Hydration Levels Can Affect Cardiovascular Health

Minor dehydration might promote cardiac disease and arterial hardening as much as smoking in young, healthy men, according to a new study.

Researchers at Harokopio University (Kallithea, Greece), Alexandra University Hospital (Athens, Greece), and the University of Arkansas (Fayetteville, USA) conducted a crossover study in 10 young, healthy males (median age 24.3, median weight 80.8 kg, median BMI 24.3 kg/m²) to investigate if acute hypohydration affects endothelial and cardiovascular function. Each subject completed two measurements of endothelial function by flow-mediated dilation (FMD) in euhydrated and hypohydrated states, separated by 24 hours.

Following baseline assessment, the participants completed 100 minutes of low-intensity intermittent walking exercise to achieve hypohydration of −2% of individual body mass; for the rest of the day, a standardized, low water content diet was provided. The following morning, hydration markers and endothelial function were recorded. The results showed decreased plasma volume (3.5 ± 1.8%), and increased plasma osmolality (mean 9 mmol/kg), accompanied by a 27% mean decrease in FMD. The study was published in the March 2016 issue of the European Journal of Nutrition.

“You could be mildly dehydrated without knowing it while you have endothelial impairment similar to smoking a cigarette,” said corresponding author Stavros Kavouras, PhD, coordinator of the exercise science program at the University of Arkansas. “The degree of dehydration when these changes occur is at less than two percent dehydration, which is around the threshold when people start feeling thirsty.”

Vascular endothelium is an active paracrine, endocrine, and autocrine organ that is indispensable for regulation of vascular tone and maintenance of vascular homeostasis. Endothelial dysfunction due to CVD risk factors promotes both the early and late mechanisms of atherosclerosis, including up-regulation of adhesion molecules, increased chemokine secretion and leukocyte adherence, increased cell permeability, enhanced low-density lipoprotein oxidation, platelet activation, cytokine elaboration, and vascular smooth muscle cell proliferation and migration.

Related Links:
Harokopio University
Alexandra University Hospital
University of Arkansas