From the Guidelines
To manage post-exertional malaise (PEM) from new exercise, it is crucial to start with extremely low-intensity activities for very short durations, such as 5-10 minutes, and gradually increase exercise time by no more than 10% per week, while prioritizing recumbent or semi-recumbent exercises like rowing, swimming, or cycling over upright exercise. This approach is supported by the most recent guidelines, including the 2022 ACC expert consensus decision pathway on cardiovascular sequelae of COVID-19 in adults 1. When initiating exercise, it is essential to monitor symptoms and adjust the intensity and duration accordingly.
Key Principles for Managing PEM
- Begin with low-intensity activities that allow for conversation in full sentences
- Gradually increase exercise duration by 2 minutes per day each week
- Prioritize recumbent or semi-recumbent exercises to avoid worsening fatigue
- Avoid upright exercise initially, as it can exacerbate orthostatic intolerance and postexertional malaise
- Implement pacing strategies, breaking activities into smaller segments with rest periods between them
Importance of Pacing and Monitoring
Pacing is critical in managing PEM, as it helps avoid triggering debilitating symptom cycles. Heart rate monitoring can be helpful, but the primary focus should be on symptom management and gradual progression of exercise intensity and duration. If symptoms occur, it is essential to rest completely until they resolve before attempting activity again, potentially at an even lower intensity. This cautious approach is necessary to prevent worsening fatigue and promote safe rehabilitation, especially in conditions like Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID, where the body's energy production systems and stress response are dysregulated after exertion 1.
From the Research
Post-Exertional Malaise from New Exercise
- Post-exertional malaise (PEM) is a worsening of symptoms after physical or mental exertion, and is considered a central feature of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) 2, 3, 4.
- Studies have shown that patients with ME/CFS experience a wide range of symptoms after exertion, including exhaustion, cognitive difficulties, and neuromuscular complaints 2, 3.
- The onset of PEM can be immediate or delayed, and can last from a few days to several months 3.
- Research has also shown that repeated exercise on successive days can lead to altered muscular metabolism and autonomic nervous responses in patients with ME/CFS 3.
- A study examining the effects of exercise on cerebrospinal fluid metabolomics-lipidomics and serine pathway in ME/CFS found significant differences between ME/CFS and control groups, indicating disease-related pathologies 5.
Characteristics of Post-Exertional Malaise
- PEM is often triggered by physical or mental exertions, and can interfere with a person's ability to lead a "normal" life 2, 3.
- Patients with ME/CFS describe PEM as all-encompassing, with symptoms affecting every part of the body, and difficult to predict or manage 2.
- The experience of PEM can vary greatly between individuals, and can lead to a diminished quality of life 2.
- There is a need for further research to better understand the processes occurring in the restitution period following exercise, as PEM reaches its peak in this phase 3.
Rehabilitation and Treatment
- Effective interventions for fatigue and exercise intolerance include exercise training and physical activities, telerehabilitation, and multicomponent and educational interventions 6.
- Combined aerobic/anaerobic training and integrated disease rehabilitation management have also been shown to be effective in improving exercise intolerance 6.
- However, the overall quality of evidence for these interventions is often low to very low, and more research is needed to develop effective treatments for PEM and other symptoms of ME/CFS 6.