Kuns et al. (2026)
- Authors: Monica Coran Kuns, Ava-Kathleen Rybicki, Alba Azola, Josefina Casamento-Moran, Sruthi Kundur, Humbal Omar, Akshay Peddireddy, Peter Rowe, Agostina Casamento-Moran
- Institutes: Johns Hopkins University School of Medicine, Baltimore, MD, USA, University of Pennsylvania, Philadelphia, PA, USA
- Publisher: Archives of Physical Medicine and Rehabilitation
- Link: DOI
Summary
This systematic review highlights a significant gap in medical research regarding the non-physical triggers of PEM, such as emotional and cognitive exertion. By identifying that most studies stop monitoring patients after only 24 hours, it explains why current clinical data may fail to capture the full duration and complexity of patient ‘crashes.’ For patients and caregivers, this work validates the reality of PEM from mental or emotional stress and provides a roadmap for more realistic future research designs. It signals a shift toward developing accessible, real-world monitoring tools rather than relying solely on intense physical exercise tests.
What was researched?
The researchers conducted a systematic review to identify the current scientific evidence regarding the biological mechanisms and triggers of post-exertional malaise (PEM) in individuals with ME/CFS and Long Covid.
Why was it researched?
While physical exercise is a known trigger for PEM, the impact of emotional and cognitive exertion is poorly understood despite being frequently reported by patients. The study aimed to map the inconsistencies in how PEM is measured and identify what is missing in current clinical literature.
How was it researched?
The team screened 205 articles across six databases and analyzed a final sample of 79 studies. They focused on adult outpatient populations who underwent physical, cognitive, or emotional activity and had pre- and post-activity measurements of their symptoms and biological markers.
What has been found?
The analysis revealed that physical tests like the Cardiopulmonary Exercise Test (CPET) and grip strength are the most common ways to study PEM. However, fewer than ten studies investigated emotional or cognitive triggers, and fewer than ten followed participants for more than 24 hours after the trigger. The researchers also found significant inconsistencies in the types of biomarkers used to track PEM episodes.
Discussion
A major limitation in current research is the failure to include diverse functional activities that reflect daily life. The lack of long-term follow-up beyond 24 hours is a critical weakness, as many patients experience PEM symptoms that last for days or weeks.
Conclusion & Future Work
The review concludes that future research must incorporate multiple biological outcomes and accessible techniques to monitor PEM during a wider variety of activities. It emphasizes the need to study the ‘post-episodic’ recovery pathways to understand how patients actually return to their baseline.