Introduction:
Why pacing matters in conditions with post‑exertional symptom exacerbation
‘Pacing’, or ‘energy management’, is a structured approach to regulating one’s physical, cognitive, and emotional activities to remain within limits imposed by chronic illnesses such as fibromyalgia, cancer, ME/CFS, and Long COVID [1,2]. Pacing ostensibly prevents post‑exertional symptom exacerbation, notably post‑exertional malaise (PEM), the worsening of fatigue, pain, cognitive dysfunction, and other symptoms following even modest activity. Across the literature, pacing is heterogeneously described as strategies that include activity planning, routine‑setting, pre‑emptive rest, breaking tasks into smaller components, monitoring energy fluctuations, and intentionally avoiding activity “push‑crash” cycles that commonly drive clinical deterioration [3]. In addition to heterogenous implementation, evidence of efficacy is also varied [3–9]. In this article, we will focus on ME/CFS and Long COVID as use case examples.
Historically, pacing emerged as an energy management method encouraging individuals to do as much as they can within their limits, rather than pushing through symptoms or following externally prescribed exercise. The central principle is that of the “energy envelope” [1], which asks individuals to identify the threshold at which activity begins to provoke symptoms and then remain inside that envelope as consistently as possible.
While definitions vary across clinicians, researchers, and patient groups, a consistent theme in both our systematic review and the scoping review is that pacing is individualised and requires ongoing adjustment as symptoms fluctuate [3,7]. Importantly, pacing is now the only management strategy recommended by the 2021 NICE guidelines for ME/CFS [10], underscoring its centrality in clinical care despite the concerning lack of evidence for efficacy. As Long COVID research evolved, pacing increasingly became recognised as a pragmatic, do no harm approach for a condition characterised by varied symptomology, unpredictable recovery patterns, and vulnerability to overexertion [8,11].
Source: Sanal-Hayes NEM, Hayes LD, Mclaughlin M, Sculthorpe NF (2026) Pacing and energy management with digital tools for conditions with chronic fatigue: What we know so far in ME/CFS and Long COVID. PLOS Digit Health 5(7): e0001586. https://doi.org/10.1371/journal.pdig.0001586 https://journals.plos.org/digitalhealth/article?id=10.1371/journal.pdig.0001586 (Full text)