posthydration

Posthydration is the phase after a period of dehydration during which fluids and electrolytes are replenished to restore normal body water content and plasma volume. It may follow exercise in heat, illness causing vomiting or diarrhea, or inadequate fluid intake.

Physiology: Rehydration involves replacing water and electrolytes, particularly sodium, to restore osmolality and blood volume. Gastric emptying and intestinal absorption influence the rate at which fluids are taken up, and carbohydrates can enhance water and electrolyte absorption.

Methods: Oral rehydration therapy using fluids with electrolytes and carbohydrates; sports drinks or plain water in milder cases; intravenous fluids for severe dehydration or when oral intake is not possible. The choice depends on severity, age, and clinical context.

Guidelines and considerations: After dehydration, aim to replace body-mass losses with fluids for several hours, with electrolyte-containing beverages preferred to reduce the risk of hyponatremia. Monitor intake and signs of overhydration, such as swelling or rapid weight gain.

Contexts: Posthydration is relevant in sports, medicine, and occupational health, with pediatric and geriatric considerations. In diarrhea or vomiting, oral rehydration solutions are standard and endorsed by health authorities.