Effects of a Pre-Exercise Meal on Plasma Growth Hormone Response and Fat Oxidation during Walking.
The purpose of this study was to determine the effects of a pre-exercise meal on the plasma human growth hormone (hGH) response and fat oxidation during walking. Subjects (n=8) were randomly provided with either 1 g/kg body weight of glucose in 200 mL water (CHO) or 200 mL water alone (CON) 30 min prior to exercise and subsequently walked on a treadmill at 50% of VO2max for 60 min. Plasma hGH concentrations were significantly higher in subjects who received CHO compared to those who received CON at 15 and 30 min. The fat oxidation rate in the CHO was significantly lower than the CON while walking for 5~15, 25~35 and 45~55 min. Plasma FFA levels were also significantly lower in the CHO compared to the CON at 30, 45 and 60 min. Plasma glucose levels in the CHO were significantly lower while plasma insulin levels were significantly higher than in the CON at 15 and 30 min. Therefore, the results of this study suggest that the elevation of plasma hGH levels due to the intake of a pre-exercise meal may not be strongly related to fat oxidation and plasma free fatty acid (FFA) levels during low-intensity exercise.
Exercise Metabolism Laboratory, Kyungpook National University, Daegu 702-701, Korea.
Young-Ho
YH
Shin
Exercise Metabolism Laboratory, Kyungpook National University, Daegu 702-701, Korea.
Hyun-Lyung
HL
Jung
Exercise Metabolism Laboratory, Kyungpook National University, Daegu 702-701, Korea.
Jong-Woo
JW
Ryu
Department of Judo, Yong In University, Gyeonggi 449-714, Korea.
Pan-Soo
PS
Kim
Division of Metabolism and Functionality Research, Korea Food Research Institute, Gyeonggi 463-746, Korea.
Tae-Yeol
TY
Ha
Division of Metabolism and Functionality Research, Korea Food Research Institute, Gyeonggi 463-746, Korea.
Ji-Yoon
JY
An
Exercise Metabolism Laboratory, Kyungpook National University, Daegu 702-701, Korea.
Ho-Youl
HY
Kang
cabohydrate; fat oxidation; free fatty acid; human growth hormone; walking