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.

Theory
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.

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)

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)

Talks & interviews

 * 2014, Mark VanNess 'Exercise and ME/CFS' at Bristol Watershed. Part One

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