Hormonal and metabolic responses to repeated cycling sprints under different hypoxic conditions

Kon, Michihiro, Nakagaki, Kohei, Ebi, Yoshiko, Nishiyama, Tetsunari and Russell, Aaron P. 2015, Hormonal and metabolic responses to repeated cycling sprints under different hypoxic conditions, Growth hormone and IGF research, vol. 25, no. 3, pp. 121-126, doi: 10.1016/j.ghir.2015.03.002.

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Title Hormonal and metabolic responses to repeated cycling sprints under different hypoxic conditions
Author(s) Kon, Michihiro
Nakagaki, Kohei
Ebi, Yoshiko
Nishiyama, Tetsunari
Russell, Aaron P.ORCID iD for Russell, Aaron P. orcid.org/0000-0002-7323-9501
Journal name Growth hormone and IGF research
Volume number 25
Issue number 3
Start page 121
End page 126
Total pages 6
Publisher Elsevier
Place of publication Amsterdam, The Netherlands
Publication date 2015-06
ISSN 1532-2238
Keyword(s) Growth hormone
Supramaximal exercise
Systemic hypoxia
Science & Technology
Life Sciences & Biomedicine
Cell Biology
Endocrinology & Metabolism
Summary OBJECTIVE: Sprint exercise and hypoxic stimulus during exercise are potent factors affecting hormonal and metabolic responses. However, the effects of different hypoxic levels on hormonal and metabolic responses during sprint exercise are not known. Here, we examined the effect of different hypoxic conditions on hormonal and metabolic responses during sprint exercise. DESIGN: Seven male subjects participated in three experimental trials: 1) sprint exercise under normoxia (NSE); 2) sprint exercise under moderate normobaric hypoxia (16.4% oxygen) (HSE 16.4); and 3) sprint exercise under severe normobaric hypoxia (13.6% oxygen) (HSE 13.6). The sprint exercise consisted of four 30s all-out cycling bouts with 4-min rest between bouts. Glucose, free fatty acids (FFA), blood lactate, growth hormone (GH), epinephrine (E), norepinephrine (NE), and insulin concentrations in the HSE trials were measured before exposure to hypoxia (pre 1), 15 min after exposure to hypoxia (pre 2), and at 0, 15, 30, 60, 120, and 180 min after the exercise performed in hypoxia. The blood samples in the NSE trial were obtained in normoxia at the same time points as the HSE trials. RESULTS: Circulating levels of glucose, FFA, lactate, GH, E, NE, and insulin significantly increased after all three exercise trials (P < 0.05). The area under the curve (AUC) for GH was significantly higher in the HSE 13.6 trial than in the NSE and HSE 16.4 trials (P < 0.05). A maximal increase in FFA concentration was observed at 180 min after exercise and was not different between trials. CONCLUSION: These findings suggest that severe hypoxia may be an important factor for the enhancement of GH response to all-out sprint exercise.
Language eng
DOI 10.1016/j.ghir.2015.03.002
Field of Research 119999 Medical and Health Sciences not elsewhere classified
110602 Exercise Physiology
Socio Economic Objective 929999 Health not elsewhere classified
HERDC Research category C1 Refereed article in a scholarly journal
ERA Research output type C Journal article
Copyright notice ©2015, Elsevier
Persistent URL http://hdl.handle.net/10536/DRO/DU:30078339

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