Single bout of low-intensity exercise produces modestly favorable changes in glycemic and lipidemic profiles after ingestion of non-isoglucidic breakfasts.

OBJECTIVES: The aim of this study was to investigate the acute effects of low-intensity exercise on the postprandial hormonal and metabolic milieu induced by breakfast consumption.

METHODS: Exercise began 100min after the initiation of breakfast consumption and consisted of cycling at 40% of maximum oxygen uptake for 20min. Three different breakfasts were used to elicit the postprandial state: B1 = skimmed milk (125 mL) and 30g corn flakes; B2 = skimmed milk (220 mL), 200g apple, 30g cocoa cream-filled sponge cake; B3 = skimmed milk (125 mL), 50g bread, 150g apple, and 15g hazelnut and cocoa spread. Nineteen young healthy participants (8M/11 F; body mass index 22.7 ± 0.5 kg/m2 ; age 31 ± 0.7 y) consumed the three breakfasts, as well as an oral glucose load (50-g oral glucose tolerance test), under either resting or exercise conditions, in a randomized-crossover fashion. Blood glucose, insulinemia, ghrelinemia, lipidemia, and satiety were measured throughout the studies. To evaluate the metabolic effects of exercise, the changes that glucose, insulin, ghrelin, free fatty acid exhibited in the interval 90 to 120min were analyzed with a two-way repeated measures analysis of variance (factor 1: type of oral test; factor 2: resting/exercise condition).

RESULTS: No interaction between the two factors was found for any of the examined variables. Light exercise produced a modest, significant decrease in blood glucose levels (P = 0.004) and a modest, significant increase in free fatty acid levels (P = 0.002) with respect to the resting condition.

CONCLUSIONS: These findings suggest that short, mild exercise has beneficial effects on postprandial metabolism and this may have direct bearing on the issue of counteracting the epidemic rising of sedentary lifestyle of the general population.