Effects of Exercise Training on Fat Oxidation in Untrained Overweight and Obese Females

Author

Kelly Manning, Georgia State UniversityFollow

Date of Award

Summer 8-11-2011

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Kinesiology and Health

First Advisor

Jeffrey C. Rupp, Ph.D. - Chair

Second Advisor

Dan Benardot, Ph.D.

Third Advisor

L. Jerome Brandon, Ph.D.

Fourth Advisor

J. Andrew Doyle, Ph.D.

Abstract

This study examined whether a high-intensity interval (IT) or a continuous steady-state (CT) exercise training program had the greatest effect on fat oxidation rates and fat mass loss in a population of untrained overweight and obese females. Thirteen female subjects (VO_2peak 30.6 ± 1.29 ml^.kg^.min^-1, BMI 29 ± 0.79, fat mass [FM] 33.3 ± 2.09 kg) were randomly assigned to either a CT (exercise at the relative intensity that elicits the maximal fat oxidation rate [FAT_max] ) or an IT (intervals alternating 5 minutes at 40% and 85% VO_2peak) training group that exercised approximately 1 hour, 3 days^.week^-1 for 10 weeks. Body composition assessments, peak oxygen uptake (VO_2peak), FAT_max and plasma free fatty acid (FFA) concentrations were examined pre- and post-training using dual-energy X-ray absorptiometry (DEXA), ParvoMedics gas analysis system and FFA half micro tests (Roche Diagnostics). No significant differences were found post-training in body weight (kg), body fat (%), fat-free mass, or fat mass (P>0.05). The relative exercise intensity that elicited FAT_max was significantly increased from 35.3 ± 2.55% to 44.7 ± 3.56% in the IT group post-training (P <0.05). The maximal fat oxidation rate was determined at a higher relative exercise intensity after 10 weeks of a IT program compared with a CT program, which resulted in longer durations of fat oxidation during submaximal exercise bouts. These data suggest that an IT program induces a greater increase in the relative exercise intensity that elicits maximal fat oxidation after 10 weeks of training compared to a CT program in this population. Although body composition and FAT_max were not altered, it is possible that through training induced metabolic adaptations from the IT program, intramuscular triacylglyceride (IMTG) contributions to fat oxidation at a given steady-state work rate could be increased post-training.

DOI

https://doi.org/10.57709/2102854

Recommended Citation

Manning, Kelly, "Effects of Exercise Training on Fat Oxidation in Untrained Overweight and Obese Females." Dissertation, Georgia State University, 2011.
doi: https://doi.org/10.57709/2102854