WATER INTAKE EFFECT ON AUTONOMIC NERVOUS SYSTEM: A SYSTEMATIC REVIEW AND META-ANALYSIS

ABSTRACT

To verify, through a systematic review, the effect of water intake (WI) on the autonomic nervous system (ANS) and hemodynamic variables in adults. Studies published between 2000 and 2015 were analyzed, with reference to Medline database via Pubmed, and also MeSH was used in the construction of the search phrase. The following inclusion criteria were established: randomized and controlled clinical trials (RCTs) performed in humans, in English. Exclusion criteria: unclear, poorly described or inadequate interventions and in the form of abstracts. The following variables were used for selecting studies: heart rate (HR), blood pressure (BP), high frequency component (HF) and peripheral vascular resistance (PVR). The PRISMA systematization was used for the elaboration of this review and a meta-analysis was conducted in order to mathematically evidence the results of heart rate after water intake in seven studies that evaluated this variable. Ten RCTs were part of this review, involving 246 subjects aged 19-64 years, of whom 34.55% were male. Most RCTs analyzed showed changes after WI. Changes commonly observed were the following: decreased HR (statistically significant p < 0.001), increased HF and PVR. However, in relation to BP results proved to be conflicting with studies that showed increase and others that showed no significant difference. This review shows the effect of WI on ANS, particularly in HR, HF and PVR, despite that, in relation to hemodynamic changes expressed by BP, an obstacle still remains regarding the scientific community.

Keywords:
drinking; autonomic nervous system; arterial pressure; heart rate; vascular resistance