Description of intervention(s) / exposure

The pilot randomised controlled trial is a 3-arm trial of 6 months duration and 6 month follow-up. One arm pacing, another pacing plus conventional physical activity and the third pacing plus active video gaming. The pacing only arm is considered the active control, as so many people with ME/CFS already 'pace' their activities, the research team was advised by the Stakeholder Advisory Group to include pacing as the control situation.

Prior to randomisation, participants will be screened for eligibility and will participate in either a maximal effort 2 day testing protocol or a submaximal effort protocol. A submaximal effort protocol has been included as an option as community feedback indicated unwillingness from some people due to the potential symptom flare-up with the maximal protocol.

Effort testing on a bicycle ergometer is required to accurately determine the heart rate and ratings of perceived exertion (RPE) at ventilatory threshold (or 10% below the VT) for each participant. This 10% below VT has been posited as a preferred limit to stay below to avoid symptom flare-up and will be employed in this study for all three arms.

The two day maximal effort testing protocol is a smaller study running concurrently and is looking to confirm the differing physiological responses demonstrated by people with ME/CFS during repeat exercise testing when compared to healthy controls, due to post-exertional malaise. The comparison to control is not part of this study.

2 Day maximal effort test:

On two consecutive days (at the same time of day), a subjective questionnaire regarding fatigue status will be completed. Following this, 10 minutes rest while wearing HR monitor. The incremental exercise test progresses from very light to maximal exercise over a period of 8-12 minutes. The test starts with a 5 minute, 40 W warm up, during which rate of heart rate increase is assessed. Following this 5 minutes, the test increases using a ramp protocol, with increases of 5 watts every 20 seconds (so 15watts/min on average). The test finishes when the participant reaches volitional exhaustion, so when they feel they have done all that they can.

Submaximal effort test:

On one occasion, wearing a gas analysis machine and on a cycle ergometer starting at a work rate of 25 watts and increasing by 15 Watts each minute until a heart rate of 85% of age predicted maximum is achieved (208-[0.7xage]). The test will be terminated prior to this point if participants reach voluntary exhaustion, an RPE of 19, RER of greater then 1.15 or a plateau in HR or VO2 with increasing work rate.

Recommended exercise intensity will be limited to a HR corresponding to 10% below measured ventilatory threshold (VT) or in the case that VT is not adequately detected in the exercise test then below 70% of age predicted HR max.

There will be at least 4 weeks between effort testing and commencement of protocol and 2 weeks stable at pre-test pattern of symptoms/activity.

Arm 1 is considered the active control and involves teaching the participants pacing strategies to manage activities of daily living. Pacing strategies are a commonly used and typically acceptable strategy people with ME/CFS use to manage their available energy and avoid symptom aggravation. Pacing involves reflection and understanding of available energy on any given day and organisation of activities to avoid symptom flare up and provide adequate time for rest. This group will also be provided with a heart rate monitor to assist with the pacing strategy i.e. staying in acceptable heart rate zone as determined by their effort testing at baseline. There will be no instruction to increase physical activity levels in this group – and they will be encouraged not to commence any physical activity program for the 6 month period.

Arm 2 will involve a symptom-contingent pacing protocol to increase physical activity levels using a conventional non-screen-based activity of their choice (e.g. hand pedal exercise, thera-band exercise program, walking, swimming, stationary bicycle etc).

Arm 3 will involve a symptom-contingent pacing protocol to increase physical activity levels using active video gaming.

Pacing to increase physical activity Protocol

Swapping screen time with the active gaming will be recommended. If no or minimal screen time then participants will be encouraged to swap out another activities that require low cognitive or physical load. The active video gaming and conventional physical activity is intended to be additional to existing physical activities.

Encourage the exergaming or conventional activity to be conducted on those days that the participants considers there to be adequate energy to do all ADLs usual for that person etc. Do not exceed energy envelope. Encourage participants to also consider cognitive activities as potentially draining – so consider swapping them onto non-intervention days if necessary.

Every second day at the most exergaming or physical activity. Participants in the exergaming arm will be provided with a XBox Kinect and will be instructed how to play dance or sporing games some of which can be played seated/reclining. A trained research assistant will visit the participants in their homes to set up the console. It is expected the initial visit will take approximately 1.5 hours to set up the equipment and train the participant how to use the console.

The participants will be required to keep their heart rate and RPE below the stipulated level for all activities, and for the physical activity sessions. If a physical activity session exceeds the RPE (even though the HR may be in the acceptable zone) this would not be considered as symptom stable – and an additional week at the same intervention level will be required complying to the individualised maximum heart rate and RPE or lower.

Based on self-reported amount of activity from symptom history questionnaire and self-reported tendency (boom/bust or avoid) then baseline amount of exergaming/physical activity (PA) will be negotiated.

Pacing protocol will be tiered in 3 levels: light tolerance equals able to participate in light activity for at least 5 minutes (but less than 10 minutes), starting at 2 minutes of PA/session progressing by 30secs-1min/session each fortnight; moderate tolerance equals able to be active for between 10-15 minutes at a light intensity with minimal or no flare up of symptoms, starting at 5min/session PA and progressing by 1-2min/session/fortnight; and high tolerance equals able to be active for 15 or more minutes at a light intensity with minimal or no flare up of symptoms, starting at 10min/session PA and progressing by 2-4 min/session/fortnight. An accredited exercise physiologist (EP) will triage/educate/monitor the programmes. The EP research assistant will call 1xweek for 3 months and 1/fortnight for 3 months. Participants can slow, regress, plateau or cease PA at any time. All participants will fill in adherence diaries.