Cardiopulmonary Testing in ME/CFS to Improve Diagnostic Accuracy


Circumstantial evidence suggests that patients diagnosed with myalgic encephalopathy/chronic fatigue syndrome (ME/CFS) perform worse on day 2 in a 2-day consecutive cardiopulmonary exercise test (CPET). The aim of this study is to examine if CPET can distinguish between ME/CFS patients and healthy controls.

Full Title of Study: “Cardiopulmonary Exercise Testing as a Diagnostic Tool and a Quantitative Measure of Post-exertional Malaise in Myalgic Encephalopathy/Chronic Fatigue Syndrome”

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Prospective
  • Study Primary Completion Date: April 2019

Detailed Description

Myalgic encephalopathy/chronic fatigue syndrome (ME/CFS) leads to a substantial reduction in activity level. Cardiopulmonary exercise testing (CPET) quantifies physical performance, or functional capacity, by direct measurements of the maximal oxygen uptake (VO2max). Functional capacity is the ability of an individual to perform aerobic work as defined by the VO2max, and the assessment of functional capacity reflects the ability to perform activities of daily living that require sustained aerobic metabolism.

To the best of knowledge few robustly designed studies on repeated CPET in ME/CFS are published, and they demonstrated a significant reduction in functional capacity expressed as VO2max and anaerobic threshold. This marked functional decline on the second test has apparently not been described for any other chronic, disabling conditions, and might represent a possible diagnostic tool for ME/CFS; hence the investigators will examine this. In addition they will examine other biological markers (e.g. cytokines and anti-oxidative compounds) before and after the exercise tests to test if the groups can be further distinguished.

The main aim of this study is to evaluate the use of repeated CPET as an objective diagnostic marker of ME/CFS. Specifically the investigators want to address the following questions:

I. Will patients with ME/CFS demonstrate a significant reduction in VO2max compared to healthy individuals? If such a difference can be demonstrated, is it unique for patients with ME/CFS classified according to the strictest criteria compared to others with longstanding fatigue?

II. What is the blood lactate profile before, during and after CPET?

III. Are there any correlations between the decline in VO2max and other biological variables such as markers of oxidative stress, immune dysregulation or metabolic dysfunction?

IV. Is cardiac function impaired among ME/CFS patients as assessed by ecco-cardiography?

Three groups will be included: (i) ME/CFS patients; (ii) patients with fatigue, but not MF/CFS; and (iii) healthy controls.


  • Procedure: Cardiopulmonary testing
    • A 2-day consecutive testing on an ergometer cycle

Arms, Groups and Cohorts

  • ME/CFS group
    • Patients with a verified diagnosis of ME/CFS according to the Canada criteria
  • Fatigue group
    • Patients with fatigue, but not ME/CFS
  • Control group
    • Healthy control persons

Clinical Trial Outcome Measures

Primary Measures

  • Maximal oxygen uptake
    • Time Frame: At 48 hour
    • Measurement of oxygen uptake during ergometer cycling

Secondary Measures

  • Lactate accumulation
    • Time Frame: At 48 hour
    • Regular sampling of blood for measurements of lactate
  • Cytokine profile
    • Time Frame: At 48 hour
    • Regular sampling of blood for measurements of cytokines
  • Immunophenotyping
    • Time Frame: At 48 hour
    • Regular sampling of blood for measurements of cell surface markers
  • Cardiac status
    • Time Frame: At 48 hour
    • Measurements of Cardiac function using ecco-cardiography

Participating in This Clinical Trial

Inclusion Criteria

  • Diagnosed with ME/CFS according to the Canadian and Fukuda criteria; miid to moderately affected)
  • Provide written consent
  • Able to perform the test

Exclusion Criteria

  • Not provided written consent
  • Unable to perform the test

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • University of Oslo
  • Collaborator
    • The Glittre Clinic
  • Provider of Information About this Clinical Study
    • Principal Investigator: Per Ole Iversen, MD, Professor – University of Oslo
  • Overall Official(s)
    • Per O Iversen, MD, Principal Investigator, University of Oslo

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