Investigating the impact of time-of-day on glycaemia in response to postprandial supramaximal sprints in adults with type 1 diabetes

This study explores the impact of postprandial exercise timing (morning vs. evening) on glycaemia in individuals with type 1 diabetes (T1D) during short all-out sprints on a cycle ergometer. Ten healthy physically sedentary males (n=7) and females (n=3) volunteers with type 1 diabetes, aged 22.8 ± 2.8 years with a diabetes duration of 9.7 ± 5.5 years and A1C levels of 8.6 ± 1.2%, underwent comprehensive screening and assessment of their physical health and fitness status prior to study participation, under the guidance of a physician. Each participant underwent two postprandial exercise sessions on separate days: one in the morning at 8 AM and one in the evening at 8 PM, both conducted 60 minutes after a standardized meal. Morning exercise showed a less pronounced reduction in plasma glucose (PG) levels compared to evening sessions (-2.01 ± 1.24 mmol/L vs. -3.56 ± 1.6 mmol/L, P=0.03). Additionally, higher cortisol levels were observed in the morning vs. evening (128.59 ± 34 ng/ml vs. 67.79±26 ng/ml, P