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Glucose metabolism in type 2 diabetes better with interval vs. continuous walking
Alternating walking intensity helped patients with type 2 diabetes manage blood glucose levels better than stepping at a constant speed, according to research published in Diabetologia.
Interval walking training (IWT) maintained insulin secretion and improved insulin sensitivity and disposition index (DI) compared with continuous walking training (CWT) that required the same energy expenditure.
“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,” the researchers wrote.
Kristian Karstoft, MD, of the University of Copenhagen, Denmark, and colleagues studied patients with type 2 diabetes, not receiving exogenous insulin, who were randomized to IWT (n=12), CWT (n=12) or control (n=8) over 4 months.
Participants were prescribed five 60-minute training sessions per week, with freedom to train as desired. IWT consisted of alternating 3-minute intervals of fast walking (≥70% of an individual’s peak energy expenditure walking rate) and slow walking (approximately 40% of peak). CWT comprised continuous walking at moderate intensity (≥55%). The control group continued their lifestyle as usual. Hyperglycemic clamp, including glucose isotope tracers and skeletal muscle biopsies, was performed in a hospitalized setting before and after the intervention.
Improved glycemic control, only observed in the IWT group, aligned with IWT-induced increases in insulin sensitivity index (49.8±14.6%; P<.001), peripheral glucose disposal (14.5±4.9%; P<.05) and DI (66.2±21.8%; P<.001). There were no changes with CWT or the control group.
Further, only patients assigned IWT showed improved insulin signaling in skeletal muscle through increased insulin-stimulated AS160 protein phosphorylation (29.0±10.8%; P<.05).
No insulin secretion changes were witnessed during hyperglycemia alone, hyperglycemia plus glucagon-like peptide 1 infusion or arginine injection.
“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,” the researchers wrote.
Disclosure: Please see study for full list of financial disclosures.