Imagine living with a chronic fatigue condition for months, or even years. You know that movement is key to your recovery and you are motivated to do it, but every time you try, it feels like taking one step forward and three steps back.
The societal messaging around exercise tells you that to get better, you have to push through – that eventually, your body will adapt, grow stronger, and regain its energy. Yet, every attempt leaves you feeling worse. Before long, the very idea of exercise stops feeling like a solution and starts feeling like a threat.
This frustrating phenomenon is a distinct medical symptom known as Post-Exertional Malaise (PEM). It is a hallmark feature of chronic fatigue-based conditions, including ME/CFS, Long COVID, Fibromyalgia, and Post-Viral Fatigue. Our role as exercise physiologists working within the chronic fatigue space is to provide our clients with the tools to manage PEM, so that they can still gain the many benefits of exercise.
What is Post-Exertional Malaise (PEM)?
PEM is a severe worsening of symptoms following minimal physical, mental, or emotional activity. It is fundamentally different from the normal tiredness someone feels after a tough workout or stressful day at work. Normal fatigue is proportional to effort and goes away with a good night’s rest. PEM, however, is a systemic crash. It can be triggered by everyday tasks like a short walk, grocery shopping, or even an hour of screen time.
Common signs of a PEM “crash” include:
- Exhaustion that doesn’t recover with sleep
- Brain fog and difficulty concentrating
- Muscle aches and joint pain
- Flu-like symptoms (sore throat or swollen glands)
- Sensitivity to sound, light or touch.
PEM may occur during or immediately following the triggering activity, or it may present several days after. This can make it difficult for people to understand exactly what is causing their symptoms, often resulting in a rollercoaster ride of accidentally pushing too far, then being forced to rest.
The Danger of the “Push-Crash” Cycle
In traditional workplace rehabilitation, we often encourage clients to build tolerance by gradually doing a little more each session. When PEM is present, this approach backfires.
When clients try to push through fatigue, they enter a destructive push-crash cycle. Many people try to take advantage of a “good day” by overdoing activity, only to spend the next few days, or even weeks, incapacitated. If we allow our clients to push through fatigue to complete an exercise session, we are reinforcing this “Push-Crash” cycle. Repeatedly crashing can lower a client’s baseline functional capacity, meaning that they will start to crash at lower levels of exertion. Simply said, they start getting worse, not better.
Given that our role as exercise physiologists involves exercise (i.e. one of the biggest PEM triggers!), we need to have a clear understanding of PEM and how it affects that individual.
Screening for PEM: 6 Questions to Ask
Symptoms of PEM can vary from one person to another. Before starting a physical rehabilitation program, it can be helpful both for the clinician and client to have a clear understanding of their symptom presentation and any known triggers. These 6 questions outlined in the ‘Clinical Care Guide’ by Bateman Horne Center can be used to paint a comprehensive picture:
- What happens after you do activities you used to handle easily? Do you get new symptoms like brain fog, dizziness, or flu-like feelings?
- How do you feel during physical or mental tasks? Do you notice immediate signs of overexertion?
- Do you experience a “payback” later? Does a crash hit you 12 to 48 hours after the activity, even if you felt fine while doing it?
- How long does it take to recover? Are you out of action for days, weeks, or longer before getting back to your baseline?
- What specific activities trigger this response?
- Do you experience push-crash cycles? Do you find yourself overdoing it on good days, only to pay for it later?
Client Apprehension Around Exercise
Navigating daily life with a complex chronic fatigue condition is hard enough, so adding physical rehabilitation on top of all the usual daily stressors can feel like trying to climb Everest! Clients often face immense uncertainty around how much they can do before exacerbating symptoms, with previous negative experiences of exercise ringing alarm bells in their mind. This unpredictability leaves many feeling understandably reluctant to engage in rehabilitation programs for fear that a session will trigger a severe relapse.
The Specialised Health Approach
The Specialised Health approach to fatigue management is deeply rooted in an understanding of PEM. It’s not just about exercise – our programs also take into account the many other daily activities that contribute to PEM. We use objective data to create clarity amidst the fog of symptoms. This data guides our exercise programming, allowing us to create a plan that is fluid, adaptable, and responsive to the changing needs of our clients.
Check out our next blog in 2 weeks time, which delves deeper into the Specialised Health approach and how we work around PEM!
References:
- https://emerge.org.au/post-exertional-malaise-pem/
- https://batemanhornecenter.org/wp-content/uploads/2025/05/Clinical-Care-Guide-First-Edition-2025-1.pdf
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