Effects of Fasted State on High-Intensity Interval Training vs. Light Aerobic Exercise Training

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Kaitlyn Bigner Ella Kuhr Pierce Boyne


By Kaitlyn Bigner, Health Sciences; Ella Kuhr, Health Sciences

Advisor: Pierce Boyne

Presentation ID: PM_B39

Abstract: Fasting before exercise is a recent popularized trend that is purported to burn fat quicker. High-intensity interval training (HIIT) and moderate aerobic exercise (AE) are popular forms of exercise that stress the body in different ways. However, the ideal fasted exercise is unknown and the relationship between fasted exercise and the physiologic effects on the body has been understudied. This study aimed to establish the metabolic and performance effects of fasting during HIIT vs. AE in healthy adults. Participants include uninjured 18-25 years old recruited from an undergraduate Health Sciences program. Each participant wore a heart rate (HR) monitor and performed 4 separate visits in randomized order: 1) non-fasted HIIT; 2) fasted HIIT; 3) non-fasted AE; and 4) fasted AE. Fasted exercise was described as exercise after abstinence of food for 12-hours. The HIIT exercise involved a 2-minute warm-up jog with two 4-minute sprints at ~90% age-predicted maximal HR followed by 3 minutes of jogging at ~70% age-predicted maximal HR. The AE involved a 2-minute warm-up jog followed by 14 minutes of running at ~70% age-predicted maximal HR. Respiratory gases were collected through a metabolic cart to measure peak oxygen consumption rate (VO2) and respiratory exchange ratio (RER). These, along with rate of perceived exertion (RPE) were used to determine performance and metabolic effects. Descriptive statistics were calculated for all variables and paired t-tests were used to determine differences between fasted and non-fasted HIIT and AE groups.

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PM Poster Session -- Great Hall -- B: Health & Body