Interval Walking Best for Diabetics

By Sondra Forsyth

Research done by by Dr. Thomas Solomon, and colleagues at the University of Copenhagen in Denmark and published in August 2014 in Diabetologia suggests that training with alternating levels of walking intensity, known as interval training, could be better than walking at a constant speed to help manage blood sugar in people with type 2 diabetes.

A release from the publisher notes that the effects of exercise on glycemic control in patients with type 2 diabetes are well documented, but that the optimal exercise intensity and type remains to be defined. Traditionally, high-intensity exercise has not been recommended for type 2 diabetics due to a fear of inducing injuries and discouraging patients from continuing with the exercise program. Nevertheless, high-intensity exercise improves glycemic control more than low-intensity exercise.

Other research by the same authors showed that interval-walking training (IWT), more favorably improve glycemic control in people with type 2 diabetes when compared to continuous-walking training (CWT) matched to have the same overall energy expenditure. In the 2014 study, the authors analyze the potential mechanisms behind this effect.

Patients with type 2 diabetes were randomized to 3 groups: a control group (CON), an IWT group and an energy-expenditure matched CWT group. Training groups were prescribed highly standardized but free-living and unsupervised training, five 60 minute sessions per week. A hyperglycemic clamp was used to measure insulin secretion, a standard method whereby glucose is infused at a constant rate and then used to work out how much insulin is being produced. Glucose isotope tracers were infused to measure glucose metabolism, and skeletal muscle biopsies were taken to assess insulin signaling. These variables were measured before and after a 4-month intervention.

The researchers found that improved blood sugar control was only evident in the IWT group, and this was likely to be caused by IWT-induced increases in insulin sensitivity and increased peripheral glucose disposal, indicative of improved glucose metabolism No changes occurred in the CWT or CON groups. Furthermore, only IWT improved insulin signaling in skeletal muscle.

The authors conclude: “The most important finding of this study is that IWT, but not CWT, increased insulin sensitivity without a compensatory decrease in insulin secretion, thus improving the overall impact of insulin on blood sugar in these patients. Whether these beneficial effects of IWT continue and result in better health outcomes in the long term must be determined in order to justify the clinical utility of interval training for people with type 2 diabetes.”