American Health & Medical Research Association
Pain, fatigue & chronic conditions

Pacing can mean two opposite things, so ask which one you’re getting

Why pain programs and ME/CFS care use one word for opposite strategies, what research shows for each, and what heart-rate monitors can and can't tell you.

By the Health Research USA editorial team

Published Last updated October 2026

Written from the sources listed below; links checked October 2026. It touches on medicines, doses or health conditions and has not yet been reviewed by a licensed clinician, so use it to prepare for a conversation with yours. How we research and review

Sources25, listed below Reading time16 minutes
On this page
  1. One Word, Two Traditions
  2. Pacing for Chronic Pain: Popular, Lightly Tested
  3. Pacing in ME/CFS and Long COVID: What Agencies Say
  4. What the Pacing Trials Show
  5. Heart-Rate Monitors: A Tool Without a Number
  6. Questions That Reveal Which Pacing You're Being Offered
  7. When to Get Help
  8. The Bottom Line on Pacing

At a pain clinic, you’re given a schedule. Walk for eight minutes, then rest for five, whether today feels good or bad. Next week, ten minutes. At a clinic that treats myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), the advice sounds similar and works the other way: find out where your limit is, stay under it, and don’t spend a good day catching up.

Both are called pacing. In chronic pain programs, pacing usually means working to a preset quota so that activity can climb steadily. In ME/CFS, it usually means keeping activity inside a personal limit to avoid post-exertional malaise (PEM), a crash that tends to arrive a day or two after effort. One approach aims to build up. The other aims to hold steady.

Mixing them up muddies the research, too. A 2012 meta-analysis of 41 studies found that people with chronic pain who said they paced themselves reported better mood, but also more pain and disability. Pacing is popular and widely recommended, and in both traditions it is surprisingly thinly tested.

One word, two traditions

A 2013 narrative review in the Clinical Journal of Pain, led from St Joseph’s Health Care London in Ontario, Canada, traced activity pacing to two main sources: operant behavioral treatment for pain, and energy conservation. The traditions share some elements, the authors wrote, but differ in significant conceptual and practical ways, which has caused confusion. They offered only a provisional definition, and noted that pacing can be aimed at two opposite problems: doing too little, or doing too much.

Operant pacing: the plan decides

A systematic review published in September 2026, led from a National Health Service pain service in Greater Manchester, England, defines operant pacing as doing activities by quota, set as an amount, a time or a goal, rather than according to how bad symptoms are. The target is a pattern that the same research group calls overdoing-underdoing cycling: doing too much on a good day, paying for it, resting for days and losing ground. Common ingredients include planning ahead, alternating activity with rest, and switching between tasks or body positions.

Many programs also build in progression, a gradual raising of the quota. The method is partly a guard against avoidance, the slow slide into doing less and less, which the same group lists alongside overdoing as a behavior pacing tries to change. The 2026 review deliberately left out energy-envelope pacing and other symptom-led approaches, treating them as different interventions.

Energy-envelope pacing: the limit decides

In ME/CFS, pacing starts from the opposite premise. The Centers for Disease Control and Prevention (CDC), which also calls it activity management, puts the purpose plainly: “The goal of pacing is to learn to balance activity and rest to avoid PEM flare-ups.” People work out their individual limits for mental and physical activity, then plan their days within them. Some patients and doctors, CDC notes, call this staying inside the energy envelope.

CDC’s provider toolkit on managing PEM extends the budget to cognitive and emotional effort as well as physical. Its example: someone might find that 30 minutes of reading is fine while an hour straight triggers PEM, which puts that person’s reading limit at 30 minutes. CDC also describes the trap pacing is meant to prevent. On a good day, people are tempted to push, which can bring on a crash, and the cycle repeats once they start to recover. In this site’s shorthand, that is boom and bust.

The two methods agree on the problem: swinging between overdoing it and collapsing. They disagree on direction. Operant pacing usually plans for activity to rise. Envelope pacing lets activity rise, if at all, only as tolerance allows; CDC’s toolkit says any recommendation for more activity should take the person’s energy limits into account.

So pacing is not one technique. It is at least two, built on opposite logic.

The 2013 review’s authors concluded that there was little empirical evidence on whether pacing works as a chronic pain treatment.

The 2012 meta-analysis, from the University of Queensland’s occupational therapy division in Australia, pooled 41 studies reporting correlations between how people with chronic pain approached activity and how well they were functioning. Avoiding activity was consistently linked to more pain, worse psychological functioning and more disability. Pushing on until pain became severe was tied to poorer outcomes too. Pacing was the puzzle: “Pacing was generally linked to better psychological functioning but more pain and disability.”

These were correlations, not trials. The authors offered two explanations without being able to pick one: pacing may not help unless it is used to build activity gradually, or people with more pain and disability may simply be more inclined to pace. Either way, the finding does not show that pacing causes pain.

Trials tell a similarly modest story. A 2019 review in the American Journal of Occupational Therapy, the American Occupational Therapy Association’s journal, included only randomized trials of pacing taught as a skill and found seven. Pacing did not reduce pain severity or change psychological traits. It did ease joint stiffness, reduce how much fatigue interfered with daily life, and make day-to-day activity less erratic.

The September 2026 review of operant programs found nine studies of 10 interventions, with 873 participants, ranging from 2 to 11 sessions. Results generally pointed toward better function, with mixed findings for pain and fatigue. The reviewers could only count which way results pointed, and they rated their confidence in the evidence as very low.

Part of the problem is measurement. In 2025 the same group reported that research on pacing has been hampered by the lack of a validated scale, and tested a 12-item questionnaire in 347 patients attending health services in England, covering adjustment, planning, consistency and progression of activity.

On the library’s evidence scale, pacing for chronic pain is insufficient: not disproven, but too loosely defined to have been tested cleanly. Pacing also turns up inside cognitive behavioral therapy for pain, which our article on psychological approaches to pain weighs.

Pacing in ME/CFS and long COVID: what agencies say

CDC says ME/CFS has no cure and no approved treatment, and it puts pacing at the center of its management advice. Keeping activity and symptom diaries may help people find their limits, CDC says, especially early in the illness; our fatigue-duration explainer sets out a simple version of that log. The National Institute of Neurological Disorders and Stroke (NINDS), in a page reviewed in May 2026, likewise says people with ME/CFS can pace themselves by carefully balancing activity and rest.

CDC’s toolkit is direct about why pacing is not surrender. It says that in the past, patients were told to be more active without any precautions about PEM. It says minimizing PEM can stabilize or improve pain, sleep, fatigue, thinking and other symptoms, and that pacing may considerably improve quality of life and even increase function. It also warns that inactivity can lead to muscle deconditioning. That corrects the second common belief, that pacing simply means giving up.

CDC’s examples of easier ways to do chores, such as sitting while doing laundry, taking frequent breaks and splitting big tasks into steps, are energy-conservation techniques, which a coming article in this series covers in detail.

For long COVID, CDC’s clinical guidance, updated in March 2026, doesn’t use the word pacing. It says patients may take specific steps to mitigate PEM, and recommends patient diaries and calendars to track symptoms. A 2025 consensus statement from the American Academy of Physical Medicine and Rehabilitation (AAPM&R) calls energy-conservation strategies a critical consideration and says activity must be tailored to each patient’s current tolerance.

What the pacing trials show

The PACE trial’s pacing arm

The best-known test of a pacing therapy was PACE, a British trial reported in The Lancet in 2011. Its 641 patients, recruited at six clinics, were diagnosed using the Oxford criteria, an older case definition. On top of specialist medical care, groups received adaptive pacing therapy, graded exercise or cognitive behavioral therapy, or nothing extra. At 52 weeks, adaptive pacing made no significant difference compared with specialist care alone: fatigue scores were 0.7 points lower and physical function scores 3.4 points lower, both within chance. The authors judged it not an effective addition. The trial report itself noted that patient organizations favored pacing.

That result is not the last word. Outcomes were self-reported by participants who knew which treatment they were getting, and PACE tested one pacing protocol in one population. A Cochrane review that compared exercise with adaptive pacing, using a single trial, rated that evidence low certainty and cautioned that patients diagnosed by other criteria may respond differently. The broader fight over PACE is laid out in our ME/CFS article.

What pooled trials found

A 2022 meta-analysis from the Kirby Institute at the University of New South Wales in Sydney pooled 14 randomized trials. Compared with no treatment or usual care, pacing interventions reduced fatigue by a moderate amount, eased psychological distress and depression, and improved physical function scores by about 7 points on average.

The twist is in what those programs contained. The improvement was larger in programs that encouraged people to gradually step up their physical and mental activity, an approach the authors’ keywords call pacing up. In other words, some of what trials have labeled pacing for chronic fatigue syndrome included gradual increases, and those programs did best. England’s National Institute for Health and Care Excellence now advises against increases that follow fixed increments, according to a 2022 summary of its guideline. That is a difference in definitions, not a contradiction between studies.

A 2023 scoping review, written by researchers at the University of the West of Scotland with co-authors from the patient group Long COVID Scotland and the clinician network Physios for ME, cast a wider net. Of 17 studies, only three were randomized trials. Eleven reported benefits, four no effect and two worse results than in comparison groups, and quality ranged from poor to fair. The authors concluded the evidence was not yet strong enough to guide treatment for ME/CFS or long COVID.

What the energy-envelope studies add

The energy-envelope idea was developed over 15 years by a team at DePaul University in Chicago, whose own review reported quality-of-life gains. Their cross-sectional work adds nuance. In a 2017 study, overexertion seemed to cost most among people with more energy available to begin with. A 2013 analysis found one group of patients who stayed closer to their envelope and used more adaptive coping, yet were the most impaired of all. Staying inside the envelope is not a guarantee.

Teenagers

A 2024 UK trial of 314 adolescents aged 11 to 17 with ME/CFS compared an online cognitive behavioral program with activity management delivered by video call. At six months, physical function scores were 8.2 points higher in the online program group. By 12 months the difference was no longer clear, both groups had kept improving, and a pre-defined measure of worsening was met by about a quarter of each group. The same NINDS page adds that young people with ME/CFS recover, partly or fully, more often than adults do.

A long COVID trial built around pacing

A major US test of pacing is part of RECOVER-ENERGIZE, a trial funded by the National Institutes of Health. Its pacing arm enrolled adults with long COVID whose PEM had lasted at least 12 weeks. Participants had 12 weekly sessions of about 30 minutes, planned mainly as video calls, with local pacing coaches trained for the study, learning to recognize PEM, spot triggers, set limits, log activity and conserve energy, while wearing an activity tracker that watched heart rate and step counts. The design paper gives no threshold values, and says activity was expected to stabilize rather than increase. The comparison group got usual care, basic information about PEM and a weekly support call.

The main outcome is change in how often PEM occurs, how severe it is and how long it lasts, measured by questionnaire at 12 weeks. The design paper, a June 2026 preprint not yet peer reviewed, says no clear consensus exists on how best to treat PEM. Its pacing arm enrolled 300 people and finished in November 2025; the registry entry shows results as posted. A peer-reviewed report had not appeared when this article was written.

The library’s verdict on pacing for ME/CFS and long COVID, for now: insufficient evidence, largely because studies test such different things under one name.

Heart-rate monitors: a tool without a number

CDC says some patients find that wearing a heart rate monitor helps them track how hard their body is working and prevent PEM. Its toolkit adds that some people use monitors to stay below the anaerobic threshold, the point where muscles lean heavily on energy production that doesn’t use oxygen, and that studies have found a lowered threshold in people with ME/CFS. Neither CDC source gives a heart-rate number or a formula.

The research is thin. A 2023 international online survey drew 488 people with ME/CFS through ME websites and social media; most were women aged 35 to 50 who had been ill for more than five years, and they reported using more than 100 kinds of monitor. Respondents said monitoring reduced their overall severity and made PEM shorter and milder. The respondents chose to take part and reported their own results, and several authors belong to Physios for ME or a heart-rate pacing group. The authors themselves noted that only one study had examined heart-rate monitoring for pacing, even though several guidelines recommend it.

A 2026 study from Newcastle University in England followed 19 adults with post-COVID fatigue for three months, logging 2,182 days with a wearable tracker and a symptom app. On days when people chose more active pacing goals, same-day fatigue was lower, but the next-day effects were not significant. People picked their goals based on how they already felt, which the authors said limits any conclusion, and they called for randomized trials.

So the belief that a monitor tells you your safe limit runs ahead of the evidence. Whether a heart-rate target makes sense at all, especially alongside a heart condition or medicines you take, is a question for the prescriber or cardiologist.

Questions that reveal which pacing you’re being offered

These are our own, built from the differences above. No answer is wrong in itself, but the answers should fit your condition.

  1. What tells me to stop: the clock, a quota, or my symptoms?
  2. Is my activity supposed to rise, and on what schedule? Ask who decides when to step up, and on what basis.
  3. What do I do on a good day? Operant plans say stick to the quota. Envelope plans say don’t bank extra.
  4. Does the plan count thinking, emotional strain and noise, or only physical activity?
  5. Which group was this approach tested in? Chronic pain, ME/CFS and long COVID are different populations.
  6. What counts as success here? More activity, fewer crashes and steadier days are three different goals.
  7. If a device or number is involved, where did the number come from?

When to get help

  • Crashes that start 12 to 48 hours after ordinary activity and last days. That timing is how CDC describes PEM, and it is worth a diagnostic evaluation rather than months of solo trial and error.
  • Pacing has shrunk life to very little, or symptoms keep worsening despite it. A clinician can look again at the diagnosis and for other contributors; AAPM&R lists heart, lung, hormonal, nutritional, metabolic and chronic infectious causes worth considering when activity tolerance is low.
  • New symptoms of any kind. They deserve their own evaluation, since a pacing plan was built around the old ones.
  • Low mood or hopelessness. Long illness and a narrowing life can wear anyone down. If you have thoughts of suicide, call or text 988 to reach the 988 Suicide & Crisis Lifeline, which is free, confidential and open around the clock. If you are in immediate danger, call 911.

The bottom line on pacing

The word pacing, on its own, tells you almost nothing. In a chronic pain program it usually means sticking to a plan that builds activity on schedule; in ME/CFS care it usually means staying under a limit to prevent crashes. The evidence for both is weaker than their popularity suggests, and CDC, the agency that mentions heart-rate monitors, offers no number to aim for.

Before starting any pacing plan, ask what sets the limit and which direction the plan is meant to go. Those two answers tell you which kind you are being offered, and whether it matches what happens to you after effort.

Sources

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  3. Centers for Disease Control and Prevention. “IOM 2015 Diagnostic Criteria (ME/CFS, for health care providers; last reviewed May 10, 2024).” cdc.gov
  4. Centers for Disease Control and Prevention. “Long COVID Clinical Guidance (last updated March 9, 2026).” cdc.gov
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