ABSTRACT
OBJECTIVE: 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. RESEARCH DESIGN AND METHODS: 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. RESULTS: 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<0.001). CONCLUSIONS: Morning repeated sprint exercise conducted in postprandial state consistent with the protective effect of higher cortisol levels resulted in a lesser reduction in plasma glucose (PG) levels compared to the evening one. This highlights the potential influence of exercise timing on glycemic responses and cortisol secretion in the management of T1D.
