p = 0.045). The COD of direct-drinking water was significantly higher in rural areas and in warm water, compared to urban areas (p = 0.033) and room temperature water (p = 0.000), respectively. The turbidity of direct-drinking water was significantly higher in urban areas and water using UF/MF technology, compared to rural areas (p = 0.030) and RO technology (p = 0.009), respectively. The results of multiple linear regressions analysis drew the same conclusions. Conclusions In order to improve the quality of direct-drinking water, the equipment should be as far away from toilet as possible and direct-drinking water should be kept at room temperature or heated at high temperature (over 60 °C). Furthermore, sanitary standards of direct-drinking water quality and relevant laws and regulations should be established and implemented as soon as possible. Our study demonstrates that it is critical to improve direct-drinking water quality and ensure the safety of drinking water in elementary and middle schools in Shanghai.
... Furthermore, results of a study implemented among 47 adults showed that water consumption affected performance in the letter cancellation task, which investigated the cognitive ability of visual attention, but not mood [25]. Similarly, studies conducted among children reported that even under conditions of mild dehydration, consuming a range from 300 to 1000 mL of water resulted in better cognitive performance [26][27][28]. However, some studies have obtained controversial conclusions. ...
Article
Full-text available
Water is indispensable to keeping the functions of the human body working properly, including that of the brain. The purpose of this research was to explore the impacts of water supplementation on cognitive performance and mood, and to determine the optimum amount of water to alleviate detriments of dehydration after 12 h water restriction. A randomized controlled trial was implemented among 64 young adults from Baoding, China. Fasting overnight for 12 h, and at 8:00 a.m. on day 2, osmolality of first morning urine and blood, cognitive performance, and mood were assessed as the dehydration test. Then, participants were randomly separated into four groups: water supplementation groups (WS groups 1, 2, and 3 with 500, 200, and 100 mL purified water, respectively) and no water supplementation group (NW group). Participants in WS groups were instructed to drink the water within 10 min, while those in NW group drank no water. After 90 min, the same measurements were taken as the rehydration test. There was significant interaction between TIME and VOLUME in thirst when comparing dehydration with rehydration tests (F = 6.172, p = 0.001). Significant thirst reductions were found in WS group 1 and WS group 2 (p = 0.003; p = 0.041), and a significant increase was found in the NW group (p = 0.039). In the rehydration test, significant interactions between TIME and VOLUME were found in scores of anger, fatigue, and TMD (total mood disturbance) (F = 3.815, p = 0.014; F = 10.429, p < 0.001; F = 5.246, p < 0.001), compared to the dehydration test. Scores of anger were only decreased in WS group 2 (p = 0.025), and scores of fatigue and TMD decreased in WS group 1 and WS group 2 (all p < 0.05). Significant interaction between TIME and VOLUME was only found for operation span test scores (F = 2.816, p = 0.047), with scores being only higher in WS group 1 in the rehydration test compared to the dehydration test (p = 0.003). Comparing WS group 1 and WS group 2, scores of thirst, fatigue, and TMD did not differ significantly (p > 0.05). Water supplementation improved working memory and attenuated anger, fatigue, and TMD. A small amount of water (200 mL) was sufficient to attenuate thirst, anger, fatigue, and TMD of young adults, but the larger volume (500 mL) appeared to be necessary to improve working memory. The amount of 500 mL was the optimum volume to improve the cognitive performance and mood among young adults.
Article
Background Recent findings suggest a possible role of diet, particularly nutrient in- takes and dietary patterns, in the prevalence of mild cognitive impairment (MCI); few studies, how- ever, have been explicitly devoted to the relationship between dietary habits and MCI. Objectives We aimed to explore the association between dietary habits, including meal timing, and MCI among older Chinese adults. Methods This cross-sectional study involved data collected at the baseline of the Tianjin Elderly Nutrition and Cognition Cohort (TENCC) study, in which 3,111 community-dwelling older adults (326 MCI patients and 2,785 non-MCIs) from a rural area of Tianjin, China, were recruited. In March 2018 to June 2019, all participants underwent a detailed neuropsychological evaluation that allowed for psychometric MCI classification. Information on self-reported dietary behaviors was gathered via face-to-face interviews. Crude and multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models. Results In the multivariable-adjusted models, eating breakfast 4 to 6 times per week (vs. ≤3 times per week, OR: 0.45; 95% CI: 0.26, 0.75), drinking water before breakfast (yes vs. no, OR: 0.64; 95% CI: 0.51, 0.82), consuming water ≥1.5L per day (vs. <1.5L per day, OR: 0.64; 95% CI: 0.51, 0.82), and having lunch after 12:00 (vs. before 12:00, OR: 0.59; 95% CI: 0.47, 0.75) were associat- ed with decreased risk of MCI. Participants who consumed higher amounts of cooking oil were at a higher risk of MCI (moderate vs. low, OR: 1.42; 95% CI: 1.04, 1.92; high vs. low, OR: 1.40; 95% CI: 1.07-1.83). Conclusion This study suggests that dietary habits, including breakfast frequency, daily water consumption, cooking oil consumption, and meal timing, may be associated with the risk of MCI. If replicated, these findings would open new possibilities of dietary interventions for MCI.
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Diarrhea, soil-transmitted helminth (STH) infection, and malnutrition threaten the lives of millions of children globally but particularly in the Global South, where inadequate water, sanitation, and hygiene (WaSH) drive disease risk. The aim of our study was to identify environmental and behavioral risk factors of these diseases among schoolchildren in Metro Manila, Philippines. We analyzed data from a multistage cluster sample of grade 5-10 students to investigate WaSH facilities and hygiene practices. Outcomes were self-reported diarrhea and STH infection and observed malnutrition (stunting, undernutrition, over-nutrition); we used logistic regression models to explore correlates. We included 1,558 students from 15 schools in 3 cities. Over 14% (212) of students experienced diarrhea only, 29.7% (438) experienced STH infection only, and 14% (207) experienced both diarrhea and STH infection. Over 15% (227) of students were stunted, ∼6% (87) were undernourished, and 21% (306) were over-nourished. While diarrhea was associated with poor handwashing, avoiding school restrooms, and lack of a restroom cleaning policy, STH infection was associated with students’ dissatisfaction with school restrooms. Risk of having both diarrhea and STH infection increased when school restrooms lacked water or were unclean. Being only stunted was associated with diarrhea, while being both stunted and undernourished was associated with STH infection. These findings demonstrate that adequate water supply and cleanliness of school WaSH facilities must be achieved and maintained to prevent disease. Future school-based WaSH interventions are recommended to provide clean WaSH facilities that have water, promote handwashing, and discourage avoidance of school toilets.
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Dehydration (water loss >2.0% of body weight) has significant negative effects on physical and mental performance. In two studies the effects of minor hypo-hydration (water loss <1.0% of body weight) on CNS function, mood and cardiovascular functioning were measured. Study 1: On two mornings twelve male participants were exposed to a temperature of 30 °C for four hours and either did or did not drink two 150 ml glasses of water during that time. Study 2: Fifty-six (25 M) individuals were exposed to the same 30 °C environment and randomly allocated to either drink (2 × 150 ml) or not drink. When not given water 0.59% (Study 1) and 0.55% (Study 2) bodyweight was lost. Participant’s heart rate variability (HRV) was measured, and they rated their thirst and mood. In study 1, participants participated in an fMRI protocol during which they completed a modified version of the Paced Auditory Serial Addition Test (PASAT), at the end of which they rated its difficulty. Decreases in fMRI BOLD activity in the orbito-frontal cortex, ventral cingulate gyrus, dorsal cingulate cortex, hypothalamus, amygdala, right striatum, post-central gyrus and superior parietal cortex were observed when participants were hypo-hydrated. These deactivations were associated with reduced HRV, greater perceived effort, and more anxiety. In study 2 declines in HRV were found to mediate the effect of hypo-hydration on ratings of anxiety. These data are discussed in relation to a model that describes how autonomic regulatory and interoceptive processes may contribute to the affective consequences of minor hypo-hydration.
Article
BACKGROUND Youth water consumption is inadequate. Increasing adolescent water consumption could support decreased dental caries and body mass index (BMI). Most schools are required to provide free, potable water. However, there is evidence that schools' self‐reported compliance data overestimate access to water in schools. We tested the feasibility of using student citizen scientists to collect high quality observational data about water sources in schools. METHODS We trained 12 teams of high school students to use a validated photo‐evidence protocol to photograph and submit data on water sources in elementary and secondary schools. We surveyed students and advisors to assess student learning, advisor burden, and project feasibility. RESULTS Students submitted data for 325 water sources across 40 racially and economically diverse schools. We were able to use 99% of the student‐submitted photographs to measure water source wear, cleanliness, accessibility, and flow. The majority of students (72%, N = 70) spent under 2 hours photographing each school. The majority of students and advisors felt the project was valuable and feasible. CONCLUSIONS High school students can use a photographic method to collect data for analysis, and understand access to water in schools. This is a feasible, scalable, cost‐effective method to gather valid water source data.
Article
Objective Engaging in a healthy diet and positive lifestyle behaviors have been shown to improve cognitive functioning in children and older adults, however, few have examined these factors in college-aged students. Participants: A diverse sample of 115 college students were recruited on two university campuses. Method: Completed computerized cognitive testing and an online survey about diet and lifestyle behaviors. Results: All analyses were conducted with Pearson’s correlations. Higher fruit consumption was correlated with better visual memory scores. Higher seafood consumption was correlated with better learning performance. Increased fast food consumption was correlated with poorer executive functioning in resident students and poorer visual memory performance in commuter students. Increased fluid intake on testing day was correlated with better visual memory and better verbal memory performance. Conclusions: Behavioral changes such as increasing hydration, eating more fruit and fish, and eating less fast food may improve cognitive performance in college students.
Article
Issue addressed: Across Australia there are inconsistent and varying guidelines or 'recommendations' across a number of jurisdictions for the protection of school children from heat-related consequences, yet there is no national policy for heat protection in school settings. The aim of this study was to determine public perceptions of the efficacy of implementing a heat protection policy for Australian schools. Methods: A sample of public perceptions were drawn upon from public comments posted on a national Australian Broadcasting Corporation (ABC) news article on the proposed heat protection policy. Public comments were analysed using a social-ecological model thematic content analysis. Results: Themes that emerged to support a national heat protection policy for schools included: protection from the consequences of extreme heat, reliance of children on adult/school decisions and utilising modern knowledge/technology advancements. In contrast, criticism emerged relating to the importance of having resilient children, air conditioning costs, perceived over-regulation and heat exposure being a lifestyle choice in some contexts. Conclusions: Overall, this study provides support for the introduction of a national heat protection policy with a number of key considerations identified for implementation to benefit and protect Australian school children. SO WHAT?: As a number of the heat guidelines are developed by individual organisations with differing messages, determining the public efficacy of comprehensive heat protection strategies can help lead to the development of policy for a widespread and consistent heat protection program across Australian schools.
Article
Objective Drinking water instead of beverages with added sugar can help prevent obesity and cavities and promote overall health. Children spend much of their day in school, where they have variable access to drinking water. In 2010, federal and state law required California public schools to provide free potable water to students in areas where meals are served and/or eaten. The current study aims to identify factors associated with an excellent drinking water culture in schools. Design A qualitative assessment of barriers and facilitators to providing excellent water quality and access in a purposive sample of California schools. In-depth interviews with key informants were conducted using a snowball sampling approach, after which data were analysed using both inductive and deductive methods. Setting California public elementary, middle/junior and high schools. Participants Knowledgeable individuals involved in initiatives related to school drinking water accessibility, quality or education at each selected school. Results Thirty-four interviewees participated across fifteen schools. Six themes emerged as prominent facilitators to a school’s success in providing excellent water access to students: active and engaged champions, school culture and policy, coordination between groups, community influences, available resources and environmentalism. Conclusions While policy is an important step for achieving minimum standards, resources and interest in promoting excellence in drinking water access and quality can vary among schools. Ensuring that schools have dedicated staff committed to advancing student health and promoting the benefits of water programs that are more salient to schools could help reduce disparities in drinking water excellence across schools.
Article
Introduction: Water is the most abundant constituent of the human body. An adequate hydration prevents various diseases and it is important for the maintenance of a good health. Objectives: We aimed to evaluate the hydration status and the contribution of meals as well as food and beverages groups to the total water intake in a sample of children, aged 7 to 11 years. Methodology: A sample of 199 (97 boys and 102 girls), 7-11 years-old children were included in this study. We evaluated the hydration status from the collection of a 24-hour urine sample and quantified the urinary markers for the calculation of the Free Water Reserve. A 24 h food recall was applied for the period of collection of the urine sample, for further analysis on food contribution to total daily water intake. The contribution of water of each meal was also evaluated. The values of the Free Water Reserve calculation allowed the sample classification in euhydrated children in which Free Water Reserve positive values indicate euhydration and the negative values to hypohydration. The Free Water Reserve and the percentage contribution of food groups and beverages as well as meals were compared by sex, using the Mann Whitney test. Results: Most of the children were classified as being euhydrated (86.4%). The food group that contributed to water intake in boys and in girls was dairy products (23.8% and 25.7% respectively). In terms of meals, lunch is the main source of water intake (38.7%). Girls have healthier choices by choosing water (17%) and fruit (8.8%) rather than soft drinks (6.4%). Conclusions: Most children was euhydrated. Nevertheless it is important to encourage the consumption of foods with higher water content and a more balanced distribution throughout the day.
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Water is an essential nutrient for life and the most abundant component in the human body. However, its dietary recommendations or clinical management guidelines do not receive as much attention as they deserve. In addition, there are some obstacles to establishing optimal values, both for the amount of water the body must contain and for water ingestion. Water intake and elimination depend on unsteady factors that are difficult to measure and, at the same time, compensated by the body's ability to regulate homeostasis. Since scientific evidence is lacking for establishing recommendations, “adequate intakes” (to maintain an adequate hydration state) have been estimated using data on water intake from groups of healthy people. The European Food Safety Authority (EFSA) also considers desirable the use of urine osmolarity to estimate the adequacy of water intake in adults. Clinical studies have generally shown the benefits of adequate hydration and the damage caused by water imbalance, whether quantitative (dehydration and overhydration) or qualitative (extracellular and intracellular water). Unfortunately, these studies are few and often have poor cross-sectional, case-control, or prospective designs, and use small samples or indirect methods to assess hydration status. This article presents up-to-date information on subjects such as: 1) compliance with water consumption recommendations and suggestions for improvement; 2) techniques available to measure hydration status and their clinical applications; 3) effects of hydration/dehydration on physical or cognitive activities and chronic diseases; and 4) existing Spanish regulations on the quality and salubrity of water. KEY WORDS: water intake, hydration, dehydration, health status, extracellular water, intracellular water
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This study was performed to determine whether a) children voluntarily dehydrate while exercising in hot climate; b) such dehydration affects their well-being and thermoregulation. Eleven 10p to 12-yr old, partially acclimatized boys underwent two work-in-the-heat protocols (cycle rides, 45% aerobic capacity at 39 degrees C, 45% rh). During one session they drank only voluntarily when thirsty (VD). In the other, drinking was forced (FD) to replenish fluid losses. VD induced a progressively increasing fluid loss (0.3% of body wt.h-1) due to insufficient drinking (72% of intake in FD). URinary output was lower (55.7 vs. 81.6 ml.h-1) and its osmolality higher (880 vs. 523 meq.1-1) than during FD. Sweat rate, rectal (Tre) and mean skin (T-sk) temperatures, heart rate, rate of perceived exertion, sweat gland counts, blood hemoglobin, hematocrit (Hct), serum electrolytes, and total proteins did not differ between sessions. However, the rise of Tre, Hct, and proteins positively correlated with hypohydration level. It is concluded that exercising children progressively dehydrate when not forced to drink. At equal levels of % weight loss they have greater Tre rise than do lean adults.
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Whether mental performance is affected by slowly progressive moderate dehydration induced by water deprivation has not been examined previously. Therefore, objective and subjective cognitive-motor function was examined in 16 volunteers (8 females, 8 males, mean age: 26 yr) twice, once after 24 h of water deprivation and once during normal water intake (randomized cross-over design; 7-day interval). Water deprivation resulted in a 2.6% decrease in body weight. Neither cognitive-motor function estimated by a paced auditory serial addition task, an adaptive 5-choice reaction time test, a manual tracking test, and a Stroop word-color conflict test nor neurophysiological function assessed by auditory event-related potentials P300 (oddball paradigm) differed (P > 0.1) between the water deprivation and the control study. However, subjective ratings of mental performance changed significantly toward increased tiredness (+1.0 points) and reduced alertness (-0.9 points on a 5-point scale; both: P < 0.05), and higher levels of perceived effort (+27 mm) and concentration (+28 mm on a 100-mm scale; both: P < 0.05) necessary for test accomplishment during dehydration. Several reaction time-based responses revealed significant interactions between gender and dehydration, with prolonged reaction time in women but shortened in men after water deprivation (Stroop word-color conflict test, reaction time in women: +26 ms, in men: -36 ms, P < 0.01; paced auditory serial addition task, reaction time in women +58 ms, in men -31 ms, P = 0.05). In conclusion, cognitive-motor function is preserved during water deprivation in young humans up to a moderate dehydration level of 2.6% of body weight. Sexual dimorphism for reaction time-based performance is present. Increased subjective task-related effort suggests that healthy volunteers exhibit cognitive compensating mechanisms for increased tiredness and reduced alertness during slowly progressive moderate dehydration.
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(1) To describe the occurrence of voluntary dehydration in two classes of elementary school students as expressed by their morning and noon-time urine osmolality; and (2) to determine the relationship between the children's scores on cognitive tests and their state of hydration. Group comparison among fifty-eight sixth-grade students (age range 10.1-12.4 y old) during mid-June at two schools in a desert town. Morning and noon-time urine samples were collected in school, and five cognitive tests were scored in the morning and at noon-time. Main outcome measures: (1) morning and noon-time urine osmolality; (2) scores of five cognitive tests (hidden figures, auditory number span, making groups, verbal analogies, and number addition) that were applied in the morning and at noon-time. Thirty-two students were dehydrated (urine osmolality above 800 mosm/kg H(2)O) in the morning. An individual's noon-time urine osmolality was highly related to morning osmolality (r=0.67, p=0.000). The morning cognitive scores were similar in the hydrated and dehydrated students (p=0.443). The adjusted mean scores of the noon-time tests, with the morning test scores as covariates, demonstrated an overall positive trend in four of the five tests in favor of the hydrated group (p=0.025). The effect was mainly due to the auditory number span test (p=0.024). Voluntary dehydration is a common phenomenon in school-aged children that adversely affects cognitive functions.
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To describe associations between hydration status and dietary behaviour in children, as current research indicates that hydration status is influenced by nutrition vice versa, hydration status may influence dietary behaviour. Cross-sectional analyses of data from the Dortmund Nutritional and Anthropometric Longitudinally Designed Study, (DONALD) using 24-h urine samples to determine the hydration status and 3-day weighed food records to describe the dietary profile of the children. Secondary analyses of data from an observational study. A group of 4-11 year old children living in Dortmund, Germany; N=717. Hydration status was determined by calculating the 'free water reserve', using analyses of the 24-h urine samples. Nutrient intake per day was calculated from the 3-day weighed food records. Children were categorized into groups of hydration status and analysed for significant differences in their dietary profile. Children in the highest group of the hydration status had significant higher total water intake, lower energy density of the diet and a lower proportion of metabolic water compared to children in the lowest group of the hydration status. In addition, analyses showed - although not significant in all subgroups - that better hydrated children consumed more water from beverages and water-supplying foods and less energy from fat. Euhydrated children, that are children in the highest group of hydration status, had a more preferable dietary profile than children at risk of insufficient hydration. Funding for the DONALD Study and its analyses is provided by the Ministry of Innovation, Science, Research and Technology of the State of North Rhine-Westphalia, Germany.
Article
We investigated the beneficial effects of drinking supplementary water during the school day on the cognitive performance and transitory subjective states, such as fatigue or vigor, in 168 children aged between 9 and 11years who were living in a hot climate (South Italy, Sardinia). The classes were randomly divided into an intervention group, which received water supplementation, and a control group. Dehydration was determined by urine sampling and was defined as urine osmolality greater than 800mOsm/kg H(2)O (Katz, Massry, Agomn, & Toor, 1965). The change in the scores from the morning to the afternoon of hydration levels, cognitive performance and transitory subjective states were correlated. In line with a previous observational study that evaluated the hydration status of school children living in a country with a hot climate (Bar-David, Urkin, & Kozminsky, 2005), our results showed that a remarkable proportion of children were in a state of mild, voluntary dehydration at the beginning of the school day (84%). We found a significant negative correlation between dehydration and the auditory number span, which indicates a beneficial effect of drinking supplementary water at school on short-term memory. Moreover, there was a positive correlation between dehydration and performance in the verbal analogy task. The results are discussed in the light of the complexity of the neurobiological mechanisms involved in the relationship between hydration status and cognition.
Article
Variation in mental performance under different levels of heat stress-induced dehydration was recorded in 11 subjects heat acclimatized to the tropicals. Dehydration was induced by a combination of water restriction and exercise in heat. The psychological functions--arithmetic ability, short-term memory, and visuomotor tracking--were assessed in a thermoneutral room after the subjects recovered fully from the effects of exercise in heat, as reflected by their oral temperature and heart rate. The results indicated significant deterioration in mental functions at 2% or more body dehydration levels.
Article
The effect of primary dehydration of various levels (1, 2 and 3% body-weight deficits) on mental functions of different complexities were studied in eight heat-acclimatized subjects drawn from tropical regions of India. These subjects were also studied after a bout of exercise in heat under two conditions viz., Hot Dry (45°C DB, 30% rh), and Hot Humid (39DC DB, 60% rh) at 34°C WBGT. No significant change in routine mental work was seen either under dehydration per se of any level or after subsequent exercise under heat when compared with the normal state. On the other hand, at 2 and 3% levels of primary dehydration a further reduction was noted in all the functions though it was not significant. Inter-variations in Hot Humid and Hot Dry conditions were not significant except for more pronounced reductions in the concentration component in Hot Humid conditions.
Article
This study investigated the effects of heat exposure, exercise-induced dehydration and fluid ingestion on cognitive performance. Seven healthy men, unacclimatized to heat, were kept euhydrated or were dehydrated by controlled passive exposure to heat (H, two sessions) or by treadmill exercise (E, two sessions) up to a weight loss of 2.8%. On completion of a 1-h recovery period, the subjects drank a solution containing 50 g l(-1) glucose and 1.34 g l(-1) NaCl in a volume of water corresponding to 100% of his body weight loss induced by dehydration. (H1 and E1) or levels of fluid deficit were maintained (H0, E0). In the E0, H0 and control conditions, the subject drank a solution containing the same quantity of glucose diluted in 100 ml of water. Psychological tests were administered 30 min after the dehydration phase and 2 h after fluid ingestion. Both dehydration conditions impaired cognitive abilities (i.e. perceptive discrimination, short-term memory), as well as subjective estimates of fatigue, without any relevant differences between the methods. By 3.5 h after fluid deficit, dehydration (H0 and E0) no longer had any adverse effect, although the subjects felt increasingly tired. Thus, there was no beneficial effect of fluid ingestion (H1 and E1) on the cognitive variables. However, long-term memory retrieval was impaired in both control and dehydration situations, whereas there was no decrement in performance in the fluid ingestion condition (H1, E1).
Article
Despite the seemingly ubiquitous admonition to "drink at least eight 8-oz glasses of water a day" (with an accompanying reminder that beverages containing caffeine and alcohol do not count), rigorous proof for this counsel appears to be lacking. This review sought to find the origin of this advice (called "8 x 8" for short) and to examine the scientific evidence, if any, that might support it. The search included not only electronic modes but also a cursory examination of the older literature that is not covered in electronic databases and, most importantly and fruitfully, extensive consultation with several nutritionists who specialize in the field of thirst and drinking fluids. No scientific studies were found in support of 8 x 8. Rather, surveys of food and fluid intake on thousands of adults of both genders, analyses of which have been published in peer-reviewed journals, strongly suggest that such large amounts are not needed because the surveyed persons were presumably healthy and certainly not overtly ill. This conclusion is supported by published studies showing that caffeinated drinks (and, to a lesser extent, mild alcoholic beverages like beer in moderation) may indeed be counted toward the daily total, as well as by the large body of published experiments that attest to the precision and effectiveness of the osmoregulatory system for maintaining water balance. It is to be emphasized that the conclusion is limited to healthy adults in a temperate climate leading a largely sedentary existence, precisely the population and conditions that the "at least" in 8 x 8 refers to. Equally to be emphasized, lest the message of this review be misconstrued, is the fact (based on published evidence) that large intakes of fluid, equal to and greater than 8 x 8, are advisable for the treatment or prevention of some diseases and certainly are called for under special circumstances, such as vigorous work and exercise, especially in hot climates. Since it is difficult or impossible to prove a negative-in this instance, the absence of scientific literature supporting the 8 x 8 recommendation-the author invites communications from readers who are aware of pertinent publications.
Article
This highly summarized attempt to theorize about the psychology of schizophrenia is derived from studies carried out over a number of years at 3 institutions—the Worcester State Hospital, the University of Illinois, and, most recently, the National Institute of Mental Health.* Much of the material on which my discussion will be based is as yet unpublished, although many studies are in print and some phases of the theory have been discussed before. The data will, however, be organized and viewed somewhat differently from the way in which I have dealt with them in the past. Numerous colleagues at these institutions—many of whose names will arise * '"" the course of the presentation—have been involved in these studies. The generalizations I shall draw from them on this occasion are, however, my sole responsibility. These data raise several basic questions on the order of the following: What characterizes the formal schizophrenic
Article
Little is known about the relation of hydration status to cognitive performance in older adults, who may be more vulnerable to poor hydration and cognitive impairment. We examined whether hydration status was related to cognitive functioning in 28 healthy community-dwelling older adults. Hierarchical regression models demonstrated that lower hydration status was related to slowed psychomotor processing speed and poorer attention/memory performance, after controlling for demographic variables and blood pressure.
Article
Adequate fluid intake is critical for survival. While adults are at liberty to drink fluids as wanted, children and infants are dependent upon caregivers for food and fluid. Children are at greater risk for dehydration than adults due to their higher surface-to-mass ratio. Additionally, children have different thirst sensitivities and body cooling mechanisms than adults. Children differ from adults in total body water content, and boys and girls differ in body water content with maturation. Research in young adults shows that mild dehydration corresponding to only 1% to 2% of body weight loss can lead to significant impairment in cognitive function. Dehydration in infants is associated with confusion, irritability, and lethargy; in children, it may produce decrements in cognitive performance.
Article
Water is essential for health. The 'Water is Cool in School' campaign promoted improved drinking water access in UK schools. Implementation has been patchy, and impact has not been studied. The aim of this study is to determine whether fluid intake and frequency of toilet visits are associated with children's access to drinking water in the classroom. A total of 145 schoolchildren in Year 2 (aged 6-7 years) and 153 in Year 5 (aged 9-10 years) classes were studied in six Southampton schools. Total fluid intake and toilet visits were recorded during one school day. Schools were recruited according to drinking policy: 'prohibited access' = water prohibited in classroom; 'limited access' = water allowed in classroom but not on the desk; and 'free access' = water bottle encouraged on the desk. Data were analysed on an intention-to-treat basis. In total, 120 children in prohibited access, 91 in limited access and 87 in free access settings were recruited. Total fluid intake was significantly higher in Year 2 free access schools (geometric mean 293, range 104-953 mL) compared with prohibited access schools (geometric mean 189, range 0-735 mL, P=0.046), in Year 5 free access schools (geometric mean 489, range 88-1200 mL) compared with prohibited access schools (geometric mean 206, range 0-953 mL, P=0.001), and in free access versus limited access schools (geometric mean 219, range 0-812 mL, P=0.003). A total of 81% and 80% of children in prohibited and limited access schools, respectively, consumed below the minimum recommended amount of total fluid at school, compared with 46.5% in the free access schools. In total, 34.6% of children did not use the toilets at all during the school day. There was no trend observed between water access and frequency of toilet visits (median of 1 trip for each group, P=0.605). Most children have an inadequate fluid intake in school. Free access to drinking water in class is associated with improved total fluid intake. Primary schools should promote water drinking in class.
Article
The impact of breakfasts of different glycaemic loads on the performance of nineteen children, aged six to seven years, was explored. Over a four week period, children attended a school breakfast club each day and ate one of three meals. Each meal offered a similar amount of energy but differed in their glycaemic load. When working individually, the behaviour of a child was rated in the classroom every ten seconds for 30 min to produce a measure of time spent on task. Memory was assessed by asking for the recall of a series of objects. The ability to sustain attention was measured by asking for a response after various delays. The incidence of negative behaviour was recorded when playing a video game that was too difficult to allow success. Two to three hours after a low glycaemic load breakfast had been consumed, performance on the tests of memory and the ability to sustain attention were better, fewer signs of frustration were displayed and initially more time was spent on task when working individually in class. The importance of the results was discussed in the context of the wide range of factors that influence behaviour in school.
Article
The performance of both physical and mental tasks can be adversely affected by heat and by dehydration. There are well-recognized effects of heat and hydration status on the cardiovascular and thermoregulatory systems that can account for the decreased performance and increased sensation of effort that are experienced in the heat. Provision of fluids of appropriate composition in appropriate amounts can prevent dehydration and can greatly reduce the adverse effects of heat stress. There is growing evidence that the effects of high ambient temperature and dehydration on exercise performance may be mediated by effects on the central nervous system. This seems to involve serotonergic and dopaminergic functions. Recent evidence suggests that the integrity of the blood brain barrier may be compromised by combined heat stress and dehydration, and this may play a role in limiting performance in the heat.
Article
The limited literature on the effects of dehydration on human cognitive function is contradictory and inconsistent. Although it has been suggested that decrements in cognitive performance are present in the range of a 2 to 3% reduction in body weight, several dose-response studies indicate dehydration levels of 1% may adversely affect cognitive performance. When a 2% or more reduction in body weight is induced by heat and exercise exposure, decrements in visual-motor tracking, short-term memory and attention are reported, but not all studies find behavioral effects in this range. Future research should be conducted using dose-response designs and state-of-the-art behavioral methods to determine the lowest levels of dehydration that produce substantive effects on cognitive performance and mood. Confounding factors, such as caffeine intake and the methods used to produce dehydration, need to be considered in the design and conduct of such studies. Inclusion of a positive control condition, such as alcohol intake, a hypnotic drug, or other treatments known to produce adverse changes in cognitive performance should be included in such studies. To the extent possible, efforts to blind both volunteers and investigators should be an important consideration in study design.
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