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Related Concept Videos

Regulation of Water Intake01:25

Regulation of Water Intake

Osmolality refers to the number of solute particles per kilogram of solvent in a solution. Plasma osmolality specifically indicates the total number of solute particles per kilogram of water in blood plasma. This value reflects the body's hydration status and is tightly regulated through mechanisms controlling water intake and output. While water consumption is a conscious decision, the body has intrinsic regulatory systems to maintain fluid balance. Dehydration, a state of water deficit...
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The hydration of cement is an exothermic reaction in which heat is generated as cement hydrates. This heat of hydration is critical to cement's strength development. The rate at which this heat is generated affects the temperature rise, with a majority of the heat being released early in the hydration process, half within the first three days, and about 75% within the first week.
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Body Water Content and Fluid Compartments

Life's biochemical processes occur within aqueous solutions. Solutes are substances that are dissolved within these solutions. The human body contains a variety of solutes, which can differ across various body parts. These can encompass proteins—such as those responsible for clotting and carbohydrate transport—as well as electrolytes. In medicine, an electrolyte is often described as a mineral ion derived from a salt possessing an electric charge. Examples include sodium ions (Na+) and chloride...
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Evaluation of Hydration Status by Bioelectrical Impedance Vector Analysis in Patients with Ischemic Heart Disease Undergoing Exercise Stress Test
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Human hydration indices: acute and longitudinal reference values.

Lawrence E Armstrong1, Amy C Pumerantz, Kelly A Fiala

  • 1Human Performance Laboratory, University of Connecticut, Storrs, CT, USA.

International Journal of Sport Nutrition and Exercise Metabolism
|May 19, 2010
PubMed
Summary
This summary is machine-generated.

This study establishes reference values for euhydration in healthy, active men, finding that morning urine is more concentrated than 24-hour samples. These hydration metrics are crucial for understanding fluid balance in daily life.

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Area of Science:

  • Human physiology
  • Sports science
  • Nutrition science

Background:

  • Accurate documentation of fluid intake and excretion in free-living individuals is challenging.
  • Human water balance regulation is complex and dynamic, making hydration status difficult to assess.
  • Lack of established reference values for euhydration hinders the interpretation of hydration extremes.

Purpose of the Study:

  • To provide reference values for euhydration using body mass, daily fluid intake, and serum osmolality.
  • To compare urinary indices between initial morning samples and 24-hour collections.
  • To establish hydration extremes for commonly used indices in healthy, active men.

Main Methods:

  • 59 healthy, active men participated in a 12-day study with five observation periods.
  • Participants meticulously recorded daily food and fluid intake, as well as exercise.
  • Collected and analyzed initial morning urine samples and 24-hour urine collections for various hydration indices.

Main Results:

  • Mean total fluid intake exceeded 2.1 L/24 hr, with mean urine volume over 1.3 L/24 hr.
  • Mean urine specific gravity was >1.018 and mean urine color was >=4; rarely did participants achieve values below 1.010 or color of 1.
  • Morning urine samples were more concentrated than 24-hour collections, and urine specific gravity strongly correlated with osmolality (r2 = .81–.91, p < .001).

Conclusions:

  • Established reference values for euhydration and hydration extremes for seven common indices in healthy, active men.
  • Demonstrated that initial morning urine samples provide a more concentrated view of hydration status compared to 24-hour collections.
  • Confirmed the strong correlation between urine specific gravity and osmolality as reliable indicators of hydration.