A novel digital solution to educate and empower young people with Type 1 Diabetes on how to exercise safely.

Participants will be trialling a newly-refined mobile App for physical activity, (first developed for project ACTRN12619001414101), to provide guidance on carbohydrate and insulin dosing for young people with type 1 diabetes. Participants will be involved in the study for 12 weeks. In the first four weeks (run-in period), participants will be given time to become familiar with the activity-monitoring watch and continuous glucose monitoring system that they will be required to wear for the remainder of the study period. During the next four weeks (pre-intervention period), participants will continue to wear the continuous glucose monitor and activity-monitoring watch during periods of physical activity, while following their usual diabetes management. At the end of this 4-week period, participants will have the App installed on their smartphone at an in-clinic visit, under the guidance of an endocrinologist and/or research assistant/officer. For the last 4-week period (intervention period), participants will continue their regular exercise/physical activity, using advice provided by the App to assist with their diabetes management. During the 4-week pre-intervention and 4-week intervention periods, CGM readings uploaded to Dexcom Clarity will allow us to assess rates of hypoglycaemia during these periods, including during times of exercise which will be captured by the activity-monitoring watch. Participants will be advised to change their sensor every 10 days, and participants will be supplied with enough sensors for the duration of the study. The App has been co-designed with the target population for this study, with further refinements made based on initial feedback received from participants during project ACTRN12619001414101. The content of the App is split into two main sections/features, with participants required to enter basic demographics the first time they use the App. The main feature of the App begins with the “Exercise Now” button. This prompts users to either “Add an activity”, or “Use one of your favourites”. If “Add an activity” is selected, the user is prompted to select Walk, Run, Swim, Cycle, Team Sports, Strength Training, or Other. The user is then asked to select from one of three ‘emojis’ to indicate the intensity of their activity, select their duration of exercise (up to 30 minutes, 31 to 45 minutes or 45 to 60 minutes), the time of their last insulin bolus, and their current blood glucose (BGL) reading. Based on the user selections, the App will then provide carbohydrate and insulin advice for that activity. This advice provided is split into three brief sections, displayed on the one screen as follows: ‘Pre-exercise advice’ suggests an amount of carbohydrates to take before starting the activity, e.g., “Have 15g Carbs before you start exercise.” ‘Insulin advice’ suggests adjustments to insulin, e.g., “If you are using an insulin pump, reduce your basal rate by 50% until the end of exercise.” ‘During exercise advice’ suggests an amount of carbohydrates to take during the activity and reminds participants to check their blood glucose level, e.g., “Have 12g Carbs at the 30 minute point of exercise if your glucose level is less than 7 mmol/l.” If the exercise duration entered by the participant is longer than 30 minutes, the App will also notify them to check their blood glucose level at the 30 minute mark of exercise. Users can also ‘save’ the activity as a favourite to quickly use again in the future, while the activity log/calendar function also allows users to view past activities and advice. The other main feature of the App is the “More Info” tab, which allows users to access more generalised exercise advice without having to log a specific activity. This section is split into four sections: - Hypo (hypoglycaemia) treatment: Suggestions for hypo treatment. - Food Guide: Definitions of low and high GI foods and their effect on glucose levels. - Pre-exercise advice: Generalised meal and insulin advice for 1 to 3 hours prior to exercise. - Post-exercise advice: Advice on managing glucose levels immediately after exercise and in the following hours (e.g., overnight). The advice used in the App is based on guidelines from the International Society for Pediatric and Adolescent Diabetes, American Diabetes Association, and the Lancet: Diabetes and Endocrinology. Participants will be asked to exercise at least twice a week using the App. Google Analytics in conjunction with RedCap will provide information about participant adherence to this (i.e. how frequently the App is being used), how long users are interacting with the App, and time spent on specific features/pages of the App. Questionnaires relating to participants' physical activity, diabetes management, anxiety, hypoglycaemia fear and hypoglycaemia awareness will be administered at four-week intervals via RedCap. Participant diaries (to record events such as sick days and new medications) will be provided as paper copies, with data manually uploaded to RedCap by the study team. At the end of the study, participants will also complete a user mobile application rating scale (uMARS) and may complete a semi-structured interview with a trained member of our research staff. Participants will be invited to participate in the interviews until investigators are satisfied that theme saturation is reached. Parents of participants under 18 years of age will also complete a single-item questionnaire about their confidence in their child's ability to exercise safely.