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The Effects of Dietary Salt on Post-exercise Hypotension

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ClinicalTrials.gov Identifier: NCT03565653
Recruitment Status : Recruiting
First Posted : June 21, 2018
Last Update Posted : June 25, 2018
Sponsor:
Information provided by (Responsible Party):
William Farquhar, University of Delaware

Brief Summary:
The new American Heart Association (AHA) blood pressure guidelines are expected to raise the prevalence of high blood pressure to ~46% in the United States. One recommendation for lowering blood pressure is aerobic exercise, which produces a period of lowered blood pressure (post-exercise hypotension; PEH) that lasts up to 24 hours. It is believed that PEH may be responsible for the observations of lowered blood pressure following initiation of exercise. However, most Americans eat too much salt, which expands plasma volume and may prevent PEH, rending aerobic exercise ineffective in improving blood pressure status.

Condition or disease Intervention/treatment Phase
Blood Pressure Post-Exercise Hypotension Other: High dietary salt Other: Placebo Not Applicable

Detailed Description:
Recently released blood pressure guidelines from the American Heart Association and American College of Cardiology are expected to raise the prevalence of hypertension in America from ~33% to ~46%. A single bout of aerobic exercise produces a prolonged period (up to 24 hours) of lowered blood pressure (post-exercise hypotension; PEH). Repeated bouts of aerobic exercise results in maintenance of lowered blood pressure, leading to recommendations of aerobic exercise for improvement of blood pressure status. However, more than 90% of Americans consume more sodium in their diets than is recommended. This is alarming, as excess dietary sodium intake expands plasma fluid volume, which may in turn attenuate the reduction in BP following exercise. Therefore, the objective of this project is to determine the effects of high dietary sodium intake on PEH. The investigators hypothesize that, compared to a recommended sodium diet, a high salt diet will attenuate post-exercise hypotension.

Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 20 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Basic Science
Official Title: The Effects of Dietary Salt on Post-exercise Hypotension
Actual Study Start Date : May 1, 2018
Estimated Primary Completion Date : May 1, 2019
Estimated Study Completion Date : May 1, 2019

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Experimental: High dietary salt
For 10 days each, participants will be asked to eat a recommended sodium diets (2300 mg Na+/d) while taking unmarked pills containing uniodized table salt. On the 10th day, participants will report to the lab to complete 60 minutes of cycling exercise. Following exercise, participants will rest for 60 minutes while undergoing serial blood pressure measurements. Participants will then be outfitted with ambulatory blood pressure cuffs for assessment of blood pressure over the following 24 hours.
Other: High dietary salt
~4,000 mg Na+/day

Experimental: Placebo
For 10 days each, participants will be asked to eat a recommended sodium diets (2300 mg Na+/d) while taking unmarked pills containing a placebo (dextrose). Participants will complete both interventions in random order. On the 10th day, participants will report to the lab to complete 60 minutes of cycling exercise. Following exercise, participants will rest for 60 minutes while undergoing serial blood pressure measurements. Participants will then be outfitted with ambulatory blood pressure cuffs for assessment of blood pressure over the following 24 hours.
Other: Placebo
dextrose




Primary Outcome Measures :
  1. Post-exercise hypotension [ Time Frame: 24 hours following exercise ]
    Change in mean arterial pressure from pre- to post-exercise


Secondary Outcome Measures :
  1. Blood pressure reactivity [ Time Frame: 10th day of high salt diet ]
    Change in mean, systolic, and diastolic blood pressure from baseline to exercise



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Ages Eligible for Study:   18 Years to 40 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Recreationally active

Exclusion Criteria:

  • high blood pressure (>140/90 mmHg)
  • history of cardiovascular disease
  • history of cancer
  • history of diabetes
  • history of kidney disease
  • obesity (BMI > 30 kg/m2)
  • smoking or tobacco use
  • current pregnancy
  • nursing mothers
  • communication barriers

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03565653


Contacts
Contact: William B Farquhar, PhD 302-831-6178 wbf@udel.edu

Locations
United States, Delaware
Department of Kinesiology and Applied Physiology, University of Delaware Recruiting
Newark, Delaware, United States, 19713
Contact: William B Farquhar, PhD    302-831-6178    wbf@udel.edu   
Principal Investigator: Matthew C Babcock, MS         
Principal Investigator: William B Farquhar, PhD         
Sponsors and Collaborators
University of Delaware

Responsible Party: William Farquhar, Professor, University of Delaware
ClinicalTrials.gov Identifier: NCT03565653     History of Changes
Other Study ID Numbers: 1085139
First Posted: June 21, 2018    Key Record Dates
Last Update Posted: June 25, 2018
Last Verified: June 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided

Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No

Additional relevant MeSH terms:
Hypotension
Post-Exercise Hypotension
Vascular Diseases
Cardiovascular Diseases
Orthostatic Intolerance
Primary Dysautonomias
Autonomic Nervous System Diseases
Nervous System Diseases