The impact of time-restricted eating in adults with obstructive sleep apnoea

Randomised controlled trial (pilot trial) comparing the effectiveness of Time Restricted Eating (TRE) in conjunction with Continuous Positive Airway Pressure treatment (CPAP+TRE) versus CPAP treatment alone (CPAP usual care). Implementation over 12 weeks with 1 week for baseline measures. CPAP + TRE: TRE is a dietary approach that involves limiting food intake to a specific window of time each day. It's a form of intermittent fasting where the focus is on when you eat, rather than what you eat. TRE restricts calorie intake within a defined period, allowing the body to fast for the remaining hours of the day. Patients will use CPAP for 12 weeks set up in person by a sleep scientist at a hospital clinic. Participants will be instructed by a research assistant to limit food intake to a 10 hours window for a minimum of 5 days per week, with no food consumption beyond 8pm. Water, zero calorie drinks, and prescribed medications will be allowed outside of the TRE window. Adherence for TRE is expected to be 70% to allow for lifestyle flexibility. CPAP adherence is monitored through data download from the CPAP machine itself, which tracks usage hours, mask leaks, and the pressure setting. CPAP (usual care): Patients will use CPAP set up in person by a sleep scientist at a hospital clinic for 12 weeks. Participants in this arm will be instructed by a research assistant to eat ad libitum with no restrictions on timing and frequency. All participants will attend 3 visits and undertake multiple assessments relating to sleep, cardiovascular health, and medical information. Measures with include a venous blood draw by a physician. Each participant will be asked to complete a 3-consecutive day meal timing diary at baseline, week 2, week 7, and week 12, recording the clock time of the first and last meal each day. Diary may be hard copy or via SMS as per patient preference. Adherence to TRE in the intervention group will be calculated as the number of days with a <10-h eating window/7 days of the week, expressed as a percentage. Weekly SMS reminders will be sent to participants in both groups to encourage CPAP adherence and diary logging. A food and drink diary will also be completed by all participants for 3 days (including 1 weekend day) prior to the study, during week 2 and week 7 of the intervention, and during the final week of the study to estimate daily caloric intake.