title: Water ingestion reduces skin blood flow through sympathetic vasoconstriction.
abstract: OBJECTIVE
  Water ingestion induces a pressor effect in patients with efferent baroreflex impairment and a mild pressor effect in elderly healthy subjects. However, water raised the total peripheral vascular resistance (TPR) without a prominent change in blood pressure in young healthy subjects. We try to investigate whether water elicits a cardiovascular response via regulating regional skin blood flow (SkBF) in young healthy subjects.
  
  
  METHODS
  In a randomized, controlled, crossover fashion, 15 healthy male subjects (19-27 years old) ingested either 500 (water session) or 50 ml of water (control). The heart rate, blood pressure, cardiac index, and TPR were measured using a Task Force Monitor. A laser Doppler velocimeter was used to determine the change in the SkBF at the left thenar eminence. Plasma catecholamines and their metabolites were also measured.
  
  
  RESULTS
  At 25 min after ingestion of 500 ml water, the cardiac index and SkBF significantly decreased compared to control. In contrast, the TPR significantly increased after ingestion of 500 ml water. Plasma dihydroxyphenylalanine significantly increased at 25 min after water.
  
  
  CONCLUSIONS
  Water ingestion decreases the cardiac index to compensate for the increase in the TPR, leading to no net change in blood pressure in young healthy subjects. This study suggests that water decreases the SkBF, a mechanism that might account partly for the nature of osmopressor response to water in young healthy subjects.
authors: Department of Anesthesiology, Tri-Service General Hospital/National Defense Medical Center, and Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors: Chih-Cherng
authors: CC
authors: Lu
authors: Min-Hui
authors: MH
authors: Li
authors: Tso-Chou
authors: TC
authors: Lin
authors: Ta-Liang
authors: TL
authors: Chen
authors: Ruei-Ming
authors: RM
authors: Chen
authors: Che-Se
authors: CS
authors: Tung
authors: Ching-Jiunn
authors: CJ
authors: Tseng
authors: Shung-Tai
authors: ST
authors: Ho
mesh_terms: D000328:Adult; D001810:Blood Volume / Q000502:physiology*; D018592:Cross-Over Studies; D004326:Drinking / Q000502:physiology*; D006801:Humans; D008297:Male; D012039:Regional Blood Flow / Q000502:physiology*; D012867:Skin / Q000098:blood supply* / Q000294:innervation; D013564:Sympathetic Nervous System / Q000502:physiology*; D014661:Vasoconstriction / Q000502:physiology*; D055815:Young Adult