Dietary Salt Intake Exaggerates Arterial Blood Pressure during Exercise in healthy Normotensive Adults

Abstract

High dietary salt intake is associated with an increased risk for the development of hypertension, cardiovascular (CVD) and cerebrovascular disease. Additionally, exaggerated blood pressure during dynamic exercise is independently predictive of future CVD beyond resting blood pressure and other conventional risk factors. This is critical given that in animal models, dietary salt negatively augments blood pressure responses during static hind‐limb contractions, suggesting an increased risk of an adverse CVD event during exercise with high dietary salt. However, it currently remains unknown if high salt intake increases arterial blood pressure and impairs vascular function during voluntary dynamic exercise in healthy men and women. Based on previous preclinical reports, we hypothesized that high salt intake would decrease resting vascular endothelial function, increase arterial blood pressure during dynamic exercise and decrease functional sympatholysis. Thirteen healthy men and women underwent a randomized, double‐blind, placebo‐controlled trial for 7 days with either 15g/day sodium chloride supplement or cellulose. Beat‐by‐beat mean (MAP), systolic (SBP) and diastolic (DBP) were recorded throughout the trial on the non‐exercising limb. Forearm blood flow (FBF) was calculated via mean blood velocity derived from ultrasonography on the brachial artery of the exercising limb. All patients performed a flow‐mediated dilation (FMD) protocol followed by (20% maximal voluntary contraction) submaximal hand‐grip exercise for 7 min with lower‐body negative pressure initiated during min 5 – 7. FMD was significantly reduced during the HS condition (HS: 2.2±0.26e−5; Pl: 4.1±0.56e−5; p<0.01). Compared to placebo, the absolute steady‐state exercise MAP and SBP were significantly higher during HS compared to the placebo condition (p<0.05). However, functional sympatholysis was not different between conditions (p=0.07). In summary, the results of this study show the effects of HS intake on arterial blood pressure during handgrip exercise. These findings highlight that the augmented exercise blood pressures may be key mediator for the increased risk for adverse CVD outcomes associated with high dietary salt intake.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.