'Exercise snacks' before meals: a novel strategy to improve glycaemic control in individuals with insulin resistance.
Level 2 - randomized trial
Randomized crossover trial
PubMed 24817675 · doi:10.1007/s00125-014-3244-6
What was done
Nine individuals with insulin resistance completed three exercise interventions in randomized order. Glycaemic measures were recorded across 3 days with exercise performed on the middle day under controlled meal timing and composition: (1) traditional continuous exercise (CONT) comprising 30 min of moderate-intensity (60% maximal heart rate [HRmax]) incline walking before dinner; (2) exercise snacking (ES) comprising 6 x 1 min intense (90% HRmax) incline walking intervals 30 min before each meal; or (3) composite exercise snacking (CES) comprising 6 x 1 min intervals alternating walking and resistance exercise 30 min before meals.
What was found
ES attenuated mean 3-hour postprandial glucose following breakfast by 1.4 ± 1.5 mmol/l (p = 0.02) but not lunch (0.4 ± 1.0 mmol/l, p = 0.22). Following dinner, ES was more effective than CONT (0.7 ± 1.5 mmol/l below CONT, p = 0.04). ES also reduced 24-hour mean glucose concentration by 0.7 ± 0.6 mmol/l (p = 0.01), persisting over the subsequent 24 hours (0.6 ± 0.4 mmol/l lower vs CONT relative to baseline, p = 0.01). CES was equally effective as ES across all glycaemic variables (p > 0.05).
Why it matters
Dosing brief, intense bouts of physical activity before meals offers a time-efficient strategy that improves acute postprandial and 24-hour glycaemic control more effectively than a single moderate-intensity exercise session in insulin-resistant individuals.
Limits
The sample size was very small (n = 9). The study tested only acute effects over 3 days, leaving long-term adherence, clinical outcomes, and safety unmeasured. Specific participant demographics (such as age or sex) were not detailed in the abstract.
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