Trends of glucose, lactate and ketones during anaerobic and aerobic exercise in subjects with type 1 diabetes: The ACTION‐1 Study

International audienceBackground: Exercise is part of type 1 diabetes (T1D) management due to its cardiovascular and metabolic benefits. However, despite using continuous glucose monitoring, many patients are reluctant to exercise because of fear for hypoglycaemia.Aims: We assessed trends in glucose, lactate and ketones during anaerobic and aerobic exercise in people with T1D and compared incremental area under the curve (AUC) between both exercises.Methods: Twenty-one men with T1D (median [IQR]: age 29 years [28-38], BMI 24.4 kg/m2 [22.3-24.9], HbA1c 7.2% [6.7-7.8]), completed a cardiopulmonary exercise test (CPET) and a 60-minute aerobic exercise (AEX) at 60% VO2 peak on an ergometer bicycle within a 6-week period. Subjects consumed a standardised breakfast (6 kcal/kg, 20.2g CHO/100ml) before exercise without pre-meal insulin and basal insulin for pump users.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]. Lactate levels peaked at 6.0mmol/L [5.0-6.6] (max 12.5mmol/L). During AEX, glucose levels also increased, peaking at 305mg/dL [245-336] 80 min after exercise and reaching a nadir 6h after exercise at 211mg/dL [116-222]. Lactate levels rose quickly to a median of 4.3mmol/L [2.7-6.7] after 10 min. Ketone levels were low during both tests (median ≤0.2mmol/L). Lactate, but not glucose or ketone AUC, was significantly higher in CPET compared to AEX (p=0.04).Conclusions: Omitting pre-meal insulin and also basal insulin in pump users, did prevent hypoglycaemia but induced hyperglycaemia due to a too high carbohydrate ingestion. No ketosis was recorded during or after the exercises