'Exercise snacks' before meals: a novel strategy to improve glycaemic control in individuals with insulin resistance

The aim of this study was to investigate whether small doses of intense exercise before each main meal ('exercise snacks') would result in better blood glucose control than a single bout of prolonged, continuous, moderate-intensity exercise in individuals with insulin resistance.

Nine individuals completed three exercise interventions in randomised order. Measures were recorded across 3 days with exercise performed on the middle day, as either: (1) traditional continuous exercise (CONT), comprising 30 min moderate-intensity (60% of maximal heart rate [HRmax]) incline walking before dinner; (2) exercise snacking (ES), consisting of 6 × 1 min intense (90% HRmax) incline walking intervals 30 min before each meal; or (3) composite exercise snacking (CES), encompassing 6 × 1 min intervals alternating between walking and resistance-based exercise, 30 min before meals. Meal timing and composition were controlled within participants for exercise interventions.

ES attenuated mean 3 h postprandial glucose concentration following breakfast (by 1.4 ± 1.5 mmol/l, p = 0.02) but not lunch (0.4 ± 1.0 mmol/l, p = 0.22), and was more effective than CONT following dinner (0.7 ± 1.5 mmol/l below CONT; p = 0.04). ES also reduced 24 h mean glucose concentration by 0.7 ± 0.6 mmol/l (p = 0.01) and this reduction persisted for the subsequent 24 h (lower by 0.6 ± 0.4 mmol/l vs CONT, relative to their baselines; p = 0.01). CES was just as effective as ES (p > 0.05 for all glycaemic variables) at improving glycaemic control.

Dosing exercise as brief, intense 'exercise snacks' before main meals is a time-efficient and effective approach to improve glycaemic control in individuals with insulin resistance.