Abstract

Objective. To investigate sprint training effects on muscle metabolism during exercise in subjects with (T1D) and without (CON) type 1 diabetes.

Research design and methods. Eight subjects with T1D and seven CON matched for age, BMI, and maximum oxygen uptake (V̇O₂peak) undertook seven weeks of sprint training. Pretraining, subjects cycled to exhaustion at 130% V̇O₂peak. Posttraining subjects performed an identical test. Vastus lateralis biopsies at rest and immediately after exercise, were assayed for metabolites, high-energy phosphates, and enzymes. Arterialized venous blood drawn at rest and after exercise was analyzed for lactate and [H⁺]. Respiratory measures were obtained on separate days during identical tests; and during submaximal tests before and after training.

Results. Pretraining, maximal resting activities of hexokinase, citrate synthase and pyruvate dehydrogenase did not differ between groups. Muscle lactate accumulation with exercise was higher in T1D than CON and corresponded to indices of glycemia (HbA_1c; fasting plasma glucose), however glycogenolytic and glycolytic rates were similar. Posttraining, at rest, hexokinase activity increased in T1D, in both groups citrate synthase activity increased and pyruvate dehydrogenase activity decreased; during submaximal exercise fat oxidation was higher, and during intense exercise, peak ventilation and carbon dioxide output, plasma lactate and [H⁺], muscle lactate, glycogenolytic and glycolytic rates, and ATP degradation were lower in both groups.

Conclusions. High-intensity exercise training was well-tolerated; reduced metabolic destabilization (of lactate, H⁺, glycogenolysis/glycolysis and ATP) during intense exercise, and enhanced muscle oxidative metabolism in young adults with type 1 diabetes. The latter may have clinically-important health benefits. ACTRN012606000368538-ANZCTR.org