What is the average percentage of total body water for a full-term infant?

The average percentage of total body water for a full-term infant is around 70%. This is significantly higher than the percentage of body water in adults, which typically ranges from about 50% to 60%. Infants have a higher water content because their bodies are still developing, and water is crucial for various physiological processes that support growth and development.

The higher percentage of total body water in infants is primarily due to their larger proportion of extracellular fluid compared to adults. Extra fluid is necessary for metabolic activities and helps in maintaining homeostasis as infants grow and their organ systems mature. This elevated water content also puts infants at a greater risk of dehydration, as they can lose a larger proportion of their body water quickly due to factors such as illness or environmental conditions.

Understanding this aspect of infant physiology is essential for healthcare providers, particularly in pediatric care, where fluid management is critical. Awareness of the normal water composition helps guide treatment decisions regarding hydration and electrolyte balance in this vulnerable population.