Mechanisms behind the superior effects of interval vs continuous training on glycaemic control in individuals with type 2 diabetes: a randomised controlled trial

• Published in: Diabetologia 2014-10, Vol.57 (10), p.2081-2093
• Main Authors: Karstoft, Kristian, Winding, Kamilla, Knudsen, Sine H., James, Noemi G., Scheel, Maria M., Olesen, Jesper, Holst, Jens J., Pedersen, Bente K., Solomon, Thomas P. J.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Blood Glucose - drug effects; Diabetes; Diabetes Mellitus, Type 2 - blood; Diabetes Mellitus, Type 2 - drug therapy; Diabetes Mellitus, Type 2 - therapy; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Exercise intensity; Exercise Therapy - methods; Female; Glucagon; Glucose; Health sciences; Human Physiology; Humans; Hyperglycemia; Infectious diseases; Insulin; Insulin - therapeutic use; Internal Medicine; Interval training; Male; Medical sciences; Medical screening; Medicine; Medicine & Public Health; Metabolic Diseases; Middle Aged; Musculoskeletal system; Peptides; Physical fitness
• ISSN: 0012-186X; 1432-0428
• DOI: 10.1007/s00125-014-3334-5

Aims/hypothesis By use of a parallel and partly crossover randomised, controlled trial design we sought to elucidate the underlying mechanisms behind the advantageous effects of interval walking training (IWT) compared with continuous walking training (CWT) on glycaemic control in individuals with type 2 diabetes. We hypothesised that IWT, more than CWT, would improve insulin sensitivity including skeletal muscle insulin signalling, insulin secretion and disposition index (DI). Methods By simple randomisation (sequentially numbered, opaque sealed envelopes), eligible individuals (diagnosed with type 2 diabetes, no exogenous insulin treatment) were allocated to three groups: a control group (CON, n  = 8), an IWT group ( n  = 12) and an energy expenditure-matched CWT group ( n  = 12). Training groups were prescribed free-living training, five sessions per week (60 min/session). A three-stage hyperglycaemic clamp, including glucose isotope tracers and skeletal muscle biopsies, was performed before and after a 4 month intervention in a hospitalised setting. No blinding was performed. Results The improved glycaemic control, which was only seen in the IWT group, was consistent with IWT-induced increases in insulin sensitivity index (49.8 ± 14.6%; p