The Role of Hydration in Children and Adolescents-A Theoretical Framework for Reviewing Recommendations, Models, and Empirical Studies.

Proper hydration is essential for maintaining homeostasis and the effective functioning of physiological systems, including the nervous and circulatory systems. During adolescence, a period characterized by rapid somatic growth, hormonal maturation, and increased physical and mental activity, the demand for water increases significantly. Hydration affects not only the health of young people, but also their cognitive abilities, concentration, mood, and general well-being. Despite clear recommendations from institutions such as EFSA and IOM regarding daily fluid intake, numerous studies indicate that a significant proportion of young people do not achieve the recommended level of hydration. The school environment is particularly worrying, as young people spend a significant part of their day there, and the availability of water, health knowledge, and social conditions may contribute to dehydration or promote unhealthy choices (e.g., sweetened drinks). The aim of this article is to review the current state of knowledge on the importance of hydration in school-age adolescents. The physiological basis of hydration, the impact of insufficient fluid intake on the functioning of the young body, current guidelines, as well as the results of selected epidemiological studies and obstacles to ensuring optimal hydration in the school environment are discussed.