Two-day cardiopulmonary exercise test

Two-day cardiopulmonary exercise testing or 2-day CPET is an accepted, reliable test for post-exertional malaise (PEM), one of the cardinal symptoms that distinguishes between individuals with and without ME/CFS. The hypothesis is that ME/CFS patients are almost unique in having a severe deterioration in the second of the two cardiopulmonary exercise tests performed on consecutive days.

The CPET is the same non-invasive test given to measure the fitness levels of athletics, as well as, people with cardiopulmonary illness. However, if the test is repeated 24 hours later, ME/CFS patients will fare significantly worst than they did on the first day. The Institute of Medicine report states that: "ME/CFS patients have significantly lower results on CPET 2 than on CPET 1 on one or more of the following parameters: VO2max (Keller et al., 2014; VanNess et al., 2007; Vermeulen et al., 2010), VO2 at ventilatory threshold (Keller et al., 2014), and maximal workload or workload at ventilatory threshold (Keller et al., 2014; Snell et al., 2013)."

Although the Institute of Medicine report states that 2-day CPET is very reliable to objectively measure PEM, the IOM committee emphasized "that the CPET is not required to diagnose patients with ME/CFS. Further, this test carries substantial risk for these patients as it may worsen their condition (Nijs et al., 2010; VanNess et al., 2010)."

Evidence

 * 2014, Inability of myalgic encephalomyelitis/chronic fatigue syndrome patients to reproduce VO₂peak indicates functional impairment (Betsy Keller)
 * 2013, Discriminative validity of metabolic and workload measurements for identifying people with chronic fatigue syndrome (Christopher Snell, Staci Stevens, Davenport TE, Mark VanNess)

Harm
The 2015 Institute of Medicine report stated:

"...the CPET is not required to diagnose patients with ME/CFS. Further, this test carries substantial risk for these patients as it may worsen their condition."

Cost & availability

 * Workwell Foundation (United States, CA)
 * Betsy Keller at Ithaca College (United States, NY) Cost is $2200. Because they are based in a college setting (not healthcare setting), they cannot process insurance (including Medicare or Medicaid), so the patient would need to work directly with their insurer about reimbursement. (private email)
 * Charles Lapp and Laura Black, both at Hunter-Hopkins, Charlotte, NC
 * Open Medicine Institute Clinic

Talks & interviews

 * 2014, Mark VanNess 'Exercise and ME/CFS' at Bristol Watershed. Part One
 * 2013, CPET Presentation by Dr. Christopher Snell, Part ICPET Presentation by Dr. Christopher Snell, Part II

Learn more

 * The Workwell Foundation: Testing for Disability
 * 2013, Busted! Exercise Study Finds Energy Production System is Broken in Chronic Fatigue Syndrome
 * 2013, Repeat Test Reveals Dramatic Drop in ME/CFS Exercise Capacity
 * 2007, Legal and Scientific Considerations of the Exercise Stress Test