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Nutrients Jun 2019Endurance events have experienced a significant increase in growth in the new millennium and are popular activities for participation globally. Sports nutrition... (Review)
Review
BACKGROUND
Endurance events have experienced a significant increase in growth in the new millennium and are popular activities for participation globally. Sports nutrition recommendations for endurance exercise however remains a complex issue with often opposing views and advice by various health care professionals.
METHODS
A PubMed/Medline search on the topics of endurance, athletes, nutrition, and performance was undertaken and a review performed summarizing the current evidence concerning macronutrients, hydration, and supplements as it pertains to endurance athletes.
RESULTS
Carbohydrate and hydration recommendations have not drastically changed in years, while protein and fat intake have been traditionally underemphasized in endurance athletes. Several supplements are commercially available to athletes, of which, few may be of benefit for endurance activities, including nitrates, antioxidants, caffeine, and probiotics, and are reviewed here. The topic of "train low," training in a low carbohydrate state is also discussed, and the post-exercise nutritional "recovery window" remains an important point to emphasize to endurance competitors.
CONCLUSIONS
This review summarizes the key recommendations for macronutrients, hydration, and supplements for endurance athletes, and helps clinicians treating endurance athletes clear up misconceptions in sports nutrition research when counseling the endurance athlete.
Topics: Athletes; Diet; Dietary Supplements; Drinking; Feeding Behavior; Humans; Nutrients; Nutrition Policy; Nutritional Requirements; Physical Conditioning, Human; Physical Endurance; Sports; Sports Nutritional Physiological Phenomena; Sports Nutritional Sciences; Water
PubMed: 31181616
DOI: 10.3390/nu11061289 -
Nutrients Jul 2019Personalized hydration strategies play a key role in optimizing the performance and safety of athletes during sporting activities. Clinicians should be aware of the many... (Review)
Review
Personalized hydration strategies play a key role in optimizing the performance and safety of athletes during sporting activities. Clinicians should be aware of the many physiological, behavioral, logistical and psychological issues that determine both the athlete's fluid needs during sport and his/her opportunity to address them; these are often specific to the environment, the event and the individual athlete. In this paper we address the major considerations for assessing hydration status in athletes and practical solutions to overcome obstacles of a given sport. Based on these solutions, practitioners can better advise athletes to develop practices that optimize hydration for their sports.
Topics: Athletes; Dehydration; Drinking; Humans; Sports; Water
PubMed: 31324008
DOI: 10.3390/nu11071550 -
Nutrients Mar 2020The biological feedback provided by human water intake upon our physiology is grossly under-investigated [...].
The biological feedback provided by human water intake upon our physiology is grossly under-investigated [...].
Topics: Body Composition; Body Water; Body Weight Maintenance; Drinking; Female; Health; Humans; Male; Nutritional Physiological Phenomena
PubMed: 32155865
DOI: 10.3390/nu12030702 -
Best Practice & Research. Clinical... Sep 2020In primary polydipsia pathologically high levels of water intake physiologically lower arginine vasopressin (AVP) secretion, and in this way mirror the secondary... (Review)
Review
In primary polydipsia pathologically high levels of water intake physiologically lower arginine vasopressin (AVP) secretion, and in this way mirror the secondary polydipsia in diabetes insipidus in which pathologically low levels of AVP (or renal responsiveness to AVP) physiologically increase water intake. Primary polydipsia covers several disorders whose clinical features and significance, risk factors, pathophysiology and treatment are reviewed here. While groupings may appear somewhat arbitrary, they are associated with distinct alterations in physiologic parameters of water balance. The polydipsia is typically unrelated to homeostatic regulation of water intake, but instead reflects non-homeostatic influences. Recent technological advances, summarized here, have disentangled functional neurocircuits underlying both homeostatic and non-homeostatic physiologic influences, which provides an opportunity to better define the mechanisms of the disorders. We summarize this recent literature, highlighting hypothalamic circuitry that appears most clearly positioned to contribute to primary polydipsia. The life-threatening water imbalance in psychotic disorders is caused by an anterior hippocampal induced stress-diathesis that can be reproduced in animal models, and involves phylogenetically preserved pathways that appear likely to include one or more of these circuits. Ongoing translational neuroscience studies in these animal models may potentially localize reversible pathological changes which contribute to both the water imbalance and psychotic disorder.
Topics: Animals; Diabetes Insipidus; Drinking; Homeostasis; Humans; Hyponatremia; Polydipsia; Polydipsia, Psychogenic; Risk Factors; Water-Electrolyte Balance; Water-Electrolyte Imbalance
PubMed: 33222764
DOI: 10.1016/j.beem.2020.101469 -
Nutricion Hospitalaria Oct 2020Water 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...
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.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; Cross-Sectional Studies; Diet; Disease; Drinking; Female; Guidelines as Topic; Health; Humans; Infant; Infant, Newborn; Male; Middle Aged; Nutrition Surveys; Prospective Studies; Spain; Water; Water Quality; Young Adult
PubMed: 32960634
DOI: 10.20960/nh.03160 -
Science (New York, N.Y.) Nov 2022Water is essential for survival, but one in three individuals worldwide (2.2 billion people) lacks access to safe drinking water. Water intake requirements largely...
Water is essential for survival, but one in three individuals worldwide (2.2 billion people) lacks access to safe drinking water. Water intake requirements largely reflect water turnover (WT), the water used by the body each day. We investigated the determinants of human WT in 5604 people from the ages of 8 days to 96 years from 23 countries using isotope-tracking (H) methods. Age, body size, and composition were significantly associated with WT, as were physical activity, athletic status, pregnancy, socioeconomic status, and environmental characteristics (latitude, altitude, air temperature, and humidity). People who lived in countries with a low human development index (HDI) had higher WT than people in high-HDI countries. On the basis of this extensive dataset, we provide equations to predict human WT in relation to anthropometric, economic, and environmental factors.
Topics: Female; Humans; Pregnancy; Exercise; Humidity; Life Style; Social Class; Water; Infant, Newborn; Infant; Child, Preschool; Child; Adolescent; Young Adult; Adult; Middle Aged; Aged; Aged, 80 and over; Drinking
PubMed: 36423296
DOI: 10.1126/science.abm8668 -
Nutrients Apr 2020Increased hydration is recommended as healthy habit with several merits. However, supportive data are sparse. To assess the efficacy of increased daily water intake, we... (Randomized Controlled Trial)
Randomized Controlled Trial
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.
Topics: Aged; Asian People; Biomarkers; Blood Pressure; Blood Urea Nitrogen; Body Temperature; Body Water; Drinking; Female; Gastrointestinal Microbiome; Glomerular Filtration Rate; Healthy Volunteers; Humans; Kidney; Male; Middle Aged; Nutritional Physiological Phenomena; Organism Hydration Status
PubMed: 32340375
DOI: 10.3390/nu12041191 -
Nutrients Sep 2021Low-intake dehydration is a common and often chronic condition in older adults. Adverse health outcomes associated with low-intake dehydration in older adults include... (Review)
Review
Low-intake dehydration is a common and often chronic condition in older adults. Adverse health outcomes associated with low-intake dehydration in older adults include poorer cognitive performance, reduced quality of life, worsened course of illness and recovery, and a high number of unplanned hospital admissions and increased mortality. The subjective methods to assess (risk of) dehydration are not reliable, and the evidence about preventive measures are also limited. So is the knowledge about the optimal intake of beverages per day. This narrative review presents the state of the science on the role of low intake hydration in older adults. Despite its simple cause-the inadequate intake of beverages-low-intake dehydration appears to be a very complex problem to address and much more research is needed in the area. Based on the existing evidence, it seems necessary to take setting specific differences and individual problems and needs into account to tackle dehydration in older adults. Further, it is necessary to increase awareness of the prevalence and severity of low-intake dehydration among older adults and in nursing staff in care homes and hospitals as well as among caregivers of older adults living at home.
Topics: Age Factors; Aged; Dehydration; Drinking; Humans
PubMed: 34579019
DOI: 10.3390/nu13093142 -
Nutrients Mar 2020Reducing consumption of free sugars, such as those found in high concentrations in manufactured products such as sugar-sweetened beverages (SSBs) and 100% fruit juices,...
Reducing consumption of free sugars, such as those found in high concentrations in manufactured products such as sugar-sweetened beverages (SSBs) and 100% fruit juices, is a global public health priority. This study aimed to measure prevalence of widely available pre-packaged non-alcoholic water-based beverages (carbonated sodas, sports drinks, energy drinks, artificially-sweetened sodas, fruit juices (any type), and bottled water) and to comprehensively examine behavioral, environmental, current health, and demographic correlates of consumption. A cross-sectional, nationally-representative population survey of 3430 Australian adults (18+ years) was conducted using computer-assisted telephone (mobile and landline) interviewing. Past week prevalence of pre-packaged drinks containing free sugar was 47.3%; daily prevalence was 13.6%. Of all the pre-packaged drinks assessed, consumption of fruit juices (any type) was the most prevalent (38.8%), followed by bottled water (37.4%), soda (28.9%), artificially-sweetened soda (18.1%), sports drinks (8.1%), and energy drinks (4.2%). Higher soda consumption was associated with males, younger age, socio-economic disadvantage, frequent takeaway food consumption, availability of soda in the home, obesity, and a diagnosis of heart disease or depression. A diagnosis of Type 2 Diabetes was associated with increased likelihood of consuming artificially-sweetened sodas and decreased likelihood of consuming sugar-sweetened soda. SSB consumption is prevalent in Australia, especially among young adults and males, foreshadowing continued population weight gain and high burdens of chronic disease. To reduce consumption, Australia must take a comprehensive approach, incorporating policy reform, effective community education, and active promotion of water.
Topics: Adolescent; Adult; Aged; Australia; Drinking; Drinking Behavior; Drinking Water; Female; Fruit and Vegetable Juices; Health Surveys; Humans; Male; Middle Aged; Sugar-Sweetened Beverages; Sweetening Agents; Young Adult
PubMed: 32204487
DOI: 10.3390/nu12030817 -
Journal of the International Society of... Oct 2020Despite a substantial body of research, no clear best practice guidelines exist for the assessment of hydration in athletes. Body water is stored in and shifted between... (Review)
Review
BACKGROUND
Despite a substantial body of research, no clear best practice guidelines exist for the assessment of hydration in athletes. Body water is stored in and shifted between different sites throughout the body complicating hydration assessment. This review seeks to highlight the unique strengths and limitations of various hydration assessment methods described in the literature as well as providing best practice guidelines.
MAIN BODY
There is a plethora of methods that range in validity and reliability, including complicated and invasive methods (i.e. neutron activation analysis and stable isotope dilution), to moderately invasive blood, urine and salivary variables, progressing to non-invasive metrics such as tear osmolality, body mass, bioimpedance analysis, and sensation of thirst. Any single assessment of hydration status is problematic. Instead, the recommended approach is to use a combination, which have complementary strengths, which increase accuracy and validity. If methods such as salivary variables, urine colour, vital signs and sensation of thirst are utilised in isolation, great care must be taken due to their lack of sensitivity, reliability and/or accuracy. Detailed assessments such as neutron activation and stable isotope dilution analysis are highly accurate but expensive, with significant time delays due to data analysis providing little potential for immediate action. While alternative variables such as hormonal and electrolyte concentration, bioimpedance and tear osmolality require further research to determine their validity and reliability before inclusion into any test battery.
CONCLUSION
To improve best practice additional comprehensive research is required to further the scientific understanding of evaluating hydration status.
Topics: Absorptiometry, Photon; Blood Physiological Phenomena; Body Mass Index; Body Water; Dehydration; Drinking; Electric Impedance; Hematocrit; Hormones; Humans; Neutron Activation Analysis; Osmolar Concentration; Saliva; Serum; Sodium; Sports; Tears; Thirst; Urinalysis; Vital Signs
PubMed: 33126891
DOI: 10.1186/s12970-020-00381-6