The time of day of exercise and its impact on subsequent night sleep duration, quality, and glucose control in type 1 diabetes

Introduction: Approximately 400,000 people are diagnosed with Type 1 diabetes mellitus (T1DM) in the UK and 32,828 in Scotland. There is currently no prevention or cure for T1DM, therefore blood glucose management and insulin replacement therapy are vital; without this T1DM will be fatal. People with T1DM are predisposed to poor sleep quality because of behavioural and physiological aspects of diabetes. This study aims to investigate the influence of the time of moderate intensity exercise on subsequent night sleep quality, duration, and glucose control in people with T1DM. Methods: Eight adult participants with T1DM were observed over 3-weeks which consisted of 1 control week and 2 intervention weeks. Blood glucose and sleep quality were measured throughout. Six 50-minute bouts of moderate intensity exercise, at a target heart rate of 64-72% of heart rate max, were completed. Three during a morning exercise week, in a fasted state before breakfast (7am–9am), and three during an evening exercise week, before the evening meal (5pm–7pm). The order of these weeks were randomised. Post intervention interviews were conducted to collect qualitative data on participant’s perceptions of sleep quality, diabetes management, exercise, physical activity and lifestyle. Results: Participants reported good or improved sleep and glucose control following both conditions. Every participant highlighted issues getting to sleep or disruptions to sleep caused by characteristics of their T1DM. There was a significant increase in daytime sleepiness following nights where a high glucose event occurred. Blood glucose during morning exercise was significantly higher than in evening exercise. Conclusion: No differences were identified in sleep quality and duration following exercise at different times of day. People with T1DM experience disruptions to their sleep and increased daytime sleepiness due blood glucose events and management.