High-Intensity Training Improves Plasma Glucose and Acid-Base Regulation During Intermittent Maximal Exercise in Type 1 Diabetes

Abstract

In individuals without diabetes, high-intensity exercise (HIE) training may reduce (1) the characteristic postexercise rise in plasma glucose with HIE (2–4) and reduces (5,6) the marked acid-base balance perturbations (5–8). In type 1 diabetes, continuous HIE induces sustained hyperglycemia (9,10), while very brief intermittent HIE may reduce hyperglycemia (11). Acid-base disturbances during exercise may be heightened in type 1 diabetes (12–14). Effects of HIE training on glycemia and acid-base balance during intermittent HIE in type 1 diabetes are unknown; thus, despite the potential clinical importance of such exercise, there is no evidence on which to base patient guidelines. The aim of the present study was thus to investigate the effects of HIE training on glycemia and acid-base regulation during intermittent HIE in type 1 diabetes. Eight subjects with type 1 diabetes (duration of diabetes 7.1 ± 4.0 years) and seven subjects without diabetes (control group), all of whom were healthy and took no medications (other than insulin in type 1 diabetic subjects), consented to participate. The study was approved by the human ethics committees of The University of Sydney and the South Sydney West Area Health Service. Control subjects closely matched those with diabetes for age (type 1 diabetes 25 ± 4 years and control 25 ± 4 years), BMI (25.4 ± 3.2 and 23.8 ± 5.0 kg/m2, respectively), and V o2peak (42.7 ± 12.2 and 43.7 ± 6.2 ml · kg−1 · min−1), as detailed in a related study that reported effects of sprint training on muscle sodium-potassium ATPase and on plasma potassium during maximal exercise (15). Testing was conducted after overnight fasting. Type 1 diabetic subjects delayed their morning insulin. Subjects completed four 30-s maximal exercise bouts (EB1–4) (each separated by …