‘Stepping up’ exercise for type 2 diabetes: a stepped care approach to lifestyle therapy

This is a multi-site study conducted at The University of Queensland (primary site) and The University of Sydney (secondary site). The study is a randomised controlled trial employing Stepped Care intervention vs a Comparator. In a Stepped Care intervention, participants who do not meet a pre-determined therapeutic target are 'stepped up' to the next level of intervention. Participants who meet the pre-determined therapeutic targets maintain that level of intervention. Stepped Care: All participants in the Stepped Care group start on a ‘low burden/low time commitment’ exercise prescription (150 minutes of home-based moderate-vigorous intensity aerobic exercise of their preferred choice per week (e.g. walking, treadmill, cycling, swimming- including community group-based or gymnasium based facilities if preferred) plus 2 days a week of home based resistance training-i.e the minimum physical activity guidelines for health). Those who meet these therapeutic targets (reductions of at least 0.4% in HbA1c and or a 3% weight loss) will continue at the prescription that has elicited a response- i.e., they will maintain that exercise prescription from the end of that particular step through to the 6 month follow up period. ‘Non-responders’ will be ‘stepped up’ to higher levels of exercise prescriptions. The second step involves 300 min of home-based moderate-vigorous aerobic exercise per week plus 2 days of home based resistance training. Those who meet these therapeutic targets (reductions of at least 0.4% in HbA1c and or a 3% weight loss) will continue at the prescription in this step as above while those who still do not meet these targets will be ‘stepped up’ again. The third and final step 3 will be the same as step 2, but will also include High Intensity Interval Training (HIIT). The HIIT protocol will consist of: warm-up for 5 min and at 60% of maximal heart rate (HRmax) followed by 4 x 4 min intervals at 85-95% HRmax interspersed with 3 min ‘recovery’ periods at 60% HRmax, then a 5 min cool down, 3 days a week, with one session a week supervised by an Exercise Specialist. Sessions will be generally conducted one-on-one with a maximum of 3 participants training at one time. All supervised sessions will be recorded on a clinical resource form and all home-based sessions will be recorded in an exercise log. Participants will be given a heart rate monitor and taught how to monitor the intensity of their exercise sessions using heart rates and ratings of perceived exertion (RPE). All supervised exercise will be conducted on a treadmill, unless orthopaedic limitation exists in which a cycle ergometer will be used. Home-based exercise depend on the access to exercise equipment and preferences of the individual participant. Accordingly, Step 3 will equal 105 min of HIIT, plus 195 min of moderate-vigorous home-based aerobic exercise, plus 2 resistance based sessions each week. At each step, the frequency and duration of exercise sessions will be determined by the participant at the exercise prescription session (i.e. the participant will decide how they will meet the relevant Step’s exercise prescription targets). All participants in the Stepped Care group also receive dietary advice to follow a Mediterranean Diet Eating Pattern. Support: All exercise prescription sessions will be with an Exercise Specialist. Individuals will have a total of 8 contacts with an Exercise Specialist: i) 2 x 30 minute face-to-face consultations in weeks 1 and 5 of a 8 week step, involving personalised exercise prescription and instruction on how to use an activity diary and activity monitor and ii) fortnightly contact with the Exercise Specialist. The resistance training program will be supported by provision of an exercise booklet illustrating and instructing the following exercises: Sit to stand (bodyweight), overhead press (using water bottles/cans of food as weight), squat (bodyweight), chest press/push up (body weight), lunge (bodyweight), arm curl (using water bottles/cans of food as weight), hip extension (body weight), triceps dips (body weight), calf raise (body weight), prone bridge (body weight). Progressions of these exercises will be facilitated by the exercise specialist. In week 1, all participants will receive a 45 min individualised consultation with an Accredited Practicing Dietitian (APD). For the remainder of the intervention period (i.e. for either 8 wks, 16 wks or 24 wks depending on Step at which participants respond) monthly group-based 30 min check-ins, led by an accredited health profession via Zoom, will be offered to all participants to support adherence to the Mediterranean dietary pattern. All dietary information and contact with the APD will be consistent across participants. Adherence to the home-based exercise programs will be monitored by: wearable activity monitor, an exercise diary and self-report to the exercise specialist at the face to face and telephone contact sessions. Adherence to the diet will be monitored by questionnaires at each assessment timepoint and by self report at the monthly group-based diet check-ins. Outcome Assessment Time frames: Stepped Care participants will have measures at baseline, week 8; and then potentially at week 16; and potentially at week 24, pending their ‘response’. Stepped Care participants will have a follow up assessment 6 months after their post-assessment for the Step that they complete the study on.