4weeks of high-intensity interval training does not alter the exercise-induced growth hormone response in sedentary men.

Hiroto Sasaki,Toshiyuki Kurihara,Yuta Hasegawa,Ayaka Mori,Toshiaki Ijichi,Takuma Morishima,Kazushige Goto

doi:10.1186/2193-1801-3-336

Hiroto Sasaki, Toshiyuki Kurihara + Show 5 more

Open Access

https://doi.org/10.1186/2193-1801-3-336

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Journal: SpringerPlus	Publication Date: Jul 2, 2014
Citations: 58	License type: cc-by

Affiliation: Ritsumeikan University

Abstract

SummaryThis study determined the effects of high-intensity interval training on the exercise-induced growth hormone (GH) responses, whole body and regional fat content. Twenty-four sedentary males were randomized to either a high-intensity interval training (HIT) group or a low-intensity continuous training (LT) group. The HIT group performed intermittent exercises at 85% of , whereas the LT group performed continuous exercise for 22 min at 45% of . Before and after 4 weeks of training, hormonal and metabolic responses to acute exercise were determined. Acute exercise significantly increased GH concentrations in both groups (p < 0.05). However, the responses did not change after training period in either group. Furthermore, the training did not significantly affect intramyocellular or intrahepatic lipid content in either group. The present study indicates that 4 weeks of high-intensity interval training does not alter the exercise-induced GH responses, whole body fat mass or intramyocellular and intrahepatic lipid content in sedentary males.

Highlights

Growth hormone (GH) has been shown to affect substrate oxidation pattern and body composition, because GH promotes lipolysis and fat oxidation (Gravholt et al 1999)
Fasting blood samples There were no differences in serum TG, HDL-cholesterol and LDL-cholesterol concentrations between high-intensity interval training (HIT) (TG; 72 ± 8 mg/dl, HDL-cholesterol; 51 ± 2 mg/dl, LDLcholesterol; 105 ± 6 mg/dl) and low-intensity continuous training (LT) (TG; 80 ± 10 mg/dl, HDL-cholesterol; 53 ± 4 mg/dl, LDL-cholesterol; 88 ± 6 mg/dl) groups before the training period
No significant change was observed in dietary energy intake after the training period in either group (HIT group, 2375 ± 209 kcal/day vs. LT group, 2058 ± 271 kcal/day). To our knowledge, this is the first study to determine the effects of HIT on the exercise-induced GH response and ectopic fat accumulation

Summary

Introduction

Growth hormone (GH) has been shown to affect substrate oxidation pattern and body composition, because GH promotes lipolysis and fat oxidation (Gravholt et al 1999). GH secretion is influenced by a variety of physiological conditions, including age, gender, nutrition status, body composition, and physical fitness level (Salvadori et al 2010). In particular, is a potent stimulus of GH secretion (Gilbert et al 2008; Goto et al 2007; Kanaley et al 1997). The magnitude of exercise-induced GH secretion is dependent on the intensity (Pritzlaff et al 1999) and duration of exercise (Wideman et al 2006). The accumulation of whole body and visceral fat mass strongly attenuates GH secretion (Makimura et al 2008). Spontaneous (Eliakim et al 2006; Kanaley et al 1999) and

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