Effect of combining pre‐exercise carbohydrate intake and repeated short sprints on the blood glucose response to moderate‐intensity exercise in young individuals with Type 1 diabetes

Aims To determine whether pre‐exercise ingestion of carbohydrates to maintain stable glycaemia during moderate‐intensity exercise results in excessive hyperglycaemia if combined with repeated sprints in individuals with Type 1 diabetes. Methods Eight overnight‐fasted people with Type 1 diabetes completed the following four 40‐min exercise sessions on separate days in a randomized counterbalanced order under basal insulinaemic conditions: continuous moderate‐intensity exercise at 50%V ˙ O 2peak; intermittent high‐intensity exercise (moderate‐intensity exercise interspersed with 4‐s sprints every 2 min and a final 10‐s sprint); continuous moderate‐intensity exercise with prior carbohydrate intake (~10 g per person); and intermittent high‐intensity exercise with prior carbohydrate intake. Venous blood was sampled during and 2 h after exercise to measure glucose and lactate levels. Results The difference in marginal mean time‐averaged area under the blood glucose curve between continuous moderate‐intensity exercise + prior carbohydrate and intermittent high‐intensity exercise + prior carbohydrate during exercise and recovery was not significant [0.2 mmol/l (95% CI –0.7, 1.1); P = 0.635], nor was the difference in peak blood glucose level after adjusting for baseline level [0.2 mmol/l (95% CI –0.7, 1.1); P = 0.695]. The difference in marginal mean time‐averaged area under the blood glucose curve between continuous moderate‐intensity and intermittent high‐intensity exercise during exercise and recovery was also not significant [–0.2 mmol/l (95% CI –1.2, 0.8); P = 0.651]. Conclusions When carbohydrates are ingested prior to moderate‐intensity exercise, adding repeated sprints is not significantly detrimental to glycaemic management in overnight fasted people with Type 1 diabetes under basal insulin conditions.