The purpose of this Special Issue, “Water Intake, Body Water Regulation, and Health”, is to present novel reviews and experimental data regarding hydration physiology and its implication in overall health. Water has previously been dubbed the forgotten nutrient due to humans’ and animals’ ability to subsist seemingly unchanged across a wide range of daily water intakes. However, with the introduction of stressors such as exercise, diseased states, and/or chronic high or low water intake, the homeostatic signals related to body water regulation can influence organ and whole-body health. This Special Issue will discuss water intake, the scientific rationale surrounding the U.S. and European water intake guidelines, homeostatic mechanisms, diseases related to dysfunction of water regulation, and differences in the volume and the vehicle in which the water is contained (i.e., plain water versus mixed beverages) on water intake during and following exercise. The aim is to continue discussion surrounding water, the previously forgotten nutrient, and highlight the importance of water in daily life.

Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate The Dietary Reference Intakes (DRIs) are quantitative estimates of nutrient intakes to be used for planning and assessing diets for healthy people. This new report, the sixth in a series of reports presenting dietary reference values for the intakes of nutrients by Americans and Canadians, establishes nutrient recommendations on water, potassium, and salt for health maintenance and the reduction of chronic disease risk. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate discusses in detail the role of water, potassium, salt, chloride, and sulfate in human physiology and health. The major findings in this book include the establishment of Adequate Intakes for total water (drinking water, beverages, and food), potassium, sodium, and chloride and the establishment of Tolerable Upper Intake levels for sodium and chloride. The book makes research recommendations for information needed to advance the understanding of human requirements for water and electrolytes, as well as adverse effects associated with the intake of excessive amounts of water, sodium, chloride, potassium, and sulfate. This book will be an invaluable reference for nutritionists, nutrition researchers, and food manufacturers.

Athletes and nonathletes frequently consume too little water or fluids, affecting exercise performance as well as overall health. This book comprehensively reviews the aspects relating to body fluid balance, rehydration, and physical exercise. It provides background on body water balance and turnover, topics related to electrolyte balance, and sweating as the basis for thermoregulatory and fluid homeostasis during exercise. In addition, chapters cover body water balance evaluation and regulation; cardiovascular and metabolic responses to fluid imbalance; effects of dehydration on aerobic power, muscle strength, and cognitive function; fluid intake timing; and optimal beverage selection.

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The quality of drinking water is paramount for public health. Despite important improvements in the last decades, access to safe drinking water is not universal. The World Health Organization estimates that almost 10% of the population in the world do not have access to improved drinking water sources. Among other diseases, waterborne infections cause diarrhea, which kills nearly one million people every year, mostly children under 5 years of age. On the other hand, chemical pollution is a concern in high-income countries and an increasing problem in low- and middle-income countries. Exposure to chemicals in drinking water may lead to a range of chronic non-communicable diseases (e.g., cancer, cardiovascular disease), adverse reproductive outcomes, and effects on children’s health (e.g., neurodevelopment), among other health effects. Although drinking water quality is regulated and monitored in many countries, increasing knowledge leads to the need for reviewing standards and guidelines on a nearly permanent basis, both for regulated and newly identified contaminants. Drinking water standards are mostly based on animal toxicity data, and more robust epidemiologic studies with accurate exposure assessment are needed. The current risk assessment paradigm dealing mostly with one-by-one chemicals dismisses the potential synergisms or interactions from exposures to mixtures of contaminants, particularly at the low-exposure range. Thus, evidence is needed on exposure and health effects of mixtures of contaminants in drinking water. Finally, water stress and water quality problems are expected to increase in the coming years due to climate change and increasing water demand by population growth, and new evidence is needed to design appropriate adaptation policies. This Special Issue of International Journal of Environmental Research and Public Health (IJERPH) focuses on the current state of knowledge on the links between drinking water quality and human health.

A timely symposium entitled Body-Fluid Homeostasis: Transduction and Integration was held at Araraquara, São Paulo, Brazil in 2011. This meeting was convened as an official satellite of a joint gathering of the International Society for Autonomic Neuroscience (ISAN) and the American Autonomic Society (AAS) held in Buzios, Rio de Janeiro. Broad international participation at this event generated stimulating discussion among the invited speakers, leading to the publication of Neurobiology of Body Fluid Homeostasis: Transduction and Integration. Drawn from the proceedings and filled with rich examples of integrative neurobiology and regulatory physiology, this volume: Provides updated research using human and animal models for the control of bodily fluids, thirst, and salt appetite Explores neural and endocrine control of body fluid balance, arterial pressure, thermoregulation, and ingestive behavior Discusses recent developments in molecular genetics, cell biology, and behavioral plasticity Reviews key aspects of brain serotonin and steroid and peptide control of fluid consumption and arterial pressure The book highlights research conducted by leading scientists on signal transduction and sensory afferent mechanisms, molecular genetics, perinatal and adult long-term influences on regulation, central neural integrative circuitry, and autonomic/neuroendocrine effector systems. The findings discussed by the learned contributors are relevant for a basic understanding of disorders such as heat injury, hypertension, and excess salt intake. A unique reference on the neurobiology of body fluid homeostasis, this volume is certain to fuel additional research and stimulate further debate on the topic.

This book reviews the research pertaining to nutrient requirements for working in cold or in high-altitude environments and states recommendations regarding the application of this information to military operational rations. It addresses whether, aside from increased energy demands, cold or high-altitude environments elicit an increased demand or requirement for specific nutrients, and whether performance in cold or high-altitude environments can be enhanced by the provision of increased amounts of specific nutrients.