Post-Exertional Malaise: The Symptom Most Therapists Have Never Been Trained to Recognize
A few years into working with clients who have long COVID and other post-viral conditions, I started noticing a pattern that took me a while to name correctly. Someone would have a great day, where they conquered the world! Then, two days later they'd tell me they'd been in bed since. Not "tired." Flattened. Flu-like symptoms, worse cognition, sometimes days of recovery from a single hour of talking.
If this sounds familiar, you should know it has a name. It’s called post-exertional malaise.
What PEM Actually Is
Post-exertional malaise is the worsening of symptoms after physical, cognitive, or emotional exertion that would not have caused a problem before the person got sick. It's the hallmark symptom of ME/CFS, and it shows up constantly in long COVID as well. The important part for us as clinicians is the word "delayed". Since the crash doesn't always show up right away, many providers don’t realize it occurs. It often hits twelve to forty-eight hours after the exertion, and it can last for days, weeks, or in severe cases, months.
That delay is exactly why it gets missed so often, by patients and providers alike. If someone feels fine right after a session and falls apart two days later, most people (including many well-meaning clinicians) don't connect the dots. The person doesn't say "your session gave me PEM." They say "I've just been feeling worse lately," and the two events never get linked.
And critically, PEM isn't only triggered by physical exertion. Cognitive effort counts. Emotional effort counts. A hard conversation, a session that goes deep into grief or trauma, a even cognitive rehab exercises that push just a little too far past someone's current capacity can set off the same crash as physical overexertion would.
Why This Changes How We Should Practice
If you're doing cognitive rehabilitation with someone who has PEM, the old assumption that "more repetition, more challenge, more practice" builds skill faster simply doesn't hold. Pushing a client past their tolerance in a session isn't just unproductive, it can set them back for a week or longer. The work has to be paced, shorter sessions, built-in rest, orthostatic adjustments, close attention to a client's own reporting of what their limits actually are, not what we'd expect a "typical" client's limits to be.
If you're doing psychotherapy with someone who has PEM, the same caution applies to emotional intensity. That doesn't mean avoiding real, meaningful work. But, it does mean being honest with clients about the tradeoff, planning session intensity and timing with their energy capacity in mind, and not mistaking a client's caution about how hard they want to go in a session for resistance or avoidance. Sometimes it's neither. Sometimes it's someone who has learned, the hard way, exactly how much a hard session costs them physically.
This is also where outdated treatment models can do real harm. For years, some approaches to ME/CFS leaned on the idea that gradually pushing activity levels upward would help patients build back tolerance. Current clinical guidance has moved firmly away from that. One-size-fits-all incremental programs that ignore PEM are now explicitly discouraged, because for someone with true PEM, pushing past their energy envelope doesn't build capacity, it triggers a crash and can make baseline functioning worse over time.
What Actually Helps: Pacing
The alternative isn't stagnation, it's pacing. By helping someone learn their own energy limits across physical, cognitive, and emotional domains, and structuring activity (including therapy itself), we can empower them to stay within that envelope rather than repeatedly blowing past it. In practice, this often means:
Helping a client track their activities and symptoms closely enough to spot their own patterns (maybe thirty minutes of reading is fine, but sixty minutes reliably triggers a crash). Building predictable rest into a day rather than resting only after symptoms force it, which is the "boom-bust" cycle pacing is meant to break. Treating a therapy session itself as one of the exertion inputs in someone's day, not a neutral event outside their energy budget.
None of this means avoiding meaningful clinical work. It means doing that work with real information about how a client's body responds to effort, instead of assuming their nervous system works like the general population's.
Why I'm Writing This for Other Therapists, Not Just Clients
If you're a therapist reading this rather than a client, here's the honest version: most of us were never trained on this. PEM isn't standard content in graduate programs for counseling, social work, or speech-language pathology, and it's easy to mistake it for deconditioning, avoidance, or a motivation problem. But IT IS NOT THAT! A client who seems to "sabotage their own progress" by pulling back right when things are going well may not be sabotaging anything. They may be protecting themselves from a crash they've learned to see coming.
If you work with clients who have long COVID, ME/CFS, or other post-viral or energy-limiting conditions, it's worth learning to ask directly: do you notice your symptoms getting worse a day or two after physical, mental, or emotional exertion? That single question can change how you plan every session that follows.
If You're a Client Reading This
If this describes what happens to you after a hard day, a hard workout, or a hard conversation — you're not fragile, and you're not doing anything wrong. Your body is telling you something real, and a therapist who understands PEM will build a plan around it instead of working against it.
If you're in Fort Collins or Northern Colorado and looking for cognitive rehabilitation or therapy support that takes PEM seriously, I'd welcome the conversation.
