Clinical Question: What is the evidence that drinking plenty of fluids is effective and not harmful in patients with respiratory tract infection?

Setting: Various (meta-analysis)

Study Design: Systematic review

Synopsis: The authors of this study attempted to determine whether drinking extra fluids while experiencing a respiratory tract infection is evidence based or a medical myth. With appropriate rigor, they searched several databases, examined references of relevant papers, and contacted experts in an attempt to find studies on the subject. As might be expected, there were no randomized controlled trials. They found two studies reporting hyponatremia at rates of 31 percent and 45 percent in children with moderate to severe pneumonia but without signs of dehydration, and several case series in which children developed hyponatremia during a respiratory infection that responded to fluid restriction.

Bottom Line: There is no research evaluating whether drinking plenty of fluids is beneficial to patients with respiratory tract infections. Although the benefit seems to be self-evident, there is a theoretic risk of harm. Antidiuretic hormone secretion increases in adults and children with lower respiratory tract infections who drink large amounts of fluids, and hyponatremia has been documented in cohort and case studies. Evidence to support either continuing the practice or stopping the practice is weak. (Level of Evidence: 1c)