Long COVID pacing: how to manage your energy and avoid post-exertional crashes
Pacing is currently the recommended approach for managing post-exertional malaise (PEM) in Long COVID. What PEM is, why 'just exercise more' backfires, and how some people use resting heart rate and HRV as one of several signals for their daily energy planning.
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If others tell you to "just do more" or "ease back into activity" - and you find yourself bedridden for days afterward - you are not alone, and you are not doing anything wrong. Those crashes have a name: post-exertional malaise (PEM). And the answer is not more activity, but a deliberate strategy called pacing. Sam cannot offer you a formula for it - but at no cost and with no extra effort on your part, it shows you the markers that some people use to assess their own capacity.
Understanding post-exertional malaise (PEM)
Post-exertional malaise is not ordinary muscle fatigue or "having a bad day." The German Society for ME/CFS defines PEM as a pathological, often significantly delayed worsening of all symptoms - usually 24 to 72 hours after minimal physical, cognitive, or even emotional activity. It might be a short walk, a demanding phone call, or a single day of sensory overload. The German term Belastungsintoleranz (activity intolerance) describes the same thing and is used, for example, by the Charité Fatigue Center.
That delay is what makes PEM so deceptive. The trigger often happens two or three days before the crash begins - making cause and effect difficult to connect without careful observation.
Why "pushing through" or structured exercise backfires
For years, people with chronic fatigue - including those with ME/CFS, long before Long COVID existed - were told to gradually increase their activity (Graded Exercise Training, GET), with the goal of raising their activity threshold over time. That recommendation is now considered outdated and potentially dangerous. Escalating exercise approaches can cause severe, sometimes lasting deterioration rather than improvement.
PEM differs fundamentally from ordinary post-illness fatigue: any increase in activity leads to worsening, not improvement. If someone recommends a structured activity ramp-up, seek a second opinion from someone with PEM expertise - a post-COVID clinic or a fatigue center.
Pacing as the currently recommended approach
Because no curative treatment for PEM exists yet, health agencies worldwide endorse pacing as the current strategy: distributing your energy and activity so you remain within your personal energy ceiling - often described as an "energy account" or "battery" - to avoid crashes.
In practice, this means many people break activities into smaller units and rest deliberately - before they feel exhausted, not after. If an unavoidable event (like a doctor's appointment) is coming up, some people plan extra rest days before and after it. But the underlying principle stays the same: don't exceed your activity threshold. Long COVID Deutschland and the AWMF patient version of the clinical guideline offer detailed, concrete pacing instructions.
Where resting heart rate and HRV fit - and where they do not
Some people include resting heart rate and heart-rate variability as one of several signals in their daily planning. The idea: a resting heart rate that is higher than usual despite minimal activity, or unusually low HRV on a given day, might signal reduced energy reserves that day.
A UK feasibility study (Clague-Baker et al., 2024) tested continuous heart-rate monitoring as a pacing aid in 47 people with Long COVID and ME/CFS. The result: 89% continued the approach after eight weeks, and 66% after six months - high acceptability. Importantly, this was a feasibility study of user acceptance, not proof that HR monitoring reliably prevents PEM.
What that means: Resting heart rate and HRV are not a reliable crash alarm. They can - as part of a larger picture that includes symptom logs, activity planning, and how your body feels - help inform your own assessment. Whether and how you use them is best discussed with your care team.
Where Sam Health fits in
Sam reads resting heart rate, HRV, sleep, and activity from Apple Health and shows you your patterns against your personal baseline - passively, without requiring you to manually log numbers on an exhausting day. To set up your iPhone and Apple Watch for this, see the guide How to set up Apple Watch for Long COVID.
Try Sam HealthAbout Sam
Sam is a wellness companion, not a medical device. Sam does not diagnose, treat, or prevent any illness and does not replace medical advice. For health questions, always consult a qualified medical professional. No wearable or app - including Sam - can reliably predict or prevent PEM. Pacing remains your responsibility and requires guidance from clinicians familiar with PEM and ME/CFS.
Sources
- German Society for ME/CFS: Post-Exertional Malaise
- Long COVID Deutschland: Information for Patients and Families
- AWMF: S1 Guideline Long/Post-COVID Syndrome, Patient Version
- Clague-Baker et al. (2024): Feasibility study of continuous heart-rate monitoring as a pacing support tool for Long COVID and ME/CFS
Frequently Asked Questions
What is post-exertional malaise (PEM)?+
PEM is not ordinary tiredness after exertion. It is a pathological, often significantly delayed worsening of all symptoms - usually 24 to 72 hours after minimal physical, cognitive, or emotional activity. This definition comes from the German Society for ME/CFS and aligns with international diagnostic criteria.
Is exercise the answer to Long COVID?+
No. Escalating-activity approaches like the older 'Graded Exercise Training' (GET), designed to gradually push the activity threshold higher, are now known to be harmful for people with PEM and can cause severe, sometimes lasting setbacks. For suspected PEM, activity should never be increased without guidance from a clinician experienced in PEM or ME/CFS.
What exactly is pacing?+
Pacing means distributing your energy and activity so you stay within your personal energy ceiling - the level beyond which you trigger crashes. Health agencies worldwide recommend pacing as the current strategy for ME/CFS and PEM because no curative treatment exists yet.
Can a smartwatch tell me when to stop?+
No. A smartwatch can show resting heart rate and HRV, but it cannot reliably warn you before a crash. Some people use these numbers as one of several factors in planning their day - though there is no scientific validation yet that heart-rate monitoring can predict PEM.
What is activity intolerance in Long COVID?+
Activity intolerance is another name for post-exertional malaise (PEM): a pathological, often delayed worsening of all symptoms after physical, cognitive, or emotional exertion. The term is used, for example, by the Charité Fatigue Center and describes the same phenomenon as PEM.
Why is exercise risky when it is usually healthy?+
Because with PEM, any increase in activity leads to worsening symptoms rather than fitness gains. That is why the older step-by-step training approach (Graded Exercise Training) is now considered outdated and potentially harmful for people with PEM.