Three 15-min bouts of moderate postmeal walking significantly improves 24-h glycemic control in older people at risk for impaired glucose tolerance.
Level 2 - randomized trial
Randomized crossover trial with within-subject controls
PubMed 23761134 · doi:10.2337/dc13-0084
What was done
Ten inactive older adults (aged ≥60 years, BMI <35 kg/m², fasting blood glucose 105–125 mg/dL) completed three randomly ordered 48-hour protocols in a whole-room calorimeter, spaced 4 weeks apart. In each protocol, day 1 served as a control day and day 2 involved treadmill walking at 3 METs in one of three regimens: 1) three 15-minute postmeal walks, 2) 45 minutes of sustained walking at 10:30 a.m., or 3) 45 minutes of sustained walking at 4:30 p.m. Continuous glucose monitoring measured interstitial glucose, and respiratory exchange measured substrate utilization over 48 hours.
What was found
Both 45 minutes of sustained morning walking (127 ± 23 vs. 118 ± 14 mg/dL) and three 15-minute postmeal walks (129 ± 24 vs. 116 ± 13 mg/dL) significantly reduced 24-hour mean glucose compared to control days (P < 0.05). In addition, postmeal walking was significantly more effective (P < 0.01) than either morning or afternoon sustained walking for reducing 3-hour post-dinner glucose levels compared to control.
Why it matters
Breaking daily exercise into short 15-minute bouts timed immediately after meals may manage postprandial glucose surges in older individuals with impaired fasting glucose more effectively than a single longer exercise session.
Limits
The sample size was very small (n = 10). The trial only evaluated acute, single-day exercise effects inside a whole-room calorimeter, so long-term adherence and effectiveness under free-living conditions remain unmeasured. Substrate utilization numbers were not reported in the abstract.
Cited by
- supports Performing 10 to 15 minutes of physical activity immediately following a meal reduces the postprandial glucose excursion by 50% or more.