Metabolic biomarkers following a short and long bout of high-intensity functional training in recreationally trained men

Abstract

Glucose regulation is a fundamental process of metabolic function, and is acutely altered by physical activity. High-Intensity Functional Training (HIFT) is a form of exercise performed using combinations of various modalities and durations. It is unknown if the metabolic responses to HIFT are similar to more commonly studied modalities (e.g., cycling and treadmill exercise), or if exercise duration will influence glucose regulation. The purpose of this study was to determine the effect of a Short (< 5-min) and Long (15-min) bout of HIFT on plasma metabolic biomarkers. Ten apparently healthy males (28.11 ± 5.09yrs) participated in this study. Two HIFT sessions (SHORT and LONG) were performed in a crossover fashion. Blood plasma was collected at four time points: PRE, POST, 1HR, and 3HR in order to examine glucose (GLU), insulin (INS), epinephrine (E), and norepinephrine (NE) responses. No trial dependent difference between the SHORT and LONG bouts in GLU (p=0.054), INS (p=0.671), E (p=0.078), and NE (p=0.194). A time effect was observed in both bouts only at POST for GLU (p<0.001), INS (p=0.011), E (p<0.001), and NE (p<0.001). All times returned to baseline values (p>0.05), except for lowered 3HR E (p=0.007). This study demonstrated that both SHORT and LONG bouts of HIFT elicited GLU, INS, E, and NE responses similar to those reported in response to high-intensity treadmill and cycling exercise, and that duration of the HIFT bouts may not be a determining factor in glucose regulation in healthy individuals.