Intravenous (IV) Saline and Exercise in Postural Tachycardia Syndrome (POTS)


The investigators will test whether an intravenous infusion of saline (salt water) will improve the exercise capacity in patients with postural tachycardia syndrome (POTS).

Full Title of Study: “Intravenous Saline on Exercise Tolerance in Orthostatic Intolerance”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Non-Randomized
    • Intervention Model: Crossover Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: June 2021


  • Drug: Saline
    • IV Normal Saline infused over 30-60 minutes given 3-6 hours PRIOR to exercise study
  • Other: Placebo
    • Placebo x1 lactose tablet

Arms, Groups and Cohorts

  • Experimental: Exercise Post Saline
    • Saline infusion 1L hours before exercise test
  • Placebo Comparator: Placebo
    • Placebo given prior to exercise test

Clinical Trial Outcome Measures

Primary Measures

  • Difference in VO2max between saline day and placebo day
    • Time Frame: Within 2 week
    • VO2max will be measured hours after saline and after placebo. The 2 interventions will be less than 2 weeks apart.

Secondary Measures

  • Exercise capacity/Maximal Load (Watts) during peak VO2
    • Time Frame: Less than 2 weeks
    • Maximal exercise load will be measured hours after saline and after placebo. The 2 interventions will be less than 2 weeks apart.
  • Cardiac output between exercise tests (inert gas rebreathing technique)
    • Time Frame: 2-10 Days between exercise tests

Participating in This Clinical Trial

Inclusion Criteria

  • Meet diagnostic criteria of Postural Tachycardia Syndrome (POTS) 28
  • Age between 18-65 years
  • Male and female are eligible (although the majority of POTS patients are female).
  • Able and willing to provide informed consent

Exclusion Criteria

  • Presence of medical conditions that can explain postural tachycardia (e.g., acute dehydration, medications)
  • Pregnancy
  • Other factors which in the investigator's opinion would prevent the subject from completing the protocol.
  • Patients who are bedridden or chair-ridden

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 65 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Vanderbilt University
  • Provider of Information About this Clinical Study
    • Principal Investigator: Satish R. Raj, Adjunct Associate Professor of Medicine – Vanderbilt University Medical Center
  • Overall Official(s)
    • Satish R Raj, MD MSCI, Principal Investigator, Vanderbilt University


Raj SR, Biaggioni I, Yamhure PC, Black BK, Paranjape SY, Byrne DW, Robertson D. Renin-aldosterone paradox and perturbed blood volume regulation underlying postural tachycardia syndrome. Circulation. 2005 Apr 5;111(13):1574-82. Epub 2005 Mar 21.

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