Cardiopulmonary exercise testing

Cardiopulmonary exercise testing (CPET) is a clinical tool to evaluate exercise capacity and predict outcome in patients with heart failure and other cardiac conditions.

Two-day cardiopulmonary exercise testing (2-day CPET) is being utilized by the Workwell Foundation to measure PEM in ME/CFS patients.

Institute of Medicine (IOM) report on 2-day CPET
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)."