Pacing, conventional physical activity and active video gaming to increase physical activity levels for adults with myalgic encephalomyelitis/chronic fatigue syndrome: a pilot feasibility study
-
Brett Tarca
,
Kade Davison
,
Ashleigh E. Smith
Abstract
Objectives
People living with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) may face unique barriers to physical activity. Active video games may overcome these barriers and increase physical activity. The primary aim of this pilot study was to determine the feasibility and acceptability of active video games to increase physical activity levels of people with ME/CFS.
Methods
A mixed method design was employed. Adults living with ME/CFS were randomised to a six-month intervention of (1) pacing, (2) pacing and conventional physical activity, or (3) pacing and active video gaming. Feasibility and acceptability were determined through semi-structured interviews. Health-related outcomes (e.g., physical activity, blood samples, quality of life, and functioning) were also collected.
Results
Fifteen people were assigned an intervention group with 12 completing. Three themes were identified from post-intervention interviews (1) positivity led to overall acceptability, (2) flexibility enabled participant autonomy, and (3) knowledge was gained about the self. No changes were seen in physical activity levels. An active video gaming intervention is acceptable but not feasible for people living with ME/CFS.
Conclusions
Taken together, results suggest that physical activity can be managed safely by some people living with ME/CFS. Trial registration ACTRN12616000285459.
Introduction
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex chronic condition characterised by fatigue persisting longer than six months, and post-exertional malaise (PEM) that is not alleviated by rest [1]. Global prevalence is unclear with estimates ranging from 0.89 to 1.14 % [2]. Following mental or physical exertion, people living with ME/CFS may experience an exacerbation of symptoms (i.e. PEM) varying in severity (minimal impact to mental and/or physical collapse) lasting from days to weeks [3]. As a result, people living with ME/CFS are often unable to undertake employment, social or recreational activities [4]. Consequently, this cohort can experience increased levels of sedentary behaviour which can further exacerbate physical deconditioning, cognitive symptoms and reduced quality of life [5].
Participation in physical activity has the potential to induce favourable health benefits including reduced cardiometabolic disease risk and enhanced physical function, mental well-being and health-related quality of life [6]. Despite this, physical activity-based (e.g. exercise therapy) interventions are not well understood in this population, with the effectiveness, safety, optimal intervention design, and method of delivery yet to be properly elucidated. A review of eight physical activity-based interventions concluded that whilst definitive conclusions were difficult to draw, it was likely that physical activity had a positive effect on fatigue experienced by adults living with ME/CFS compared to usual care or passive therapies [7]. The authors also reported that evidence regarding potential adverse effects are uncertain [7]. As a result of symptom aggravation, limited evidence, and potential fear/avoidance of activity, people living with ME/CFS may avoid participation and consequently, report lower physical activity levels compared with healthy controls [5], [8].
Pacing is an approach that can be employed to manage symptom fluctuations while participating in physical activity. Pacing encourages people to recognise their own envelope of available physical and mental capacity before symptom exacerbation, and to effectively pace themselves to use their available capacity to maximum effect and then rest before reaching their individual point of exhaustion [9]. Pacing draws on elements of self-determination theory by allowing participants to self-regulate their activity within their perceived boundaries, promoting intrinsic motivation and sense of control, both of which are important in ME/CFS management [10]. Gentle paced physical activity has been associated with improvements in physical function, fatigue management, and psychological well-being co-morbidity development/progression in some individuals [7]. A single study employing a symptom contingent protocol (i.e., a pacing protocol where increases in exercise/activity were advised when patients felt they were coping with their current activity level) for people with ME/CFS reported improvements in physiological indices (e.g., blood pressure), work capacity, depression, mental fatigue, perceived exertion and cognitive performance [11]. Patient groups have reported pacing to be the most effective, safe, acceptable, and preferred form of activity management for people with ME/CFS [12]. Further interventional data are required to explore the effectiveness of pacing when employed in physical activity-based programs.
Studies employing physical activity-based interventions for ME/CFS have typically employed conventional exercises (e.g., walking, cycling, strength training) [11], [13], [14]. Active video gaming (AVG) offers a potentially feasible alternative approach to increase physical activity participation for people with ME/CFS. Active video gaming can be broadly summarised as any video game that requires participant trunk and limb movements for game play [15]. Games can be played at home, standing or sitting, and for short periods (e.g., 1–2 min). Emerging evidence supports the use of active video games (AVG) in adult clinical populations to promote physical activity, with reported benefits in physical function and illness management [16], [17], [18]. Furthermore, AVG offers potential to mitigate mentally passive sedentary behaviour (e.g., low engagement activities such as watching television), promoting mentally active sedentary behaviour (cognitively stimulating activity such as light computer tasks) which may offer cognitive improvement and psychosocial benefit [19]. However, despite this emerging potential, the feasibility and utility of AVG have not yet been explored in individuals with ME/CFS.
It is theorised that one way physical activity plays a role in the management of chronic health conditions (e.g., improved quality of life, reduced morbidity and mortality [20], [21]) is via an anti-inflammatory action and reduction of allostatic load. Allostatic load refers to the ‘wear and tear’ the body experiences when ‘being forced to adapt to adverse psychosocial or physical situations, and it represents either the presence of too much stress or the inefficient operation of the stress hormone response system’ [22]. Higher allostatic load is associated with increased mortality [23] and some studies have reported people living with ME/CFS may have higher allostatic loads compared with healthy controls [24]. There is evidence to suggest that higher physical activity levels are associated with lower allostatic load [25], [26], however the extent of the relationship is still unclear for people living with ME/CFS with no longitudinal data available [27].
Recent management recommendations for the diagnosis and on-going management of ME/CFS include (1) energy management practices (e.g., pacing) and (2) flexible, symptom-paced physical activity programs (if requested) [28], and given no studies have investigated AVG in this population, a feasibility and acceptability study was deemed necessary.
Research aims
The primary aim of this pilot study was to investigate the feasibility and acceptability of pacing and AVG to increase the physical activity levels of adults with ME/CFS. The secondary aims of this study were to (1) explore the preliminary effectiveness of pacing and AVG to pacing and conventional physical activity to pacing alone to increase the physical activity levels of adults with ME/CFS, and (2) explore the relationship between allostatic load and physical activity in people with ME/CFS. The summary of this article is presented in Figure 1.
Graphical representation of this study. Key points: (1) the study explored an innovative, home-based approach to physical activity tailored to the unique needs and limitations of people with ME/CFS by combining a symptom-contingent pacing protocol with active video gaming. (2) Support from exercise professionals assisted participants in understanding their physical thresholds and ability to self-manage their physical activity participation. (3) Physical activity can be safely managed when implementing a symptom-contingent pacing approach in this cohort and could be employed as a strategy to increase activity participation so that people living with ME/CFS can enjoy the health benefits of an active lifestyle. Figure created with BioRender.
Materials and methods
A detailed description of the study protocol has been previously published, so an abridged version is presented below [29].
Protocol development
A 6-month stakeholder advisory process, involving representatives from the regional ME/CFS society, a rheumatologist and a general physician with expert clinical experience caring for people with ME/CFS, two adults living with ME/CFS, and the research team, was conducted to develop the study protocol.
Study design
A mixed-method design was employed comprising a three-armed randomized controlled pilot study. The three groups were as follows: (1) pacing, (2) pacing and conventional physical activity, and (3) pacing and AVG. All health-related outcomes were completed at three time points: baseline, six-month post baseline (end of intervention), and 12-month post baseline. Additionally, accelerometer, inclinometer and heart rate data were collected during week six, 12 and 18 of the intervention. The protocol was approved by the University of South Australia Human Research Ethics Committee (Protocol No. 0000035299) with registration to the Australia New Zealand Clinical Trials Registry (ACTRN12616000285459).
Study population
A convenience sample of adults aged from 18 to 65 years living in South Australia who had: (1) a diagnosis of ME/CFS by a general practitioner or medical specialist, (2) general practitioner clearance, (3) ability to complete exercise testing, (4) not currently playing active video games, (5) score low or moderate risk on the Australian Adult Pre-Exercise Screening System Tool [30], (6) self-report less than 150 min of moderate intensity physical activity each week, and (7) a game console compatible television in their home (internet not required) and be willing to play AVGs were recruited. The protocol was amended (with approval) to remove the requirement for participants to self-report a diagnosis based on a commonly accepted diagnostic criteria, this was due to the unexpectedly low number who were able to report the criteria used for their diagnosis. Participants were recruited via local community support groups, fliers, social media and the clinical trials facility website. All participants provided written consent and general practitioner clearance to participate. The study aimed to recruit 30 participants.
ME/CFS diagnosis
The administration of the Canadian Consensus Criteria [31] to participants at the 6-month follow up was an amendment to the protocol and allowed characterisation of the cohort against a common diagnostic criteria [29].
Testing venue
Baseline, six-month and 12-month testing was completed at the university clinical trials facility. This facility contained a clinical exercise physiology lab used specially for CPET assessments at the University of South Australia. If in-person attendance was not possible, survey assessments were mailed to participants. Physical activity and sedentary behaviour assessment devices at weeks four, eight, 12 and 16 were mailed out.
Effort testing (baseline only)
Effort testing sessions, either two-day maximal effort or a submaximal protocol (participant choice) on a stationary cycle protocol. A sub-maximal effort protocol was included as an option as community feedback indicated unwillingness from some people due to the potential symptom flare-up predicted with the maximal protocol. The 2-day maximal effort protocol employed an incremental protocol to volitional exhaustion according to previously published protocol [32]. This protocol involved attending testing facility two consecutive days at the same time and participating in the same testing protocol on a cycle ergometer wearing a gas analysis mask. The test starts with a 5-min, 40-W warm-up. Following this, the test ramps incrementally, with increases of 5-W every 20-s (i.e., 15-W per minute) until the participant reaches volitional exhaustion. The sub-maximal alternative involved a single visit to the testing facility. This protocol started with a resistance of 25 W, increasing by 15 W every minute until a heart rate of 85 % of age predicted maximum was achieved (208 − [0.7 × age]). Participants wore a chest band heart rate monitor (RS800CX, Polar Electro Oy) throughout effort testing to identify heart rate and RPE at ventilatory threshold and subsequently guide individual participant pacing thresholds. Ventilatory threshold was determined manually by the V-slope method which plots carbon dioxide output against oxygen uptake to identify the point at which carbon dioxide begins to increase disproportionately relative to oxygen uptake during incremental exercise. Once this threshold is determined, heart rate at 10 % below the ventilatory threshold was established. This 10 % below limit has been postulated as a preferred upper threshold to mitigate symptom flare up for people with ME/CFS [33], and was employed as the pacing threshold across all three groups.
Intervention groups
After baseline assessment, participants were randomised (computer-generated random number sequence) into either pacing only, pacing plus conventional physical activity, or pacing plus AVG. Block randomisation was modified (with human research ethics approval) in response to low recruitment numbers to ensure adequate numbers in the conventional exercise and AVG groups to allow meaningful exploration of acceptability and safety of the exercise protocols. The intervention duration was six months with weekly phone support from research assistants. All participants were provided heart rate monitors (Polar RS400, Polar, Kempele, Finland) and a prescribed heart rate threshold. All participants received an Xbox Kinect (Microsoft Corp, Redmond, WA) for their participation upon completion of the study.
Pacing group
Participants were educated about the concept of pacing and their prescribed heart rate and rating of perceived exertion (RPE) thresholds established from effort testing. There was no instruction to increase physical activity levels.
Pacing plus conventional physical activity
Participants were educated about the concept of pacing and prescribed a participant-controlled symptom-contingent physical activity program by an accredited exercise physiologist. For the purpose of this study, conventional physical activities were considered standard exercise activities such as combinations of walking, elastic band resistance exercises and/or cycling (stationary or road) based on participant preference.
Pacing plus AVG
The AVG group were educated about the concept of pacing and provided with an Xbox Kinect (Microsoft, Redmond, WA). Participants were prescribed a program involving dance and sport games.
Programs for both the AVG and conventional physical activity group were tailored to the individual based on answers provided in the Symptom History Questionnaire which allowed for allocation into an activity tolerance tier (light activity tolerance, moderate activity tolerance or, high activity tolerance). Progressions were added fortnightly if the participant reported a stable heart rate and RPE over the preceding two-week period. Full description of the prescription categories can be found in the published protocol [29].
Feasibility and acceptability outcomes
Exit interviews
Post intervention exit interviews were conducted (face to face or phone) to explore the feasibility and acceptability of the intervention and study protocol for all participants. Question topics about the intervention included barriers, support provided from the research team, and how the activity (if appropriate) fit in with participants’ lifestyles. Question topics about the assessments included participants’ thoughts on the frequency, burden and type of assessments. Interviews were audio-recorded.
Adverse events
Adverse event data were collected by the research assistants during the weekly support phone call and defined as ‘any clinical change, disease, or disorder experienced by the participant during their participation in the trial, whether or not considered related to the intervention studied in the trial’. Serious adverse events were defined as outcomes involving death, threat to life, hospitalisation, disability and any other important medical condition that required medical or surgical intervention to prevent one of the aforementioned outcomes. All other adverse events were classified as non-serious. Participants reported if the events were intervention related.
Adherence
All three groups were provided a six-month pen and paper diary to document adherence to prescribed heart rate and RPE limits (i.e. the pacing protocol). The AVG and conventional physical activity groups additionally documented daily minutes of physical activity completed.
Secondary outcomes (health-related outcomes)
All health-related outcomes are described in Table 1. A data collection schedule can be seen in Supplementary File 1.
Description of health-related outcomes.
| Outcome | Procedure |
| Device-based measured activity | Physical activity was captured via a GENEActiv (ActivInsights, Cambs, UK) tri-axial accelerometer, with data reported as minutes per day of low, moderate, and vigorous physical activity. Sedentary behaviour was assessed using activPAL (PAL Technologies Ltd, Glasgow, UK) inclinometers fixed to the front upper thigh with medical taping, and data were reported as minutes spent lying, standing and seated per day. Both devices were worn for seven continuous days. In the event that participants did not wear for 7-days, at least 4-days (including one weekend day) of recorded wear time was required to be considered a valid file. |
| Self-reported time use | The Multimedia Activity Recall for Children and Adults (MARCA) [34] is a computer-delivered time-use instrument that captures detailed recording of time-use behaviours over a 24-h period. This was completed through a phone call from a research team member on four separate days, within the same seven-day period that the accelerometer and inclinometer were worn and included at least one weekend day. Outcomes of interest included time spent (mins) of dedicated physical activity (e.g. exercise), screen time (e.g. TV, computer, mobile device use), sleep and rest, occupational activities, household tasks, self-care, transport, social/leisure activities and education/study. |
| Anthropometric data | Height was captured using an ECOMED SECA 284 (Ecomed Trading, Australia) stadiometer. Weight was captured using TANITA BC-418 (Tanita, Japan) bioelectrical impedance analysis scales. Waist girth was taken at the narrowest point between the superior iliac crest and the 10ths rib and captured using a Lufkin W606PM (Cooper Industries, Lexington, Surrey, Canada) tape measure. Participants were measured wearing light clothing and no shoes. Feet were placed together for all measurements with arms folded across chest in the form of an X. |
| Physiological data | Blood pressure was captured using an Omron HEM7120 Blood Pressure monitor with the participant seated upright. Body temperature was captured via an electronic thermometer to assess any acute inflammatory response (fever). |
| Biochemistry | Venous blood samples were collected at baseline and six-months post baseline by an on-site phlebotomist with participants being fasted for at least 8 h. Blood plasma samples were analysed by an external laboratory (state-wide pathology provider for the public health sector [Clinpath Pathology]) for lipid profiles (total cholesterol, HDL and triglycerides). Inhouse university laboratory ELISA analysis was conducted for noradrenaline and adrenaline (IBL ELISA) and insulin (Insulin ELISE) and Konelab analysis for glucose and C-reactive protein data. |
| Allostatic load | Allostatic load was determined through anthropometric, physiological and pathology data collected. Each index was classified as healthy zone (coded 0) or the unhealthy zone (coded 1). Diagnostic cut-points were used for establishing healthy/unhealthy zone (see below) however in the absence of clinically acceptable cut-points, quintiles were established with the upper 25th percentile deemed the unhealthy zone (coded 1). Prescribed medications for blood pressure, glucose and cholesterol were considered as indicative of an ‘unhealthy’ status for the corresponding health condition and thus assigned the value one. The diagnostic cut points were as follows:
|
| Physical capacity | The Karnofsky Scale [35] was used as a self-report measure to capture current capacity of the participant to perform daily activities. Scores range from 0 to 100 with higher score indicative of higher self-perceived capacity to complete activities. It was administered weekly for the first 3-months (phone call with research assistant) of the intervention to monitor participant capacity levels and identify any potential adverse events in response to the intervention. |
| Physical and mental fatigue | The Chalder Fatigue Scale [36] was used as a self-report measure to capture physical and mental fatigue. Total score ranges between 0 and 33 with higher score indicative of higher self-perceived fatigue experience. |
| Sleepiness | The Berlin Sleep Score instrument is typically used as a self-report measure to assess the risk (i.e. low to high) of having sleep-disordered breathing (i.e. sleep apnoea) [37]. The present study utilised the responses to Category 2 to reflect the level of daytime sleepiness. |
| Quality of life | The Short-Form 36 Questionnaire [38] was used as a self-report measure to assess overall health and quality of life. It produces scores between 0 and 100 in eight domains of health, with higher score indicative of higher self-perceived quality of health and life in the respective domain. |
| Dietary intake | Dietary intake, including total energy, macronutrient and food group consumption, was recorded using three-day weighed food records. Participants were instructed to record all food, drink and supplements consumed over three consecutive days including one weekend day and two weekdays. |
| Cognitive function | The Cognitive Failure Questionnaire [39] was used as a self-report measure to assess failures in perception, memory and motor functioning. Total score ranges between 0 and 100 with higher score indicative of more frequent self-perceived cognitive failures. The Cambridge Neuropsychological Test Automated Battery [40] (CANTAB) was used to objectively assess executive function, short-term memory and processing speed. |
Sociodemographic and symptom history
Questionnaires developed for this project captured participant particulars including, age, gender, education, employment status, income, medical history, all symptoms related to ME/CFS in addition to the relationship between symptoms and activity (used to assist in the activity prescription).
Data processing
Exit interview transcripts were transcribed verbatim by a professional transcription company. Physical activity data were downloaded through GENEActiv PC Software Version 3.2 (ActivInsights, Cambs, UK) with subsequent processing through MATLAB R2019a (MathWorks, Inc., Natick, MA, USA). Sedentary behavior data were downloaded through activPAL Process and Presentation Software Version 7.2.38 (PAL Technologies Ltd, Glasgow, UK) and processed using activPAL Event Analysis Version 0.5.3.14 (PAL Technologies Ltd, Glasgow, UK) to quantify the time spent in sitting, lying (excluding normal sleeping time [manually trimmed]) and standing. All anthropometric, physiological, blood and questionnaire data were entered into Microsoft Excel Version 2016 (Microsoft, Redmond, WA) workbooks (.xlsx). Data from 3-day weighed food records were entered into FoodWorks (Xyris Software, Australia, 2003). All CANTAB outcome measures were downloaded into Microsoft Excel Version 2016. To calculate cognitive composite scores for Executive Function, Short-Term Memory and Processing Speed, relevant CANTAB outcome variable scores were converted to z-scores and averaged. The CANTAB outcome variables included in each composite score are reported in Supplementary File 2 and were informed by the Cattell-Horn-Carroll-Miyake classification of cognitive factors and Cambridge Cognition [41], [42].
Data analysis
Qualitative interview data underwent inductive thematic analysis according to the six steps outlined in Braun and Clarke [43]. An independent qualitative expert conducted the analysis and coded the interview transcriptions entered into NVivo 12 (QSR International, UK). Consultation with the principal researcher and initial notes taken during the interviews contributed to the development of preliminary themes. Themes were finalised by the qualitative expert upon revision with the main author.
Feasibility of recruitment was considered by calculating the percentage of participants that were assigned an intervention against the number who expressed interest and, the recruitment rate (recruitment duration in weeks/number of participants). Adverse event data were converted to a rate of adverse events per person, per week. Narrative synthesis was employed to describe adherence to the respective interventions from research assistant field notes and adherence logs. Descriptive statistics described all anthropometric, physiological, blood, questionnaire, allostatic load, MARCA, diet and CANTAB data. Physical activity and sedentary behaviour data were expressed as mean values and 95 % confidence intervals. Regression analysis will be used to explore preliminary evidence of a relationship between allostatic load and physical activity and categorical questionnaire data analysed using chi-square analysis. All quantitative data analysis was conducted using SPSS Statistical Software Version 25.0 (IBM Corp. Armonk, NY).
Results
Recruitment, allocation and retention
Recruitment was open between February 2017 and June 2018. Of the 48 people who expressed interest and were approached, 20 underwent initial exercise testing (15 maximal assessment/five sub-maximal assessment). Fifteen participants (mean age(SD) 36.5(12.2) years and 73 % female) were allocated to an intervention group (Figure 2). Ten participants completed maximal assessments with results suggestive of post-exertional malaise (power output reduction >9.7 % [32]) with power output reductions at ventilatory threshold ranging from 12 to 57 % on day two testing compared to day one. Reasons for missing data across week six, 12 and 18 physical activity and sedentary behaviour assessment timepoints included participant declined (n=7), participant did not wear (or removed devices) (n=6) or contact from participant was lost (n=14). One participant missed the six-month follow-up assessment due to hospitalisation (for reasons not related to this study) but remained enrolled and completed 12-month follow up.
Participant flow.
Participant sociodemographic, anthropometric, physiological and pathology markers
General participant demographic details for each group are presented in Table 2. Eleven (73 %) participants reported a general practitioner made the diagnosis of ME/CFS with the remaining diagnoses made by an immunologist (n=2), paediatric specialist and rheumatologist.
Participant demographic information.
| All (n=15), mean (SD) | AVG + pacing (n=7), mean (SD) | Conventional physical activity + pacing (n=6), mean (SD) | Pacing only (n=2), mean (SD) | |
|---|---|---|---|---|
| Age, years | 36.5 (12.2) | 40.7 (11.9) | 27.3 (5) | 49.7 (7.7) |
| Female, % | 73 | 43 | 100 | 100 |
| ME/CFS duration, years | 10.7 (7.7) | 10.9 (6.3) | 8.9 (6.9) | 15.4 (11.6) |
| Currently employed, n yes | 8 | 3 | 3 | 2 |
| Average hours paid employment, h | 20.4 (11.2) | 23.3 (13.6) | 15.8 (6) | 23 (15) |
| Complete volunteer work, n yes | 4 | 1 | 2 | 1 |
| Average hours volunteering, h | 6.5 (2.5) | 6 (0) | 9 (1) | 3 (0) |
| Education level, n yes | ||||
| High school | 3 | 2 | 1 | – |
| Post-secondary diploma/certificate | 8 | 3 | 3 | 2 |
| Bachelor’s degree | 4 | 2 | 2 | – |
| Receiving treatment for ME/CFS, n yes | 8 | 6 | 1 | 1 |
On visual inspection, the groups appeared well matched for body mass index, waist girth, blood pressure and blood data at baseline however allostatic load was heterogenous across the cohort (0–6 factors present) (Supplementary File 3).
ME/CFS diagnosis
At baseline, two participants reported being diagnosed using the Canadian Consensus Criteria [31], and 11 did not know the diagnostic method used. From the seven participants who completed the Canadian Consensus Criteria [31] at 6 months, two met the criteria for ME/CFS. From these two, one reported at baseline that the criteria were used in their diagnosis whilst the other was unsure. Three participants were unable to complete due to personal scheduling issues whilst one refused to complete due to self-reported limited cognition tolerance. Supplementary Table 4 details the objective maximal effort testing data, the diagnostic criteria reported at baseline and classification based on the Canadian Consensus Criteria.
Feasibility and acceptability
Recruitment rate
From those who expressed interest, 31 % were allocated an intervention. Recruitment rate was one new participant per 4.5 recruitment weeks.
Exit interviews
Eight participants (62 % female) participated in an exit interview, one belonged to the pacing group, three from the conventional physical activity group plus pacing, and five from the AVG plus pacing group. Three key themes were identified, ‘Positivity led to overall acceptability’, ‘Flexibility enabled participant autonomy’, and ‘Knowledge was gained about the self’. Summary of themes including exemplar quotes can be seen in Table 3.
Summary of exit interview themes with exemplar quotes.
| Theme | Description | Exemplar quotes |
| Positivity led to overall acceptability | Study protocol generally accepted with support from staff leading to positive experiences throughout study. Active video gaming concept acceptable, however, participants reported technical and implementation issues resulting in low feasibility. | “I didn’t find it difficult at all, in fact it was really good to be doing and keeping active…” – Female, Conventional Physical Activity + Pacing “I found it hard with the video gaming to do such a short time… It might have only been five minutes, actually gaming, but the whole thing took about twenty minutes, by the time it loads…” – Female, AVG + Pacing “…I think you guys [research staff] have been great and that’s one of the things that I’ve really valued about participating in this study, is getting that support…” Male, AVG + Pacing |
| Flexibility enabled participant autonomy | Flexible study protocol ensured participants were able to adhere to study intervention, assessments and/or other requirements. Flexibility regarding the intervention was important, especially with being able to increase or decrease physical activity. For most participants, pacing provided a sense of control and/or ability to progress their exercise amount more successfully. | “Now I found [emails] a lot easier than phone calls, because… I’m not always cognitively able to speak properly and get across what I want to say, but yeah, emails was (sic) a lot easier and I could just answer them when I needed to.” – Female, AVG + Pacing “So, if I wasn’t feeling overly great, I’d just choose an easier game.” – Female, AVG + Pacing “Probably different games… maybe something with Pilates, or Yoga, or something like that… because I can do it within my house, rather than having to drive anywhere…” – Male, AVG + Pacing |
| Knowledge was gained about the self | Participants became self-aware of their own bodies and enjoyed being able to control and/or manage their symptoms. | “So, the written assessments and the iPad assessment I found really interesting because I could see, it actually explained symptoms to me that I wasn’t aware of… Then I thought, oh… that’s why I get that or yes it is, it’s in all part of the illness. So, by normalising it, it makes it easier to accept it.” – Male, AVG + Pacing “I think I just was frustrated because I was given a heart rate not to go over, but I found like you guys were spot on. I don’t know how you come up with that number, but when I was going over it I started to crash again, so yeah it was a good thing that…” – Female, Conventional Physical Activity + Pacing “I can tell when my heart rate is at 90 because I’ve done it, I can tell when I stand up that I’ve gone from 60 to 90. So I’ve become a little more in tune with my own body.” – Female, Pacing “…What I feel I’ve learnt is that pacing means… if I’ve done an hour’s work on the computer or 90 minutes I need to stop and do nothing and maybe lie down for half an hour or 45 minutes recovery. So, if I go and do 4 hours work which I’ve done in one lump I pay for it the next day. So, heart rate for me that makes no difference over that.” – Female, Pacing |
Theme 1: positivity led to overall acceptability
Most participants (n=7) interviewed found the testing protocol acceptable. The support received from study staff contributed to participants’ positive experiences. Although all participants suggested areas of the study that could be improved, minimal barriers were experienced regarding the intervention and any negative aspects reported were often related to blood tests or the two-day maximal test.
The two-day maximal test was generally accepted overall, with perceived benefits of obtaining objective proof of their illness and gaining a better understanding of personal physical limits. Select participants (n=2) would not recommend the test to future CFS patients based on the potential long-term fatigue. The written assessments were generally accepted, although some participants (n=2) suggested there could be reporting errors in the daily adherence diaries. Skin irritation (due to adhesive tape) was an issue for a few participants (n=2), but, most participants (n=6) said that the inclinometer did not interfere with their lifestyle. Certain study aspects including blood tests, the diet diary, and pacing, were considered similar to everyday life.
Intervention experiences were mostly positive, and random allocation was accepted by all. The conservative pacing process was helpful to most participants (n=7) and was least helpful to a pacing group participant with no prescribed exercise. Pacing and exercise group participants found the intervention the most helpful, as it related to their everyday exercise activities.
The most reported enjoyable study aspect was the positive support received from the research staff. All participants appreciated that they could freely ask questions, and the accommodating nature of the staff during the intervention was reported as helpful for over half of participants.
Theme 2: flexibility enabled participant autonomy
Flexibility provided by the research team throughout the entire study contributed to the overall acceptability. Testing and the intervention were successfully implemented when they fit easily into participants’ everyday lives, providing a sense of autonomy. Control was gained from the choice of exercise to combine with pacing, the freedom to reduce exercise if it was too much, and the choice around which active video game to play. Suggestions to improve the study for future CFS patients were related to flexibility, convenience, and control, and included using more digitised data collection methods and more AVG options.
Active video gaming was considered as potentially convenient for those who are not very active, for when the weather is too poor to exercise outside, and for those who use gaming software or can easily access it. The pacing with active video gaming intervention was reported by many (n=4) as not feeling like a workout, although this depended on the activity level of the game. Suggestions for improving the intervention included using different gaming software to provide more varying levels of activity, and to satisfy individual interests.
Theme 3: knowledge was gained about the self
The development of knowledge was a key aspect of the study, with many participants (n=6) either wanting to gain more knowledge about their own bodies, wanting to quantify their illness, or wanting to contribute to science and help future ME/CFS patients. The intervention provided positive aspects for all participants, such as gaining a better understanding of personal physical capabilities based on the concept of pacing and keeping their heart rate below a specified value.
Many valued the results of the two-day maximal test which provided supporting evidence for their diagnosis and a way to quantify their illness to medical professionals and government agencies, among others.
Most participants (n=7) took something from the study that will benefit them in the future, whether exercise-related or not. Participants understood and valued the concept of pacing differently, with some already doing pacing in their everyday life. Even though the selected participants did not report pacing with the heart rate goal as helpful, they still gained greater understanding about how their bodies behave from differing lengths of activity.
Adverse events
Total number of adverse events including cause and outcome, stratified by intervention group is presented Supplementary File 5. From 23 (rate of 0.05 adverse events, per person, per week) adverse events, two (both in conventional physical activity and pacing group) were classified as a serious adverse event, both resulting in hospitalisation however, both were unrelated to the study. Of the 21 non-serious adverse events, eight (rate of 0.02 adverse events, per person, per week) were deemed by the participants to be related to the study assessments/intervention including; skin irritation as a result of wearing the ActivPAL inclinometer or heart rate monitor chest strap (n=5), upper limb pain due to game play (n=1), anxiety due to the mental demand of phone assessment (n=1) and, post-exertional malaise from an increase in exercise duration (n=1). No events resulted in the withdrawal of a participant however one participant from the AVG plus pacing group ceased the game play but remained in the study.
Adherence
Nine participants returned adherence diaries with three completing the full six-month log. Two participants from the active video gaming plus pacing group (88 and 72 % adherence, respectively) and one participant from the conventional physical activity plus pacing group (95 % adherence). Six participants returned adherence logs with between 4 and 14 weeks of entries missing and three did not return the log. In total, 114 weeks of adherence data were available (63 % missing).
Secondary outcomes (health related outcomes)
Physical activity data
Device-based physical activity and sedentary behaviour data are presented in Supplementary File 6. Baseline physical activity levels (average moderate-vigorous physical activity (MVPA) min/day (mean (SD)) for the AVG plus pacing group were 53(19), conventional physical activity plus pacing group 92(17) and pacing group 50(6). Mean differences between groups at the six and 12-month follow up for MVPA and sitting time can be seen in Table 4.
Mean difference in physical activity and sedentary behaviour between groups.
| MVPAa | Sitting timea | |||
|---|---|---|---|---|
| 6-months | 12-months | 6-months | 12-months | |
| difference (CI) | difference (CI) | difference (CI) | difference (CI) | |
| CPAb/AVG | −55 (−141, 31) | −56 (−130, 18) | c | 26 (−202, 254) |
| CPAb/pacing | −3 (−196, 190) | c | c | c |
| Pacingb/AVG | −52 (−122, 18) | c | 137 (26, 248) | c |
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aAll numbers expressed in average minutes per day. bFirst named group is the reference group. cInsufficient data. AVG, active video gaming plus pacing group; CI, confidence intervals; CPA, conventional physical activity plus pacing group; MVPA, moderate-vigorous physical activity.
Physical activity and allostatic load
Graphical observation of MVPA minutes per day and total allostatic load at baseline does not suggest any relationship (Figure 3).
7-day average minutes of moderate-vigorous physical activity and total allostatic load at baseline (each dot reflects a single participant) (participants had to have completed all blood, physiological and device-based physical activity assessments to be included in this analysis).
Questionnaire data
The Karnofksy Scale, Chalders Fatigue Scale, Cognitive Failure, Berlin Sleep Score, Short-Form 36 and MARCA data are presented in Supplementary File 3.
Dietary intake and Cambridge neuropsychological test automated battery data
Baseline nutrition characteristics are presented in Supplementary File 7. One participant declined to complete the diary due to exacerbated mental burden. CANTAB data across groups and time are presented in Supplementary File 8.
Discussion
The primary aim of this pilot study was to investigate the feasibility and acceptability of AVG plus pacing to increase the physical activity levels of adults with ME/CFS. The qualitative results suggest that the concept of AVG was acceptable, considered convenient for people who aren’t typically active, and participants would potentially utilise it in future if there were more gaming options (e.g., pilates, yoga, etc.). Feasibility however, including practicality and implementation issues, was low for the specific AVG intervention employed in this study.
A challenge of any intervention is whether participants perceive it to be acceptable, and beneficial for them to engage [44]. This is particularly the case when involving a population that have previously reported fear/avoidance to participation in physical activity [5]. The participant controlled, symptom-contingent pacing approach in this intervention is in stark contrast to previously employed physical activity approaches (i.e., graded exercise therapy) [11]. Participants enjoyed the level of autonomy built into the intervention, specifically, the flexibility of being able to increase or decrease physical activity. Continued consumer and stakeholder engagement will be essential for any future iterations of the current intervention.
An additional challenge not anticipated during the planning phase was that most participants did not know the method employed for their ME/CFS diagnosis (only four participants were able to report this at baseline). The two-day cardiopulmonary exercise test has been explored as a potential assessment to provide objective data indicating the presence of post-exertional malaise (moreover ME/CFS) [45]. It is suggested that reductions in power output at ventilatory threshold >9.7 % indicate post-exertional malaise [32]. Ten of the 11 participants who were assigned an intervention exceeded this reduction. Of the seven participants who completed the Canadian Consensus [31] screening instrument at follow-up (two met the criteria), all had previously completed the maximal effort two-day test and, reported reductions in power output at ventilatory threshold >9.7 %, indicative of objective post-exertional malaise. This small group comparison suggests objective testing may be more sensitive than the commonly used Canadian Consensus [31] instrument.
The feasibility of the intervention was deemed to be low with poor recruitment and retention being major limiting factors. From an estimated 11,000 people living with ME/CFS in South Australia [46], only 15 were assigned an intervention over a 17-month period. Recruitment may have been negatively impacted by a small but vocal number of people in the ME/CFS community spreading misinformation about the study via social media and patient support groups. The motive of these individuals was not known although their messaging insisted that (1) physical activity is harmful, and (2) research funds should only be allocated to projects that directly seek to understand the pathological mechanisms and lead to an eventual cure. Although the latter point is entirely understandable, the researchers and stakeholder advisory group members believed the desire to maximise the quality of life for those already suffering from such a debilitating disease is also important, and worthy of research investment.
The extensive testing protocols and high staff input to monitor and support participants poses challenges for feasibility and implementation. The study design evolved from an extensive stakeholder and consumer consultation process to tackle important issues (barriers) including access and safety. The resulting intervention was home-based (increasing access and reducing burden to travel for supervision), deliberately conservative in exercise prescription parameters and progressions to ensure safety and acceptability and, included intensive contact with research support staff. Based on participant feedback, it is unlikely a ‘light-touch’ version, with less support from suitably qualified practitioners (exercise physiologists in this case) would be as acceptable. A recent national survey of people living with ME/CFS reported an appropriate health practitioner who understood the condition was key to them trusting and taking on physical activity advice (unpublished data). Future physical activity interventions should consider including a suitable exercise professional who is competent to work with people living with ME/CFS.
A concern for people living with ME/CFS is that physical activity may exacerbate symptoms, hence, many are reluctant to engage in physical activity [5]. Eight adverse events were related to the intervention with the majority (n=6) being related to the testing procedures and not the exercise. There were two exercise-related events, one participant experienced post-exertional malaise that was well managed with activity modification, and the other experienced upper limb pain that resulted in a cessation of the gameplay for three days before controlled resumption with no further incident. Whilst the rate of adverse events in the present study is consistent (when applying the same metric) with other clinical populations [47], [48], [49], due to the small sample size in this study, it is unclear if this rate, and the type of adverse events reflect the wider ME/CFS population. Nevertheless, the data give an indication that self-managed physical activity can be safe. When baseline physical activity levels (Supplementary File 5) were explored, surprisingly, the majority of participants (93 %) were already meeting national recommended physical activity guidelines [50]. This suggests most participants underestimated their activity levels (inclusion criteria: self-reported not meeting activity guidelines). Future studies with larger samples should explore the physical activity benefits of such interventions for the most inactive vs. active participants in the cohort.
Sampling issues should be considered when interpreting these findings. The small sample is representative of a subset of people suffering ME/CFS, those people living in the community who were well enough to be physically active, able to contemplate a physical activity intervention and to attend a university for testing procedures. People who were willing to enrol in the study may have had a certain level of skill or preference to active videogaming. A major limitation of the study was the inability to maintain contact with participants. Research staff continually made attempts however participants were often unavailable or did not respond. This impacted the ability of research staff to arrange testing sessions when scheduled, leading to missing data across all time points. Limited intervention adherence data precluded the research team from drawing more definitive conclusions regarding safety, feasibility, and acceptability of the interventions. Furthermore, the small sample size limited the ability to conduct the initial statistical analyses proposed (regression and chi-square analysis) and, necessary to evaluate the intervention’s impact on health outcomes. It is additionally important to acknowledge the daily fluctuations in fatigue when interpreting both feasibility and outcomes for interventions involving individuals living with ME/CFS. The present study did not explore within-person variability (e.g., daily changes in fatigue) which may influence physical activity engagement and behaviour [51]. This is particularly relevant as individuals may have inconsistent capacity to participate in daily tasks, including active video gaming. Consequently, the lack of change observed at the group level may in-fact mask meaningful intra-individual responses. Future studies should consider incorporating within-person assessments, such as ecological momentary assessment to track fatigue symptoms alongside activity, which has been reported as feasible in other clinical cohorts [52]. Future studies could aim to employ a less burdensome assessment protocol with increased flexibility to perform assessments in a participant’s preferred setting (e.g., home) utilising technology such as mobile applications to collect data.
Conclusions
This pilot study demonstrated the acceptability but not the feasibility of a symptom-contingent pacing monitored AVG intervention in this cohort of people living with ME/CFS. Future research should consider avenues for less resource intensive and burdensome physical activity interventions that prioritises support and safety with the need for sustainable and scalable interventions. Nevertheless, the acceptability combined with the low rate of adverse events suggests that physical activity can be managed safely by some people living with ME/CFS.
Funding source: Mason Foundation
Award Identifier / Grant number: MAS2015F053
Acknowledgments
The research team are grateful for the contribution of the stakeholder advisory group members and the participants for contributing their time and expertise.
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Research ethics: The protocol was approved by the University of South Australia Human Research Ethics Committee (Protocol No. 0000035299) with informed consent gained from all participants prior to completing any study requirements.
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Informed consent: The protocol was approved by the University of South Australia Human Research Ethics Committee (Protocol No. 0000035299) with informed consent gained from all participants prior to completing any study requirements.
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Author contributions: Study protocol and design: AS, KD, KF; Data acquisition: BT, KT; Data analysis/interpretation: BT, AS, KD, AW, KT, KF; Statistical analysis: BT, AW, KT; Supervision or mentorship: KF, AS, KD. Each author contributed important intellectual content during manuscript drafting or revision and has approved the final version. Furthermore, each author agrees to be personally accountable for the individual’s own contributions and to ensure that questions pertaining to the accuracy or integrity of any portion of the work, even one in which the author was not directly involved, are appropriately investigated, and resolved, including with documentation in the literature if appropriate.
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Use of Large Language Models, AI and Machine Learning Tools: None used.
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Conflict of interest: The authors declare no conflict of interest. Author KD is an editorial board member for Translational Exercise Biomedicine and was not involved in the editorial review or the decision to publish this article.
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Research funding: This project was funded by the Mason Foundation National Medical Program (MAS2015F053).
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Data availability: The data that support the findings of this study are available from the corresponding author, (BT), upon reasonable request.
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Supplementary Material
This article contains supplementary material (https://doi.org/10.1515/teb-2025-0017).
© 2025 the author(s), published by De Gruyter on behalf of Shangai Jiao Tong University and Guangzhou Sport University
This work is licensed under the Creative Commons Attribution 4.0 International License.
Artikel in diesem Heft
- Frontmatter
- Section: Integrated exercise physiology, biology, and pathophysiology in health and disease
- Power, cardiorespiratory fitness and physical activity in young people with cerebral palsy
- Section: Personalized and advanced exercise prescription for health and chronic diseases
- Supported exercise within transdiagnostic mental health services: a protocol paper for a two-arm hybrid effectiveness-implementation trial
- Section: Physical activity/inactivity and health across the lifespan
- Exploring the impact of short-term adherence to physical activity guidelines to improve the intrinsic capacity of older adults
- Walking sports and subjective wellbeing in older adults: a comparative study
- Section: Exercise and E-health, M-health, AI and technology
- Examining communication effectiveness in multicultural fitness programs-multivariate analyses
- Effect of a wearable-sensor-assisted multicomponent exercise program on physical fitness, cognition and quality of life in frail older adults
- Pacing, conventional physical activity and active video gaming to increase physical activity levels for adults with myalgic encephalomyelitis/chronic fatigue syndrome: a pilot feasibility study
Artikel in diesem Heft
- Frontmatter
- Section: Integrated exercise physiology, biology, and pathophysiology in health and disease
- Power, cardiorespiratory fitness and physical activity in young people with cerebral palsy
- Section: Personalized and advanced exercise prescription for health and chronic diseases
- Supported exercise within transdiagnostic mental health services: a protocol paper for a two-arm hybrid effectiveness-implementation trial
- Section: Physical activity/inactivity and health across the lifespan
- Exploring the impact of short-term adherence to physical activity guidelines to improve the intrinsic capacity of older adults
- Walking sports and subjective wellbeing in older adults: a comparative study
- Section: Exercise and E-health, M-health, AI and technology
- Examining communication effectiveness in multicultural fitness programs-multivariate analyses
- Effect of a wearable-sensor-assisted multicomponent exercise program on physical fitness, cognition and quality of life in frail older adults
- Pacing, conventional physical activity and active video gaming to increase physical activity levels for adults with myalgic encephalomyelitis/chronic fatigue syndrome: a pilot feasibility study
