Glucose regulation is a fundamental process of metabolic function, and is acutely altered by physical activity. Importantly, exercise intensity and duration have been shown to affect glucose regulation differently. High-Intensity Functional Training (HIFT) is a form of exercise performed using combinations of various modalities and durations. Though HIFT is of a high-intensity nature, it is unknown if different durations of HIFT will influence glucose regulation differently.
PURPOSE: To determine the effect of a Short (<5 min) and Long (15 min) bout of HIFT on plasma glucose and insulin concentration.
METHODS: Ten apparently healthy males (28.11 ± 5.09 yrs) participated in this study. Two HIFT sessions (SHORT and LONG) were performed in a crossover fashion. The SHORT bout consisted of 30 power clean-and-jerk lifts (61 kg) for time, while the LONG bout was a 15-min circuit of 250 m row, 20 kettle bell swings (24 kg), and 15 dumbbell (16 kg) squat presses performed for 15 min. Blood plasma was collected at four different times points: PRE, POST, 1HR, and 3HR in order to examine glucose (GLU) and insulin (INS) responses.
RESULTS: A repeated measures ANOVA showed no trial dependent difference between the SHORT and LONG bouts of HIFT in GLU (p = 0.109) or INS (p = 0.504). A time effect was observed in both bouts only at the POST time point for both GLU; Short: 83.9 ± 16 mg/dL vs. 110.3 ± 18 mg/dL (p < 0.001), Long: 84.5 ± 11 mg/dL vs. 124.6 ± 19 mg/dL and INS; Short: 7.9 ± 4 mU/L vs. 16.1 ± 7 mU/L, Long: 9.1 ± 7.8 mU/L vs. 13.7 ± 7.3 mU/L (p < 0.05).
CONCLUSIONS: This study demonstrated that the SHORT and LONG bouts of HIFT elicited similar glucose and insulin responses. Duration of the HIFT bouts may not be a determining factor in glucose regulation in healthy individuals. Further research is necessary to better understand the relationship of varying durations of HIFT on glucose regulation.