The effects of free-living interval-walking training on glycemic control, body composition, and physical fitness in type 2 diabetic patients: a randomized, controlled trial.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 23002086 · doi:10.2337/dc12-0658
What was done
Thirty-two individuals with type 2 diabetes were randomized to a control group (n = 8), a continuous-walking group (n = 12), or an interval-walking group (n = 12) for a 4-month free-living intervention. Both exercise groups were prescribed five 60-minute sessions per week, monitored with accelerometers and heart-rate monitors. The continuous group walked at moderate intensity, while the interval group alternated 3-minute repetitions of low and high intensity. Outcomes measured before and after the intervention included VO2max, body composition (fat mass and visceral fat), and glycemic control via fasting glucose, HbA1c, oral glucose tolerance tests, and continuous glucose monitoring (CGM).
What was found
Adherence across training groups was 89 ± 4%, with comparable energy expenditure and mean intensity between continuous and interval walkers. VO2max increased by 16.1 ± 3.7% in the interval-walking group (P < 0.05), with no changes observed in the continuous-walking or control groups. Body mass, fat mass, and visceral fat decreased significantly only in the interval-walking group (P < 0.05). In the control group, glycemic control worsened (increased mean CGM glucose and fasting insulin, P < 0.05). In the interval-walking group, mean CGM glucose (P = 0.05) and maximum CGM glucose (P < 0.05) decreased, while continuous walkers showed no significant changes in glycemic control.
Why it matters
The study demonstrates that intensity variation, rather than total energy expenditure alone, drives improvements in aerobic fitness, body composition, and continuous glycemic profiles in patients with type 2 diabetes. It establishes interval walking as an effective, feasible free-living exercise strategy for this population.
Limits
The total sample size was small (32 participants across three arms), limiting statistical power. The abstract reports p-values without confidence intervals or absolute values for body mass and glucose metrics, and it does not detail long-term adherence or safety beyond the 4-month period.
Cited by
- supports Interval walking alternating between 75% and 60% intensity produces greater improvements in 24-hour glucose regulation, waist circumference, BMI, and HbA1c than continuous walking at 65% intensity.