Résumé
Background and Aims: Exercise is part of type 1 diabetes (T1D) management based on its cardiovascular and metabolic benefits. However, despite the use of real‐time continuous glucose monitoring (CGM) glycaemia during exercise remains difficult to control. We assessed trends in glucose, lactate and ketone profiles during anaerobic and aerobic exercise in people with T1D and explored whether patterns could be identified that could guide insulin dosing.Methods: Twenty‐one men with T1D (age 29 years [28‐38], BMI 24.4 kg/m2 [22.3‐24.9], HbA1c 7.2% [6.7‐7.8]) completed a symptom‐limited maximal cardiopulmonary exercise test (CPET) and a 60‐minute aerobic exercise (AEX) at 60% VO2peak on an ergometer bicycle. Subjects consumed a standardised Ensure® breakfast before exercise without administering an insulin bolus.Results: During CPET, glucose levels increased, peaking at 331mg/dL [257‐392] 1‐3h after exercise and reaching a nadir 6h after exercise at 176mg/dL [118‐217] and lactate levels peaked to 12.5mmol/L. During AEX, glucose levels also increased, peaking at 305mg/dL [245‐336] 80 minutes after exercise and reaching a nadir 6h after exercise at 211mg/dL [116‐222]. Lactate levels rose quickly to a maximum of 4.3mmol/L [2.7‐6.7] after 10 minutes, indicating that some participants performed a mixed aerobic anaerobic test. Ketone levels were low in both tests (median ≤0.2mmol/L).Conclusions: High intensity exercise resulted in hyperglycaemia coinciding with an increase in lactate levels. In the context of using only basal and no bolus insulin, no events of late hypoglycaemia or ketosis were recorded during or after the aerobic and the anaerobic test, indicating safety under current circumstances.