Disclaimer: This information is for educational purposes and not a substitute for personalised medical advice. Always consult your healthcare provider for assessment and treatment tailored to you.
Many people living with Long Covid describe the frustrating and unpredictable experience of feeling “better one day and then worse the next.”
For example, you might manage a short walk or a morning of emails only to find yourself flattened by fatigue in the afternoon.
This unpredictable pattern is known as the boom-and-bust cycle, and we would like to let you know that it’s not a lack of willpower or motivation. It’s often a sign of what we call post-exertional malaise (PEM). PEM is a hallmark symptom of Long Covid and other post-viral conditions.
At the Apheresis Centre, we work with patients who experience these debilitating fluctuations and help them build stability through approaches like pacing and individualised therapy programmes. This guide explains what pacing is, why it matters, and how to start applying it safely.
What Is Post-Exertional Malaise (PEM)?
Post-exertional malaise means your symptoms worsen after activity, not only physical effort but also mental or emotional strain. Commonly, the crash happens 12–48 hours after the triggering activity and can last days or even weeks.
Activities as small as folding laundry, reading emails, or attending a social event can trigger fatigue, brain fog, or pain well beyond what seems reasonable.
Learn more about the biology behind this in our post Why You Still Feel Sick: The Hidden Biology of Long Covid.
How PEM Feels (and How It’s Different from Normal Tiredness)
Common PEM Symptoms
- Sudden or delayed exhaustion.
- “Brain fog” or slowed thinking.
- Muscle heaviness or weakness.
- Flu-like feelings.
- Sleep that doesn’t restore energy.
Fatigue vs. PEM
- Normal fatigue: improves with rest → PEM: can persist even after sleep.
- Exercise: helps fitness → Exertion: worsens PEM.
- Effort: PEM symptoms are disproportionate to what you did.
Why PEM Happens in Long Covid
Current research suggests Long Covid affects how our cells produce and store energy, how the nervous system regulates stress responses, and how microclots and inflammation disrupt recovery. This mismatch means your body can’t “bounce back” after exertion, which leads to the cycle of collapse.
What Is Pacing?
Pacing Explained
Pacing means balancing your activity with your available energy and staying within your “energy envelope.” Instead of reacting after a crash, you plan rest before symptoms appear.
What Pacing Is Not
- Not graded exercise therapy.
- Not “pushing through” fatigue.
- Not permanent avoidance of all activity.
Pacing is about self-regulation, not surrender. It helps your body stabilise so that recovery can happen progressively and safely.
Signs You Might Benefit from Pacing
- You feel worse 12–48 hours after activity.
- You experience “good days” followed by a crash.
- Mental focus causes physical exhaustion.
- Sleep doesn’t fully restore you.
If this sounds familiar, talk to your doctor. This isn’t a diagnosis, but a helpful pattern to discuss.
Common Triggers That Can Cause a PEM Crash
Physical Triggers
- Walking too far.
- Standing for long periods.
- Household chores.
Cognitive & Emotional Triggers
- Screen time.
- Concentration-heavy tasks.
- Stressful or emotional interactions.
Read about managing heat or environmental triggers in our post Managing Long Covid Heat Intolerance in the Heat of Summer.
How Basic Pacing Works in Daily Life
Core principles
- Breakdown tasks into easy-to-manage steps.
- Schedule rest breaks before you feel fatigue setting in.
- Prioritise essential tasks and reschedule the rest.
- Keep a Symptom Diary to identify patterns.
Energy as a limited resource
Think of your energy like a battery or a budget. Once the battery is empty and fatigue sets in, it’s going to take longer to recharge. Planning around your “available charge” keeps you more stable across the week.
Why pacing can feel counterintuitive
We’re taught that pushing through tiredness builds strength. But with PEM, this approach delays healing. Feeling “lazy” or “stuck” is normal when dealing with chronic illness, but pacing isn’t weakness; it’s about strategy. By staying within your personal limits, you give your body the conditions and energy it needs to recover.
Why is Pacing Crucial for Long COVID?
Long COVID is a complex condition that often affects multiple systems in the body, leading to symptoms like profound fatigue, brain fog, and shortness of breath. Many individuals experience a boom-and-bust cycle: feeling slightly better, pushing too hard to catch up on activities, and then crashing due to overexertion. This cycle not only delays recovery but can also worsen symptoms over time.
Here’s what pacing does for recovery:
- Prevents Post-Exertional Symptom Exacerbation (PESE): By avoiding overexertion, pacing minimises the risk of symptom flares caused by physical, mental, or emotional strain.
- Conserves Energy: It ensures that limited energy reserves are used efficiently, leaving enough capacity for essential tasks and recovery.
- Supports Healing: Adequate rest and measured activity levels help reduce systemic stress and give the body time to repair and restore itself.
- Reduces the Boom-and-Bust Cycle: Pacing helps break the pattern of overactivity followed by crashes, stabilising energy levels and fostering gradual improvement.
- Improves Symptom Management: By staying within the “energy envelope,” individuals can better manage symptoms like fatigue, brain fog, and physical weakness.
- Enhances Mental Health: Pacing can reduce frustration, guilt, and anxiety associated with pushing too hard, leading to a more positive outlook on recovery.
- Builds Resilience: It helps individuals learn their limits, which can lead to a more sustainable and proactive approach to managing their condition.
Ultimately, pacing is about respecting your body’s current capacity, which creates the conditions for more steady and long-term recovery.
Recognising Your Energy Boundaries
The first step in pacing is understanding your unique energy boundaries. These boundaries are often dynamic and can vary from day to day, depending on factors like sleep quality, stress levels, and symptom severity. Recognising early warning signs of overexertion is key to staying within your energy envelope.
Common signs that you may be approaching your limit include:
- Increased heart rate or shortness of breath.
- Difficulty concentrating or heightened brain fog.
- A sense of heaviness or weakness in your body.
- Feeling irritable, overwhelmed, or emotionally drained.
Keeping a journal of your daily activities and symptoms can help you identify patterns and triggers. Over time, this practice allows you to better anticipate when you need to slow down or rest.
Overcoming Common Challenges with Pacing
Pacing is a simple theoretical concept, yet it often requires a big shift in mindset, especially if you’re used to being highly active or productive. It’s common to feel frustrated or guilty about needing to slow down. You may even feel you’re slowing down so much, but you’re not meeting your body’s current capabilities just yet. This is why pacing holds a key space in health coaching for Long COVID.
Here are some tips to overcome these challenges:
- Be Kind to Yourself: Acknowledge that pacing is a necessary part of your recovery and not a sign of weakness.
- Celebrate Small Wins: Recognise and appreciate your progress, no matter how small.
- Seek Support: Seek professional support on how to apply pacing to your personal health situation and recovery journey.
When Should You Speak to a Doctor
You should seek professional support if:
- Symptoms persist beyond 4–8 weeks after infection.
- Crashes are severe or worsening.
- Fatigue is interfering with work duties or daily functioning.
Documenting your activity with an activity/symptom diary can help your clinician identify triggers and suggest tailored therapies.
Pacing and Long-Term Recovery
Pacing lays the foundation for recovery, but it’s not the endpoint. Stabilising energy allows other forms of treatment, including vascular and autonomic therapies, to work more effectively.
Recovery from Long Covid is rarely linear. We have found that with the right guidance and planning, setbacks can become less frequent and less intense.
Discover our holistic approach in Comprehensive Long Covid Therapy at The Apheresis Centre.
FAQ: Pacing and PEM
Is PEM the same as chronic fatigue?
No. PEM describes symptom worsening after exertion instead of general tiredness. It’s commonly seen in Long Covid and ME/CFS.
Can pacing make me weaker?
No. Avoiding crashes protects your system and helps maintain a sustainable baseline.
How long should I pace for?
There’s no set timeline. Continue until your post-activity recovery becomes more predictable.
Can mental effort trigger PEM?
Yes. Concentration on difficult tasks, highly emotional conversations, or decision-making can be just as draining as physical tasks.
Author / Medical Review Note
Written by Andrew Smith, reviewed by Dr Inbar Tofan, Medical Director at The Apheresis Centre, who has over 10 years of experience in chronic illness care and post-viral recovery medicine.
