Document Type

Thesis

Degree Name

Master of Kinesiology (MKin)

Department

Kinesiology and Physical Education

Faculty/School

Faculty of Science

First Advisor

Dr. Tom Hazell

Advisor Role

Supervisor

Abstract

Acute moderate-intensity exercise transiently suppresses appetite via fluctuations in the appetite-regulatory peptides acylated ghrelin (AG), peptide tyrosine-tyrosine3-36 (PYY3-36), and active glucagon-like peptide-1 (GLP-1). Importantly, these effects do not lead to compensatory changes in energy intake in normal weight or obese individuals, highlighting the potential for exercise to induce acute energy deficits. One potential mechanism for these effects is increased post-exercise plasma concentrations of interleukin (IL)-6, as IL-6 has demonstrated appetite-inhibitory effects in animal and cell culture models. Given obesity is characterized by a state of chronic low-grade inflammation and associated with upregulated IL-6, this study sought to determine whether IL-6 plays a role in the appetite-inhibitory effects of moderate-intensity continuous exercise in humans by utilizing an obese human model. Six lean and six obese sedentary males completed one non-exercise control (CTRL) and one training session (EX: 60 min, 65% V̇O2max). IL-6, active GLP-1, PYY3-36, AG, and appetite perceptions were measured fasted, pre-, as well as 30, 90, and 150 min post-exercise. Fasted IL-6 and active GLP-1 were greater (P≤0.031) in the obese vs lean group but there were no differences (P>0.05) in fasted AG or PYY3-36. IL-6 tended to increase in both groups post-exercise (P=0.053), however AG decreased in the lean group only (P<0.001) with no observable effects of exercise on active GLP-1 (P=0.338), PYY3-36 (P=0.130), or overall appetite (P=0.405) in either group. Further, IL-6 was found to moderate the effects of AG and PYY3-36, but not active GLP-1, at certain time points post-exercise favouring a reduction in overall appetite. In summary, we observed little difference in the appetite-regulatory and perceptual response to EX between lean and obese sedentary males and were unable to conclusively establish whether IL-6 mediates the effects of exercise on appetite regulation.

Convocation Year

2018

Convocation Season

Fall

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