Aims/hypothesis
We evaluated and compared the effects on glycaemic control of two different exercise protocols in elderly men with type 2
diabetes mellitus.
Methods
Eighteen patients with type 2 diabetes mellitus carried out home-based bicycle training for 5 weeks. Patients were randomly
assigned to one of two training programmes at 60% of maximal oxygen uptake: three 10 min sessions per day (3 × 10) or one
30 min session per day (1 × 30). Plasma insulin, C-peptide and glucose concentrations were measured during a 3 h oral glucose
tolerance test (OGTT). Insulin sensitivity index (ISIcomposite), pre-hepatic insulin secretion rates (ISR) and change in insulin secretion per unit change in glucose concentrations (Btotal) were calculated.
Results
Cardiorespiratory fitness increased in response to training in both groups. In group 3 × 10 (n = 9) fasting plasma glucose (p = 0.01), 120 min glucose OGTT (p = 0.04) and plasma glucose concentration areas under the curve at 120 min (p < 0.04) and 180 min (p = 0.07) decreased. These parameters remained unchanged in group 1 × 30 (n = 9). No significant changes were found in ISIcomposite, ISR and Btotal in either of the exercise groups. In a matched time-control group (n = 10), glycaemic control did not change.
Conclusions/interpretation
Moderate to high-intensity training performed at 3 × 10 min/day is preferable to 1 × 30 min/day with regard to effects on
glycaemic control. This is in spite of the fact that cardiorespiratory fitness increased similarly in both exercise groups.
A possible explanation is that the energy expenditure associated with multiple short daily sessions may be greater than that
in a single daily session.
Keywords Cardiovascular fitness - Energy expenditure - Exercise - Glycaemic control - Insulin resistance - Physical training - Skeletal muscle - Type 2 diabetes mellitus