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Learning Outcomes

By the end of this section, you should be able to:

  • 2.4.1 Describe the nutritional function of hydration.
  • 2.4.2 Identify the impact of hydration on wellness promotion and illness prevention.
  • 2.4.3 Examine special considerations for individuals who face challenges securing adequate hydration.

Hydration Function

Water is the universal solvent; every cell, tissue, and organ requires water to transport essential substances. Molecules dissolve into the watery blood environment and move through the body, providing cellular support. Blood also carries breakdown products for elimination. Staying hydrated is essential to good health and can be accomplished by responding to thirst and intentionally monitoring fluid intake. See Figure 2.3 for the use of urine concentration as an indicator of hydration status.

This color chart shows different shades of yellow and associates each shade with hydration or dehydration. The lighter shades represent hydration while the darker shades represent dehydration.
Figure 2.3 A color chart indicates the hydration level of urine. A very pale color indicates overhydration, whereas darker colors indicate underhydration. (credit: modification of work from Anatomy and Physiology 2e. attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license)

Water has zero calories and is readily available. Plain water is best; tea, coffee, and sodas also provide fluids but often contain caffeine and sugar. How much water or other fluids are needed daily depends on body size, disease state, and activity level. According to the Academy of Nutrition and Dietetics, the recommended amount of water consumed per day is about 11.5 cups for women and 15.5 cups for men. This includes fluids consumed from both foods and beverages. Approximately 20% of this water comes from food consumption, which brings the fluid recommendations to about 9 cups per day for women and 13 cups per day for men (Gordon & Klemm, 2022).

Special Considerations

Hydration and Older Adults

Older adults are at risk for dehydration because of diminished thirst and may cut back their fluid intake to avoid trips to the bathroom. Encouraging fluids can help mitigate poor fluid intake.

Both food and fluids help an individual stay hydrated, enabling all body functions to perform optimally. Commercially bottled water is convenient, but given the problem with plastic waste, as well as the lack of fluoride in most bottled water, the use of refillable water bottles is an eco-friendly and bone-healthy alternative. The Centers for Disease Control and Prevention (2020) reports that that bottled water may lack a sufficient amount of fluoride, which is important for oral health and preventing tooth decay.

Other highly advertised beverages include hydration drinks containing electrolytes, sugar, and caffeine. These drinks, sometimes referred to as sports drinks, may be helpful after intense exercise in adults but are not typically needed for children unless they are experiencing nausea and vomiting and require electrolyte replacement (Munoz-Urtuba et al., 2023). The more vigorous and longer the duration of the exercise, the more support research has provided for rehydration beverages containing both carbohydrates and electrolytes (McDermott et al., 2017).

Two simple ways the nurse can check for hydration status include tenting of the skin and the color of urine. The darker the urine, the greater the need for fluid (Figure 2.3).

Water Safety

Drinking water piped into homes may come from municipal water supplies or originate from a private well. Whereas municipal water supplies are monitored by the U.S. Environmental Protection Agency, well water is considered “private water,” and the safety is in the hands of the well owner (U.S. Environmental Protection Agency, 2023). Safe drinking water does not receive much attention until a public health emergency occurs. Natural disasters such as hurricanes, floods, and tornadoes can introduce microorganisms or chemicals to municipal water supplies, making it unsafe. The county or state health departments issue notifications for unsafe water. Usually, boiling water can kill microorganisms (Centers for Disease Control and Prevention, 2021); however, a water filter is needed to remove chemicals and heavy metals (Centers for Disease Control and Prevention, 2022).

Healthy Water

Healthy water is usually taken for granted until sanitation or safety concerns make it a public health issue. The Centers for Disease Control and Prevention (2022) provide education on a vast array of healthy water topics.


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