Pacing vs Graded Exercise for ME/CFS: Understanding the Evidence and the Controversy
One of the most significant reversals in modern medicine occurred in 2021 when the UK’s National Institute for Health and Care Excellence (NICE) withdrew its recommendation for graded exercise therapy (GET) for ME/CFS—also known as Chronic Fatigue Syndrome. This wasn’t just a minor guideline update. It represented a fundamental shift in how we understand and manage this debilitating condition affecting an estimated 240,000 Australians.
For decades, patients with ME/CFS were told that gradual increases in exercise would help them recover. Many were blamed when this approach didn’t work, or worse, when it made them significantly worse. Now, international guidelines recommend a completely different approach: pacing, also called energy management.
So what changed? And what does this mean for people living with ME/CFS?
What is ME/CFS?
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex chronic illness characterised by severe fatigue that doesn’t improve with rest. But the defining feature that separates it from simple fatigue is something called post-exertional malaise (PEM).
PEM means that physical, cognitive, or emotional exertion that would be manageable for a healthy person triggers a worsening of symptoms that can last days, weeks, or even months. This isn’t the normal tiredness after exercise that improves with rest—it’s a systemic crash that can be profoundly debilitating.
What is Pacing?
Pacing, or energy management, is a strategy that helps people with ME/CFS stay within their energy limits to avoid triggering post-exertional malaise. The fundamental principle is simple: stop activity before symptoms worsen, rather than pushing through until you crash.
Core principles of pacing include:
- Finding your baseline: Track activities and symptoms for 2-3 weeks to identify patterns and determine how much activity you can manage without triggering PEM
- The 50-60% rule: Do only 50-60% of what feels possible on any given day—this provides a buffer to prevent crashes
- Stop before symptoms increase: Don’t wait until you feel worse; stop activity before you hit that point
- True rest: Minimise all sensory, cognitive, and emotional stimulation—this means no TV, reading, or scrolling on your phone during rest periods
- Pre-emptive rest: Rest before anticipated exertion, not just after
- All activity counts: Physical, cognitive, emotional, and social activities all draw from the same energy pool
A practical example:
Sarah has ME/CFS, and her resting heart rate is 65 beats per minute. Using the Workwell Foundation formula (resting heart rate + 15), her target threshold is 80 bpm. She wears a heart rate monitor set to alert her when she reaches 80 bpm. When shopping at the supermarket, her heart rate alarm sounds. Rather than finishing her shopping, she immediately stops, sits down, and rests until her heart rate returns to baseline. She may need to return later or ask someone else to complete the shopping—and that’s okay. This is pacing in action.
What is Graded Exercise Therapy?
Graded Exercise Therapy (GET) was based on the theory that ME/CFS is caused or maintained by deconditioning and unhelpful illness beliefs. The approach involved gradually increasing physical activity according to a predetermined schedule, regardless of symptoms.
A typical GET program might look like:
- Week 1: Walk for 5 minutes daily
- Week 2: Walk for 7 minutes daily
- Week 3: Walk for 10 minutes daily
- And so on, with increases every week or two regardless of how the person feels
The critical difference from pacing is that GET follows a fixed schedule of incremental increases, while pacing is symptom-contingent—meaning it adjusts based on how you’re actually feeling and performing.
The Fundamental Difference
The key distinction between pacing and GET lies in who controls the activity level:
With GET: The schedule controls the activity level. If you feel worse, you’re encouraged to continue the program because symptoms are seen as a psychological barrier to overcome rather than a physiological warning signal.
With pacing: You control the activity level based on your body’s signals. If you feel worse, you reduce activity because symptoms indicate you’ve exceeded your current energy capacity.
What Does the Evidence Show?
Evidence for Pacing
The most rigorous meta-analysis of pacing interventions, published in 2022, reviewed 14 randomised controlled trials. The findings showed that pacing produced moderate improvements in fatigue (effect size of -0.52), physical function, and depression compared to no treatment or usual care.
Importantly, across all studies examined, pacing showed no adverse events—no one got worse from pacing. This safety profile is crucial for a condition where the wrong intervention can cause significant harm.
A 2025 Australian study of self-paced aquatic exercise in 32 people with ME/CFS found a 13.7% improvement in walking ability with no adverse events. The key was that participants controlled their own intensity and duration—essentially implementing pacing principles in an aquatic environment.
The Problem with GET Evidence
The evidence for GET seemed strong—until researchers took a closer look. The landmark PACE trial, published in The Lancet in 2011, claimed that GET and cognitive behavioural therapy (CBT) produced ~60% improvement rates. This £5 million study from six UK clinics was considered definitive evidence.
But there were serious problems:
1. Outcome measures were changed mid-trial
The researchers lowered the threshold for what counted as ‘recovery’ after the trial started. This meant that 13% of participants met both the entry criteria for being disabled AND the criteria for ‘recovery’ at the same time—before receiving any treatment. Imagine a trial where people are considered both too sick to participate and already recovered simultaneously.
2. Objective measures showed no improvement
While participants reported feeling better on questionnaires, objective measures told a different story:
- Six-minute walk test: Minimal improvement
- Activity monitors: No significant change in actual activity levels
- Employment status: More people on disability benefits after treatment than before
3. The trials weren’t blinded
Participants knew which treatment they were receiving, and all outcomes were based on subjective questionnaires. This creates significant bias—if you’re told an exercise program will cure you and you’ve invested months in the program, you’re more likely to report improvement even if your actual function hasn’t changed.
4. Patient-reported harms were ignored
While the original PACE trial reported minimal adverse events, patient surveys tell a very different story. Studies have shown that 58-81% of people with ME/CFS report worsening after GET. This massive discrepancy suggests systematic underreporting of harms in the clinical trials.
The Reanalysis
After a lengthy Freedom of Information battle (during which the university spent approximately £250,000 resisting data release), researchers finally obtained the raw PACE trial data. When analyzed using the original, pre-specified outcome measures, the results were dramatically different: only 7% of GET participants and 5% of pacing participants met recovery criteria—compared to the 22% claimed in the published paper.
This revelation led to one of the most significant evidence reversals in modern medicine.
What Do Current Guidelines Recommend?
Based on the reanalysis of evidence and recognition of patient harms, international guidelines have shifted dramatically:
NICE (UK), 2021: ‘Do not offer’ graded exercise therapy. Recommends energy management (pacing) as a self-management strategy.
CDC (US), 2017: Removed GET from recommendations. Recommends pacing and energy management.
Dutch Health Council, 2018: Does not recommend GET. Supports pacing approaches.
Australia: Currently has no national ME/CFS guideline from NHMRC, though emerging clinical practice aligns with international consensus.
Why Did the Evidence Change?
This isn’t about ideology or patient pressure—it’s about scientific rigor. Three key factors drove the change:
1. Better understanding of ME/CFS pathophysiology
Research has shown that ME/CFS involves measurable abnormalities in cellular energy metabolism, immune function, and autonomic nervous system regulation. The ‘deconditioning’ theory that underpinned GET has been disproven. Two-day cardiopulmonary exercise testing shows that people with ME/CFS have reduced oxygen consumption and impaired energy production on the second day of testing—a pattern not seen in deconditioning.
2. Recognition that diagnostic criteria matter
The PACE trial used the Oxford criteria, which only require 6 months of disabling fatigue—they don’t require post-exertional malaise. This means the study likely included people with fatigue from other causes (like depression) who might respond differently to exercise than people with true ME/CFS. Modern criteria (IOM 2015, NICE 2021) require PEM as a mandatory feature, which defines a more homogeneous patient population.
3. Evidence quality standards improved
The medical community has become more sophisticated about evaluating research quality. We now recognize that subjective outcomes in unblinded trials are inherently vulnerable to bias. When you look only at objective measures—like actual activity levels, employment status, and physical capacity—the claimed benefits of GET disappear.
Resources for Patients and Healthcare Professionals
Australian Resources
Emerge Australia
- Website: emerge.org.au
- Telehealth support line: 1800 865 321
- ‘Stop. Rest. Pace.’ guide: emerge.org.au/stop-rest-pace-2/
- ME/CFS Pacing App: Free iOS/Android app with personalised energy management
ME/CFS Australia
- Pacing guidance: mecfs.org.au/resources/pacing
Queensland Health
NDIS Support
People with ME/CFS seeking NDIS support should be aware that functional assessments by occupational therapists are typically required. It’s important to document functional limitations, post-exertional malaise patterns, and note that current international guidelines recommend against GET. The ICD-10 classification for ME/CFS is G93.31 (neurological).
International Resources
#MEAction
- Comprehensive pacing guides (multiple languages): meaction.net/pacing-and-management-guides/
Workwell Foundation
- Heart rate monitoring factsheet: workwellfoundation.org/resources
CDC (US Centers for Disease Control)
- Management information: cdc.gov/me-cfs/management/
CFS Self-Help
- Activity logs and worksheets: cfsselfhelp.org/library
For Healthcare Professionals
- US ME/CFS Clinician Coalition: mecfscliniciancoalition.org
- Emerge Australia Health Professionals section: emerge.org.au/health-professionals/
- #MEAction Clinician’s Guide: meaction.net/pacing-and-management-guides
The Bottom Line
The shift from GET to pacing represents evidence-based medicine working as it should. When research was rigorously re-analysed, and patient experiences were properly documented, the evidence changed, and so did the recommendations.
For people with ME/CFS, this means:
- Pacing is safe and supported by moderate-quality evidence
- Fixed incremental exercise programs (GET) are not recommended
- You control your activity level based on your symptoms—this isn’t ‘giving in’ to illness, it’s respecting your body’s physiological limits
- Heart rate monitoring provides objective feedback to help implement pacing
While the evidence for pacing isn’t perfect—we need better quality trials with objective outcomes and standardised protocols—it has a crucial advantage: it doesn’t make people worse. In a condition where the wrong intervention can trigger months of severe disability, safety must come first.
The controversy around GET and the PACE trial serves as an important reminder that medical evidence must be continually questioned and refined. When we find that our understanding was wrong, we need the courage to change course—even when it means acknowledging that the treatments we’ve been recommending may have been causing harm.
For healthcare professionals, this means listening to patients when they report that an intervention is making them worse, requiring post-exertional malaise as a diagnostic criterion for ME/CFS, and recommending energy management strategies that help patients stay within their functional limits rather than pushing them to exceed those limits.
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