Effect of three breakfast interventions on blood glucose during low-intensity exercise performed on a treadmill

Abstract

The objective of this work was to evaluate blood glucose (BG) response during a low-intensity activity, preceded by the consumption of three different types of breakfast (BF). Fifteen Physical Education male students of mean age of 22.7 ± 2 years were evaluated. Three BF interventions were carried out on different days :fasting; BF1: cookie, juice, apple, cereal bar or BF2: 400 mL carbohydrate drink) 60 minutes before jogging/walking for 1 hour at 50-60% of maximum calculated HR (heart rate). Measurements of BG were taken at 60 and 30 minutes prior to activity and every 20 minutes during exercise. Heart rate, blood pressure (BP) and RPE were also monitored. Statistical analysis was by ANOVA with Tukey test and aimed to identify differences both in effect over time and between different BF interventions, to a signifi cance level of P < 0.05. The results indicate an absence of any difference in HR, BP or RPE response between the three procedures. There was a statistical difference in BG between BF1 and BF2 during the period immediately before exercise, but no differences were observed during exercise for any of the three treatments. In terms of behavior over time, BG at 30 minutes pre-exercise was signifi cantly higher than at other sample times, for both for BF1 and BF2. It was concluded that fasting or the levels of energy intake proposed in this study one hour before physical work did not cause alterations to the physiological responses of HR, RPE, BP or BG during that exercise activity.