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Words by Daisy Welsh – Integrative Exercise Physiologist

Post-Exertional Malaise (PEM) is a phrase that is often bundled in with the diagnostic packages of many chronic conditions. However, is its meaning and effect clearly understood? Hopefully this piece can offer a little more insight, clarification and validation into what it means to live with post-exertional malaise.

What is the difference between tiredness and fatigue?

The affliction of ‘tiredness’ is not a foreign concept to most people. Everyone has been tired at least once in their life. We often use the words interchangeably, however, tiredness and fatigue (or a long-lasting form of fatigue) are actually very different. Where we may feel rested or refreshed from sleeping when tired, fatigue can dig its nasty little hooks into us and leave us feeling just as exhausted after as we did before a sleep.

Fatigue has a way of seeping into every sense profile of our person. We may start to experience a deep heaviness in our physical ability, cognitive state and sensory experiences. Everything can become harder or even debilitating.

You may like to imagine it like a drop of water falling onto a piece of paper: as the water spreads, the ink starts to run, creating a blurred effect. The paper becomes a little heavier as the structure or integrity of the document becomes weaker. Although with rest, the paper dries and its strength improves a little, the overall state of the paper is still not fully recovered. 

Such as with most things in life, there is a spectrum to fatigue. On the far end of the spectrum, we see conditions like myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or long COVID where the fatigue that presents is debilitating and disabling. When we consider ME/CFS or long COVID, a hallmark symptom that differentiates between these diagnoses and ‘general fatigue’ is something called post-exertional malaise. It is important to note that post-exertional malaise is NOT the same as fatigue. So, what exactly is PEM?

Post-Exertional Malaise (PEM)

PEM is the exacerbation of symptoms as well as the reduction in capacity to function which often lasts days. It often presents when we push through our safe energy limits.

Everybody’s ‘safe energy limit’ is different. It is a zone where we can safely move through activities or through the day whilst still having some energy or ‘battery life’ left at the end of each day. The risk of PEM starts to increase as we move away from this zone, creeping into territories of ‘pushing through’ and ignoring signs that we are doing too much until we reach a point where we cannot pretend anymore.

What can we do during PEM?

Imagine your energy represented as an envelope. This envelope represents how much capacity we have and how much energy we have left to use. If the goal is to increase our energy envelope to allow more room for capacity, we want to slowly edge out the corners of our envelope. However, if we push too hard, we run the risk of tearing straight through the paper.

With rest, we can repair this rip and start again, but if we continue to push too hard and exceeding our energy limits, we continue to tear our envelope. Sometimes, this flare (or ‘rip in our energy envelope’) can last for days. When this cycle keeps happening, it can then lead to a point where it doesn’t matter how much rest or repair we are doing; over time, the integrity of our energy envelope weakens.

Therefore, we want to find the balance between slowly building capacity and edging out the corners of our envelope to create a larger window of tolerance without ripping through and pushing too hard, leading to PEM.

What can we do to prevent PEM?

Let’s think about energy and capacity. At the moment, it may feel like the size of that envelope feels quite small. Our job is to slowly edge out the corners of that envelope, creating more capacity and a larger window of tolerance. We can do this through energy management strategies, movement and exercise.

Pacing

Pacing is a word that you may have heard floating around. It’s not about doing nothing – pacing is all about working within your current available capacity, and not pushing through.

Pacing allows room for the inclusion of intentional pauses throughout your day to ensure your energy remains, rather than always pushing the boundaries of your energy envelope. This idea of doing ‘less than your maximum’ allows room for your capacity to grow. 

These pauses can take the form of many different approaches. It isn’t always about stopping and doing nothing or staying completely still (although stillness can be a very useful pacing strategy), sometimes it is just about breaking up the heavy loaded activities of your day with a few lighter activities.

A few examples may be:

• Performing 10x mindful breaths in a position that feels comfortable and safe (we have a ton of bite-sized breathwork practices over on our Patreon)
• Taking a moment to pause and look away from the screen. Try staring out the window, finding a landmark in the distance and staring at this for 20 seconds to allow the muscles of the eyes to relax
• Laying down with your legs up against the wall
• Changing positions
• Taking a moment to self-regulate in a way that feels right (we have a blog on this with 40 self-regulation methods to try, all of which take less than 10 minutes)
• Finding what you enjoy and creating space for yourself to practice in whatever form you have capacity to do so.

Remember, although sometimes it may seem like it, you are not alone. We are well-versed with PEM here at Zebras, and physiotherapy, exercise physiology, osteopathy and occupational therapy can all help increase your capacity in various ways. We are here to listen and to guide you through expanding your energy envelope in a safe and supportive way – submit an enquiry to start your journey with us.