CPET – Cardiopulmonary Exercise Test

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What are the Signs of Post-exertional Symptom Exacerbation Among Patients with ME/CFS or Long COVID?

Patients with ME/CFS or Long COVID

If you have Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) or Long COVID, you may be susceptible to post-exertional symptom exacerbation (PESE). 


PESE worsens symptoms and decreases function following physical, cognitive, or emotional effort. PESE, also referred to as post-exertional malaise, is a hallmark of ME/CFS and is commonly found in people with long COVID. PESE/PEM results from a damaged aerobic energy system and overdoing activities that exceed the “energy envelope,” which varies from person to person and level of disease severity.


The onset of PESE/PEME may occur immediately after activity but is often delayed by a day or more. This makes PESE/PEM challenging to manage.


This blog post highlights signs indicating PESE/PEM and how to manage the symptoms.


What are the Symptoms of PESE/PEM?

Understanding the signs and symptoms of PESE/PEM is crucial to effectively manage ME/CFS and long COVID. 

Our research has identified a time course for PESE/PEM, including immediate, short-term, and long-term symptoms. Symptoms after physical activity result from exceeding the “ventilatory/anaerobic threshold” – the point at which the body starts to shift from using oxygen to produce energy to a much less efficient anaerobic energy production pathway. PESE/PEM can also occur in response to mental exertion and stress though the effects of these aspects of PESE/PEM are less studied than responses to physical activity. 

Identifying the early signs of PESE can help patients avoid “crashes.” Some immediate symptoms include shortness of breath, dizziness, and nausea. To learn more about PESE/PEM, see our PEM Timecourse.


Crashes resulting from PESE/PEM can last for days, weeks, or sometimes months. 

Symptoms of short- and long-term PESE/PEM may include the following:


  • Fatigue that persists for days following physical activity


  • Cognitive dysfunction (brain fog)


  • Headaches


  • Sleep problems, including trouble falling asleep or staying asleep


  • Gastrointestinal symptoms 


  • Orthostatic and neurologic symptoms


  • Worsening pain


  • Decrease in mood


  • Weakness


  • Flu-like symptoms


How the Workwell Foundation Can Help

Workwell Foundation uses 2-day cardiopulmonary exercise testing (CPET) to assess maximal aerobic capacity and determine submaximal sustained exercise performance. 


CPET provides valuable information to identify the origins of aerobic energy impairment and unexplained shortness of breath in people experiencing multiple chronic comorbidities.

After testing, we’ll ask you evidence-based questions that may indicate PESE/PEM. 

These include, 


  • “Does it take more than one day to recover to your usual baseline from activity?”, 
  • “Do you feel unwell, weak, don’t sleep well, or have pain when recovering from an activity?” 


We’ll also provide guidelines for symptom management, such as pacing activities with a heart rate monitor to regain control of your well-being.

Call us at 661-466-2545 to learn more.


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