title: Comparison of the effects of acute exercise after overnight fasting and breakfast on energy substrate and hormone levels in obese men.
abstract: [Purpose] We compared the effects of acute aerobic exercise following overnight fasting and breakfast on energy substrate and hormone levels in obese male college students. [Subjects and Methods] This crossover study recruited 10 obese male college students with a body mass index >25 kg/m(2) or >20% body fat. One week post-recruitment, the subjects exercised in the morning after an overnight fast. At 2 weeks, they exercised post-breakfast. Energy substrate (glucose, free fatty acid) and metabolic hormone (insulin, growth hormone, and cortisol) levels were measured immediately before and after exercise and at 60 min post-exercise. [Results] We observed interaction effects between the measurement time and exercise treatment for glucose; significant differences between measurement times and between exercise treatments for free fatty acids; interaction effects between the measurement time and exercise treatment for insulin and significant differences in the measurement time; significance differences between measurement times and between exercise treatments for growth hormone; and significant differences between measurement times and between exercise treatments for cortisol. [Conclusion] Morning exercise following an overnight fast can be more effective in reducing body fat than post-prandial exercise. However, increased cortisol levels following exercise after overnight fasting may negatively affect long-term weight loss in obese men.
authors.affiliation: Department of Physiology, College of Medicine, Kyung Hee University, Republic of Korea.
authors.forename: Tae Woon
authors.initials: TW
authors.lastname: Kim
authors.affiliation: School of Sport Science, Sungkyunkwan University, Republic of Korea.
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: School of Sport Science, Sungkyunkwan University, Republic of Korea.
authors.forename: Kyu Hwan
authors.initials: KH
authors.lastname: Choi
authors.affiliation: School of Sport Science, Sungkyunkwan University, Republic of Korea.
authors.forename: Dong Hyun
authors.initials: DH
authors.lastname: Kim
authors.affiliation: School of Protection Science, Kyungwoon University, Republic of Korea.
authors.forename: Tae Kyung
authors.initials: TK
authors.lastname: Han
keywords: Energy substrates; Exercise; Metabolic hormone