What is the role of sodium (Na) and water in rehydration?

From the Guidelines

Rehydration with Sodium and Water

Rehydration with salt and water is crucial as it replenishes essential electrolytes, particularly sodium, which helps regulate fluid balance and maintain proper bodily functions 1. The World Health Organization-recommended oral rehydration solution (ORS) typically contains 75mmol/L of sodium and 75mmol/L of glucose, which can be administered in a dose of 50-100ml/kg body weight over 3-4 hours 1.

Key Components of Rehydration

• Sodium: essential for regulating fluid balance and maintaining proper bodily functions 1
• Water: necessary for replenishing lost fluids and maintaining hydration 1
• Glucose: helps facilitate the absorption of sodium and water in the intestine 1

Administration of ORS

The administration of ORS should be tailored to the individual's needs, taking into account the degree of dehydration, age, and weight 1. For example:

• Infants and children: 50-100 mL/kg of ORS over 3-4 hours 1
• Adolescents and adults: 2-4 L of ORS over 3-4 hours 1

Importance of Rehydration

Rehydration is essential for managing diarrhea and preventing complications such as dehydration, electrolyte imbalances, and organ failure 1. It is also important to note that breastfed infants should continue nursing throughout the illness, and maintenance fluids should be resumed along with an age-appropriate normal diet after rehydration is complete 1.

From the Research

Role of Sodium and Water in Rehydration

• Sodium (Na) plays a crucial role in rehydration, particularly in the absorption of water in the intestines 2, 3.
• The use of oral rehydration solutions (ORS) that contain sodium and glucose is recommended for rehydration in diarrheal illness and during vigorous exercise 2, 3.
• The optimal concentration of sodium in ORS is still a topic of debate, with some studies suggesting that reduced-osmolarity solutions with lower sodium content may be more effective in reducing stool output and duration of diarrhea 4, 5, 6.
• Water is also essential for rehydration, and the consumption of adequate amounts of water is necessary to replace lost fluids and electrolytes 2, 3.
• The combination of sodium and water in ORS helps to regulate the balance of fluids and electrolytes in the body, which is critical for maintaining proper hydration and preventing complications such as hyponatremia or hypernatremia 2, 3, 4.

Oral Rehydration Solutions

• ORS typically contain a combination of sodium, glucose, and water, which helps to promote the absorption of water and electrolytes in the intestines 2, 3, 5, 6.
• The World Health Organization (WHO) recommends the use of reduced-osmolarity ORS, which contains slightly less sodium and glucose than previously recommended formulations 4, 6.
• The use of ORS has been shown to be effective in reducing the duration and severity of diarrhea, as well as the need for intravenous fluid treatment 4, 5, 6.

Exercise-Induced Dehydration

• During vigorous exercise, individuals require adequate amounts of sodium and water to maintain proper hydration and prevent dehydration 2.
• The consumption of sodium-containing snacks and fluids before, during, and after exercise can help to regulate the balance of fluids and electrolytes in the body 2.
• The use of sports drinks that contain sodium and other electrolytes may be beneficial for individuals who engage in high-intensity exercise or experience excessive sweating 2.