CPET – Cardiopulmonary Exercise Test

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Frequently Asked Questions

About Workwell

Workwell has been utilizing cardiopulmonary exercise testing (CPET) with clinical populations for more than 25 years. They follow guidelines established by the American College of Sports Medicine and have been trained to provide special care for patients with fatigue-related conditions. Workwell has expertise researching and evaluating disability impairment for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), fibromyalgia syndrome (FMS), Lyme disease, and other pain/fatiguing conditions.

Workwell has been invited to present and/or serve in advisory capacities to numerous organizations including the U.S. Department of Health and Human Services, the Food and Drug Administration, the National Institutes of Health, the Centers for Disease Control and Prevention, and the Institute of Medicine (now National Academy of Medicine). Workwell has an extensive list of publications that are cited frequently in the professional literature and other media.

Workwell was the first group to research and publish a 2-day cardiopulmonary exercise test (CPET) procedure in people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Their protocol consists of two CPETs separated by 24 hours. During each test the patient is required to pedal on a stationary bicycle at a comfortable speed while workload gradually increases over time until maximal effort criteria is achieved.

Workwell tests individuals with a variety of fatigue-related chronic illnesses that hinder the ability to function or work. If an individual has fatigue that affects quality of life or ability to work, cardiopulmonary exercise testing (CPET) can be a valuable tool to document impairment.

Workwell does not diagnose. They are a group of exercise physiologists and physical therapists with expertise in cardiopulmonary exercise testing (CPET) and fatigue-related illnesses. The written report can be used by a medical provider for diagnostic purposes.

About Cardiopulmonary Exercise Testing (CPET)

Cardiopulmonary exercise testing (CPET) is considered the most accurate non-invasive tool for assessing maximal aerobic capacity and determining submaximal sustained exercise performance. The American Heart Association and European Association for Cardiovascular Prevention and Rehabilitation describe CPET as the “gold standard aerobic exercise tolerance assessment.” CPET provides valuable information to identify the origins of aerobic impairment and unexplained shortness of breath in people experiencing multiple chronic comorbidities.

A typical test consists of pedaling on a stationary bicycle for 8-12 minutes (sometimes less) while expired gases (exhaled breaths) are sampled to determine oxygen consumption, carbon dioxide production, and pulmonary ventilation. Heart rate, blood pressure, and arterial oxygen saturation are assessed throughout the test using a 12-lead electrocardiogram (ECG), blood pressure cuff, and pulse oximeter.

CPET is endorsed for clinical purposes by many professional medical organizations including:

2-Day CPET is also recognized by the National Academy of Medicine (NAM, formally Institute of Medicine) as an objective measure of post-exertional malaise (PEM) and recovery after physical exertion.  The California Chapter of the American College of Cardiology recommends 2-day CPET to identify biomarkers consistent with CFS/PEM.

Workwell developed the 2-day test-retest CPET protocol to assess post-exertional malaise and ability to work on consecutive days. In many cases, a single test may not be sufficient to document an abnormal test. The National Academy of Medicine states that 2-day CPET can objectively measure post-exertional malaise or a decline in functional capacity after physical exertion. If an individual lacks the ability to work or recover from daily activities, a test-retest protocol can be used to document functional impairment and/or fatigue.

A lighter ramping protocol is used for severely ill patients, but criteria for maximal effort must be achieved for the test to be valid. Workwell uses a stationary bicycle ergometer instead of a treadmill for safety reasons and offers the option of medical supervision for high-risk patients.

Workwell prepares a comprehensive report interpreting CPET results for individuals with complex fatiguing conditions. This report can be used for disability purposes due to its objective nature and ability to document fatigue and post-exertional malaise. Writing the report requires expertise and knowledge that combines health, exercise science, and the legal aspects of disability evaluation.

The final report typically takes 2-3 weeks but can sometimes be expedited.

CPET is an objective tool that accurately measures the point at which a person achieves the ventilatory/anaerobic threshold (V/AT) and corresponding heart rate. Patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and similar fatiguing conditions are instructed to minimize the amount of time spent above their V/AT. To do so, a heart rate monitor can be programmed to alarm when approaching or exceeding this point. Careful monitoring of time spent above V/AT can assist with pacing activities to reduce symptoms consistent with post-exertional malaise.

Cardiopulmonary exercise testing (CPET) is a well-established test but requires a high level of expertise and experience to perform testing well.

Metabolic carts require routine maintenance to ensure the O2 and CO2 analyzers are measuring accurately. Workwell employs a rigorous quality control protocol, including biological validation to assure accuracy. Most testing facilities do not practice quality assurance that includes biological validation. 

It has taken decades to develop Workwell’s testing protocol and refine the interpretation of cardiopulmonary exercise testing (CPET) results for ME/CFS and other complex fatiguing conditions. Chronic and complex conditions have unique metabolic and cardiovascular profiles that require expertise to interpret.

In 2018 Workwell published a CPET methodology paper that describes how to perform a 2-day CPET protocol. This publication can be used as a guide when testing is not possible at one of Workwell’s testing sites. Before scheduling locally, it is essential to evaluate the testing facility’s quality assurance plan to ensure the equipment collects valid and reliable data. It is equally important for an expert familiar with the disability application process to interpret CPET results for your medical condition. It is not uncommon for CPET results to be incorrectly interpreted.

Workwell implements biological validation to ensure the gas analyzers are working properly.  In addition to volume and gas calibrations at rest, a healthy staff member performs quality control tests using step and ramping protocols. A step protocol evaluates VO2 (oxygen consumption), VCO2 (carbon dioxide production) and VE (minute ventilation) during steady states, and a ramping protocol measures the relationship of VO2 to workrate. Metabolic measures are added to a database for comparison over time and to determine the accuracy of the flow sensor and gas analyzers.

“Even when appropriate calibration procedures are followed, modern automated CPX systems can provide results that appear to be accurate yet may be erroneous. Biological quality control can highlight faults not detected by automatic calibration”. Scientific Statement from the American Heart Association.

About your visit

  1. Visit Workwell’s website and click the ‘Testing for Disability’ tab. Download the information packet.
  2. Complete and return paperwork included in the information packet by fax or email.
  3. Provide payment using Workwell’s payment portal, also located on Workwell’s website. Payment is required prior to scheduling.
  4. Once paperwork and payment are both received, a Workwell staff member will reach out to schedule an appointment.

The testing fee depends on risk for cardiovascular disease. Risk is determined by reviewing completed paperwork from the information packet. The fee for low- or moderate-risk patients is $2,250, and high-risk is $2,650. This includes a 2-day cardiopulmonary exercise test (CPET), a disability or other customized report, and follow up phone consultations with the patient, attorney, and/or doctors.

Most health insurance providers cover a portion of the testing fees. Medicare does not. Workwell is not a Medicare provider nor a member of any insurance group. Some patients have reported 100% coverage. The amount covered depends on the insurance company and plan.

Workwell does not bill insurance. A superbill containing current procedural terminology (CPT) and diagnosis (ICD-10) codes will be issued to each patient who submits a signed physician referral with the initial paperwork during the scheduling process.

A signed physician referral is not always required. It is necessary for high-risk patients and those planning to submit a claim to health insurance. If the patient is considered low- or moderate-risk and does not intend to submit an insurance claim, the physician referral is not required, and a superbill will not be issued.

Plan to arrive in a rested state to obtain a baseline test. This may increase the likelihood of showing a decrement between tests 1 and 2 consistent with a decreased functional capacity resulting from post-exertional malaise (PEM). If traveling from a significant distance, it can be helpful (although not required) to arrive a day early to rest. 

Some tips for minimizing stress and the impact of air travel include early arrival to the airport, wheelchair service, and pre-boarding. Other recommendations include noise-canceling headphones or earplugs, an eye mask and pillow, healthy snacks, and electrolyte drinks. Wearing compression tights or socks can promote circulation. Similar measures can be taken for a long journey by car.

If staying at a hotel, ask for a quiet, ADA accessible room (away from the ice machine and elevators). Bring earplugs or use white noise, eat healthy snacks and stay hydrated. 

In addition to the above, pre-appointment instructions with recovery tips are provided by email to each patient.

If possible, patients are encouraged to arrive 1-2 days before the appointment to rest and 1 after to recover before traveling home. 

  • Patients are not allowed to drive after the test. This is a safety measure for our patients. CPET can trigger post-exertional malaise (PEM) for individuals with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and other fatiguing conditions. This includes cognitive dysfunction or “brain fog,” which can create an unsafe situation when operating a vehicle.

Approximately 50% of patients recover to baseline within 4 days. Some take up to a week, and in rare cases longer than a month.

To speed up the recovery process, we highly recommend intravenous (IV) saline after testing. Patients who follow this recommendation have a reduced recovery time (especially those with orthostatic intolerance). This service is offered at our testing location in Flagstaff, AZ.

In addition, bathing with Epsom salts and diaphragmatic breathing can reduce the delayed recovery response from overexertion. Resting, hydrating, and minimizing activities are helpful strategies that promote recovery.