Vascular Responses to Sympathetic Activation and Altered Shear Rate: The Impact of Hypertension and Sodium Intake

The aim of this study is to determine if alterations in sodium intake alter peripheral vascular function and exercise tolerance in young individuals.

Study Overview

• Status: Completed
• Conditions: Hypertension
• Intervention / Treatment: Dietary supplement: Salt Pills; Dietary supplement: Placebo Pills

Detailed Description

Sodium intake is a major contributor to the development of hypertension in the developed world. Interestingly, it has been recently revealed that, in addition to the cardiovascular dysfunction associated with high sodium intake-induced hypertension, individuals who have unaltered blood pressure after chronic high sodium intake, termed salt resistant, report similar reductions in cardiovascular function when compared to salt sensitive individuals. While the extent to which this high sodium intake negatively alters cardiovascular structure as well as function is currently being explored, little is known about how high sodium intake impacts vascular function and blood flow regulation during exercise. Therefore, this study will determine if alterations in sodium intake alter peripheral vascular function and exercise tolerance in young individuals. The investigators hypothesize that increases in sodium intake will reduce exercise-induced arterial dilation in response to shear and result in exercise intolerance, via impaired functional sympatholysis, at moderate-to-high exercise workloads. Furthermore, the investigators hypothesize that these changes in blood flow regulation and exercise tolerance in young individuals will be reversed following antioxidant supplementation, implicating the role of oxidative stress in this dysfunction.

• Study Type: Interventional
• Enrollment (Actual): 34
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Virginia
    • Richmond, Virginia, United States, 23298
      • Virginia Commonwealth University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• normotensive blood pressure (Systolic <120 AND Diastolic <80
• free of cardiovascular disease and any evidence of thyroid, renal, metabolic, pulmonary or neurological disease
• non-obese (BMI <30 and/or Body fat < 25% for men, and < 30% for women)
• no tobacco use
• no medications that could affect vascular function or oxidative stress
• not sedentary

Exclusion Criteria:

• individual with cardiovascular, pulmonary, or metabolic disease or taking medications that may alter cardiovascular, pulmonary, or metabolic function
• subjects will be asked to maintain a dietary record for one week subsequent to the pre-screening and if this reveals a diet that differs substantially from the "typical" average diet, the subject will not be eligible
• subjects will be excluded from the study if dietary records reveal significant caloric restriction and/or vitamin/mineral deficiencies
• pregnant women, prisoners, and children will not be eligible for this study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Salt Pills; One week on low salt diet plus salt pills	Dietary supplement: Salt Pills; 7 days of a low sodium diet plus 4 salt pills (sodium chloride) taken 3 times daily with meals (approximately 7000 milligrams per day)
Placebo Comparator: Placebo Pills; One week on low salt diet plus placebo pills	Dietary supplement: Placebo Pills; 7 days of low sodium diet plus 4 placebo pills (microcrystalline cellulose) taken 3 times daily with meals

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Arterial Dilation in Response to Exercise	Percent change is arterial diameter when compared to baseline	After 7 day high salt supplementation vs After 7 day low salt supplementation

Collaborators and Investigators

• Sponsor: Virginia Commonwealth University
• Investigators: Principal Investigator: Ryan Garten, PhD, Virginia Commonwealth University

Study record dates

Study Major Dates

• Study Start (Actual): May 15, 2018
• Primary Completion (Actual): November 5, 2021
• Study Completion (Actual): November 5, 2021

Study Registration Dates

• First Submitted: June 4, 2018
• First Submitted That Met QC Criteria: June 4, 2018
• First Posted (Actual): June 15, 2018

Study Record Updates

• Last Update Posted (Estimate): January 13, 2023
• Last Update Submitted That Met QC Criteria: January 12, 2023
• Last Verified: January 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension
• Other Study ID Numbers: HM20013060

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No