Activity management based on 2-day cardiopulmonary exercise testing results

The results from a two-day cardiopulmonary exercise test can help ME/CFS patients manage their activity levels in order to minimize post-exertional malaise (PEM).

Theory
In "Conceptual model for physical therapist management of chronic fatigue syndrome/myalgic encephalomyelitis" by Todd E. Davenport,  Staci R. Stevens,  Mark J. VanNess,  Christopher R. Snell, and Tamara Little, recommendations are divided into two categories: pacing self-management and therapeutic exercise.

Pacing self-management focuses on staying below the anaerobic threshold (AT) heart rate, as determined by a 2-day CPET. Strategies include wearing a heart rate monitor, frequent breaks including diaphragmatic breathing, alternate positions, and use of adaptive equipment, and keeping an activities log to further identify activities that induce post-exertional malaise PEM.

Therapeutic exercise is designed to prevent excessive use of the aerobic respiration system. They recommend starting with stretching and active range of motion exercises. When these are well tolerated without triggering PEM, the patient can move on to strength training: short duration, low intensity strengthening exercises with adequate rest intervals. Finally, patients can advance to short duration, low intensity interval training. Patients who can tolerate this can move on to short-duration aerobic interval training.

In all these stages, interval duration should be under 2 minutes, and the heart rate kept at 10% below the AT. The paper stresses caution and slow changes, as tolerated.

In the absence of 2-day CPET results, they suggest 3 methods of estimating the anaerobic threshold (AT) heart rate:
 * estimating the AT from V̇o2max measurements obtained during submaximal exercise testing;
 * the heart rate corresponding to Borg Rating of Perceived Exertion ratings of 13 to 15 during submaximal exercise testing may be used.
 * estimating the heart rate at AT by calculating 55% of the HR at the V̇o2max as a starting point, although specific establishment of the HR at the AT in this population requires additional research. In the general population, this is calculated by the formula (220-age) * 0.55.

In "Functional Outcomes of Anaerobic Rehabilitation in a Patient with Chronic Fatigue Syndrome" by Staci Stevens and Todd Davenport recommendations for an ME/CFS patient were again divided into two categories, pacing self-management and therapeutic exercise.

Pacing self-management focused on keeping the heart rate below the ventilatory threshold, and using diaphragmatic breathing.

Restorative strengthening and flexibility exercises were recommended as follows:
 * keeping the heart rate below the AT;
 * 3 times weekly;
 * exercises were done lying down

At the one year follow-up, the patient showed 75% improvement in the time it took her to recover from the 2-day CPET itself. She also reported increased ability to complete daily activities.

Evidence

 * Case report on one-year follow-up of patient who was given a rehabilitation program after a 2-day CPET, and descriptive article by Cort Johnson on the study, providing additional information

Clinicians

 * Staci Stevens at the Workwell Foundation, California, US.
 * Betsy Keller at Ithaca College, New York, US.

Risks & safety
Although the Institute of Medicine (IOM) report states that 2-day CPET is very reliable to objectively measure post-exertional malaise 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)."

Costs & availability
2-day CPET testing is available at the following locations:
 * Workwell Foundation (California, United States)
 * Betsy Keller at Ithaca College (New York, United States) - 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.
 * Charles Lapp at the Hunter-Hopkins Center in Charlotte, NC
 * Laura Black in the Hunter-Hopkins Center in Charlotte, NC