What is Post-Exertional Malaise (PEM)?

The definition of post-exertional malaise (PEM), also known as post-exertional symptom exacerbation or post-exertional neuroimmune exhaustion, is the often delayed worsening of symptoms after minimal physical or mental activity. These symptoms can include debilitating fatigue, body pain, muscle weakness, and cognitive dysfunction. Symptoms often appear 24 hours after physical or mental activity, but the symptoms are not in proportion to the activity. For example, you may feel good today and decide to go for a walk around the block. You feel fine afterward but when the next day hits, you are overwhelmed by symptoms.

PEM is not the same as fatigue or exhaustion. Many patients describe post-exertional malaise as hitting a wall. The body just doesn’t function. You are physically and mentally spent and, in many cases, may be confined to bed for days after a simple activity. And it isn’t just physical activities that can trigger PEM. Cognitive overexertion or sensory overload can trigger PEM, as well as environmental changes like dramatic shifts in temperature or air pressure before a storm. While healthy people can easily adapt to these changes, they can cause PEM in severe patients.

While the definition of post-exertional malaise states that any physical or mental demand on the body can trigger an increase in symptoms, triggers can be much more than that. In severe cases, even basic bodily functions, such as breathing and blood circulation, can produce an energy expenditure that is simply too much for the body to process, resulting in increased symptoms. This can make basic self-care impossible, let alone the idea of participating in normal daily activities.

Physical activities are not just exercise-based. Physical exertion can occur by performing simple daily functions such as a shower, cleaning the house, or simply driving to a doctor’s appointment or grocery shopping. Even the smallest amount of exertion can trigger PEM when disease presentation is severe.

Each individual person experiences different symptoms when they trigger PEM. However, researchers asked a study focus group to explain their symptoms of PEM. While they all describe symptoms as all-encompassing with symptoms affecting every part of their body, common symptoms, with varying intensity, include:

The goal of PEM treatment is to avoid triggering a PEM episode. Because triggers are different for everyone, this means treatment must be very individualized. For those with PEM, keeping a diary may be beneficial to help identify triggers to try avoiding them when possible. Unfortunately, many times some of your triggers are unavoidable, so identifying other triggers helps you avoid multiple triggers at the same time. Oftentimes, changes in heart rate can indicate a potential trigger, so investing in a wearable device that measures heart rate can be beneficial.

“Start exercising and you will feel better.” Unfortunately, many people with chronic medical conditions often hear from their physicians that exercise is all they need to help reduce their symptoms. The reasoning behind this is that when a body doesn’t move, deconditioning occurs. Deconditioning is a decline in physical and/or psychological function due to long periods of inactivity. However, PEM is NOT a form of deconditioning! And while exercise does help those with deconditioning, exercise can make someone with PEM so much worse.

Most specialists agree that people with post-exertional malaise should be as active as they are able without exacerbating their symptoms to reduce the risk of muscle atrophy and aid in digestion, metabolism, and circulation. While some people may find help with gentle exercise as they improve, others do not. It all boils down to the limits of the individual.

We will discuss pacing below as a way to balance your activity and rest. However, you may find some physicians still push for exercise, as the old standard was to treat people with post-exertional malaise using graded exercise therapy. However, we now know that this form of therapy, while it may be beneficial for other chronic conditions, is detrimental to those with PEM. There is, however, something you can do to help improve your cardiovascular and muscle strength without too much physical exertion.

For most people, normal breathing tends to be shallow and does not utilize the full capacity of the lungs. Diaphragmatic breathing, also known as belly breathing, is an exercise technique that fully engages your diaphragm and stomach muscles while helping to increase your lung efficiency. This breathing exercise helps to strengthen the diaphragm, improves core muscle stability, helps slow your breathing rate, heart rate, and blood pressure, increases available oxygen to the body, and promotes relaxation. Practicing diaphragmatic breathing a few times a day can greatly improve your endurance and muscle strength and it is easy enough that you can perform this exercise in bed. Follow these steps:

Practicing diaphragmatic breathing in this way for 5-10 minutes, three to four times a day is beneficial. When you become comfortable with this exercise, consider trying this breathing technique while sitting or standing. This is a great way to take time out during your day to focus on breathing, rest, and recover as you will learn in pacing.

Pacing is a treatment strategy that helps you establish a balance between rest and activity in order to help you conserve energy reserves and avoid pushing yourself past your limit. By using pacing techniques, you can help reduce the occurrence and severity of PEM symptoms and relapses. With the regular use of pacing, many people can, over time, increase their functional capacity. Pacing is a key treatment for those with post-exertional malaise and it is essential to understand the concepts in-depth. Therefore, we will focus an entire post on pacing, how it works, and the benefits it provides.