Title page for ETD etd-04032017-222824


Type of Document Dissertation
Author Allerton, Timothy
Author's Email Address taller2@lsu.edu
URN etd-04032017-222824
Title The Immediate and Extended Effect of Diet and Exercise on Metabolic Flexibility
Degree Doctor of Philosophy (Ph.D.)
Department Kinesiology
Advisory Committee
Advisor Name Title
Johannsen, Neil Committee Chair
Irving, Brian Committee Member
Landin, Dennis Committee Member
Nelson, Arnold Committee Member
Primeaux, Stefany Committee Member
Spielmann, Guillaume Committee Member
Van Gemmert, Arend Committee Member
Romeo, Laurel Dean's Representative
Keywords
  • metabolism
  • exercise
  • high intensity interval training
  • metabolic flexibility
  • mitochondrial function
Date of Defense 2017-03-30
Availability unrestricted
Abstract
Metabolic inflexibility is an emerging physiological marker indicative of metabolic dysfunction and associated with type 2 diabetes (T2D) and obesity. Exercise is a potent stimulus to improve metabolic health, however, not much is known about the acute effects of exercise on metabolic flexibility (METFLEX). The purpose of this dissertation was study the time-course of diet and exercise and its effects on METFLEX. Three studies were conducted to investigate molecular and clinical aspects of diet and exercise and how these stimuli may alter the metabolic response to fuel.

The first study was conducted on obesity-prone, Osborne-Mendel (OM) and obesity-resistant S5B/Pl (S5B) rats. This experiment investigated inherent differences in EE, metabolic rate, METFLEX and skeletal muscle markers of metabolism, lipid storage and lipid oxidation between OM and S5B, as well as HFD-induced strain differences in these parameters. The consumption of a HFD in S5B rats increased metabolic rate and EE and decreased metabolic rate and EE in OM rats. These strain differences were not due to the differences in activity or food intake. These results suggest that HFD-induced differences in metabolic rate and EE may be mediated by HFD-induced differences in pAMPK and PPARγ expression and lipid accumulation in the gastrocnemius muscle of OM and S5B rats.

The second study was designed to investigate the effect of acute aerobic exercise at an intensity that maximizes the rate of fat oxidation (FATMAX) on glucose tolerance, insulin action, and metabolic flexibility (METFLEX) compared to acute aerobic exercise at the onset of blood lactate accumulation (OBLA) resulting in greater carbohydrate (CHO) oxidation. OBLA exercise appears to have deleterious effects on oral glucose tolerance and metabolic flexibility acutely, however, FM exercise does not confer improved METFLEX. These results suggest that predominate substrate utilization does not promote improved glucose tolerance and metabolic flexibility in young overweight men. The third and final study of this dissertation was designed to investigate the immediate and extended of a single bout of high intensity interval exercise (HIIE) on METFLEX and mitochondrial function. Participants were recruited with a family history (FmHx) of T2D (n=8) and without a family history of T2D (n=8). The extended effects (48 hours) work via the reduction fat oxidation by increasing resting fat oxidation rate and improving the suppression of fat oxidation in response to a mixed meal.

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