Intervention
Incremental physical activity for CFS/ME includes the establishment of a patient-specific baseline of achievable and sustainable exercise or physical activity, followed by slow increments in the duration of physical activity.
Incremental physical activity aims to gradually increase the patient’s ability to undertake physical activity and reduce their feeling of fatigue. How it works is not understood but it may prevent/ reverse the secondary physical deconditioning and exercise intolerance related to prolonged (relative) inactivity.
There are different models for implementation that show likely benefit. A shared element in randomised clinical trials (RCTs) showing benefit is that the activity or exercise is slowly increased over time. Incremental physical activity differs from adaptive pacing therapy (APT) by encouraging the participant to extend their physical activity beyond their baseline in a programmed stepwise progression rather than staying well within (~70%) of their perceived energy expenditure envelope.
Indication
People with chronic fatigue syndrome (CFS)/ myalgic encephalomyelitis (ME).*
Incremental physical activity has also been shown to improve muscle strength, cardiovascular endurance and symptoms in a wide variety of conditions that have chronic fatigue as a symptom, such as heart disease, cancer, chronic obstructive pulmonary disease and post-viral fatigue.
*Note: There have been many definitions (and multiple names) for the condition, given that diagnosis is essentially based on symptoms and the exclusion of other illnesses, with no current internationally agreed definition. Most of the clinical trials used an older, more inclusive definition. More recent narrower definitions will exclude many patients with a chronic fatigue problem. Hence incremental physical activity is likely to be helpful for the broader group but applicability is less clear for the more recent narrowly defined groups. The US Centers for Disease Control and Prevention website outlines the history of case definitions and criteria.
Precautions/Adverse effects
Unaccustomed activity can produce or exacerbate many CFS/ME symptoms. A mild and transient increase in symptoms is explained as a normal response to an increase in physical activity; however, a more severe or sustained exacerbation suggests the activity was excessive. Patients may feel shamed or blamed if it is implied they are too fearful of activity or too fearful of exacerbating their symptoms of post-exertional malaise (PEM). Onset of PEM may be delayed for up to 3 days after exercise.
Surveys by patient groups of their members have suggested that incremental physical activity may be harmful to some people with CFS/ME and advocate against such programs. This is a valid concern, but may be due to inappropriately planned or progressed exercise programs, possibly undertaken independently or under supervision from a person without appropriate experience, or subgroups within the spectrum of CFS/ME who are more vulnerable to more severe PEM. Implementation needs to be very sensitive to these concerns and be aware that many patients and carers will be very aware of the strong advocacy specifically against such programs. Trust and acknowledgement of these concerns, with appropriate caution is likely to be crucial.
Availability
Incremental physical activity should be supervised by a physiotherapist or accredited exercise physiologist, preferably with specific experience and training in working with people with CFS/ME. Costs vary significantly depending on the type of exercise. In some cases, health insurance may cover some costs.
The PACE trial has produced a comprehensive graded exercise therapy (GET) therapist manual (and a manual for patients), which can be downloaded free of charge by going to the PACE trial website and selecting the relevant manuals from the trial information section.
Description
Graded exercise therapy (GET) is a program of incremental physical activity used in the largest of the seven RCTs to date. It is delivered in three phases over several sessions (e.g., 15 sessions in the PACE trial – see Table 1).
After assessment of the patient’s current physical capacity, and mutual negotiation of meaningful and functional physical goals, a baseline of physical activity is agreed upon and commenced, at a manageable low level of intensity.
Any activity that can be incrementally increased in terms of duration, intensity, frequency is appropriate, including walking, swimming, and the use of exercise machines. These activities can be alternated, noting that a change in activity may require adjustment to the duration, intensity, frequency of the activity.
Physical activity can be increased by:
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Increments of duration: duration of physical activity is increased slowly (10–20%), once every 1–2 weeks provided any PEM has been only mild and transient (see Precautions). (note other RCTs showing benefit from exercise used much smaller/slower increments)
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Increasing intensity: intensity is increased by encouraging the patient to do an activity faster e.g., speed up the pace of their walk or swim.
However, increase in intensity is done with care and is likely to be done in stages. It can be useful to build up the intensity by adding in shorter bursts of higher intensity activity to the program; for example, starting with 1 minute of fast walking interspersed with 2 minutes of normal pace.
If increased symptoms occur after an increment, the patient is encouraged to stick at the current level until symptoms reduce, and then increase afterwards. However, activity is mutually reviewed on a regular basis, and plans may be adjusted depending on the patient’s general health and symptoms.
Tips and challenges
Although GET has been extensively tested in clinical trials, it remains controversial within some support groups.
The PACE trial highlighted a number of clinically important considerations, including:
- Individualising treatments and a flexible physical activity prescription
- Encouraging variety and maintaining physical activity levels
- Encouraging physical activity and strategies for planning physical activity
- The importance of not exceeding the planned level of physical activity
- The importance of relying on HR, rather than a sense of effort
- The importance of achieving a healthy balance of physical activity.
Compliance
Most trials have found few dropped out of GET, and no more than other treatments. Increased long-term rest is not recommended and can lead to further deconditioning. Exercise and physical activity considered a safe intervention with numerous health benefits, including physical and mental health. However, participating in an uncontrolled manner can increase symptoms temporarily.
Rate of Progression
It may be tempting for the patient and therapist to increase the rate of physical activity progression after initial success as one might in other exercise interventions. However, this may be the trigger for the poor outcomes widely reported among the CFS/ME community.
Communication
CFS/ME patients often have a history of feeling poorly heard, feeling blamed for their symptoms as being primarily mental health or activity avoidance, or unsuccessful trials of other interventions. A trusting collaborative approach is likely to be crucial.
Mental Health Disorders
More than two-thirds of patients with CFS/ME in the trials meet diagnostic criteria for mental health disorders such as anxiety disorders, dysthymia, or depression. Whether this is due to the CFS/ME or not, it should be treated so that the patient can better manage their CFS/ME. Many therapies have been tried in CFS/ME but only CBT and incremental exercise therapy appear to produce meaningful benefit. However, neither of these treatments are “curative”, but can help patients improve their function and quality of life.
Grading
Moderate. (We are moderately confident in this research evidence. Future research is likely to refine/ change the recommendation. This has been downgraded from ‘Strong’ due to concerns about definition/ inclusion criteria and implementation concerns/ experience)