Hormonal responses to a 160-km race across frozen Alaska

Kraemer, William, Fragala, Maren, Watson, Greig, Volek, Jeff, Rubin, Martyn, French, Duncan, Maresh, Carl, Vingren, Jakob, Hatfield, Disa, Spiering, Barry, Yu-Ho, Jen, Hughes, Sherri, Case, H. S., Stuempfle, Kristin, Lehmann, Donald, Bailey, Stephen and Evans, Debbie (2008) Hormonal responses to a 160-km race across frozen Alaska. British Journal of Sports Medicine, 42 (2). pp. 116-120. ISSN 0306-3674

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Official URL: http://dx.doi.org/10.1136/bjsm.2007.035535

Abstract

Background: Severe physical and environmental stress seems to have a suppressive effect on the hypothalamic–pituitary–gonadal (HPG) axis in men. Examining hormonal responses to an extreme 160-km competition across frozen Alaska provides a unique opportunity to study this intense stress. Objective: To examine hormonal responses to an ultra-endurance race.
Methods: Blood samples were obtained from 16 men before and after racing and analyzed for testosterone, interleukin-6 (IL-6), growth hormone (GH) and cortisol. Six subjects (mean (SD) age 42 (7) years; body mass 78.9 (7.1) kg; height 1.78 (0.05) m raced by bicycle (cyclists) and 10 subjects (age 35 (9) years; body mass 77.9 (10.6) kg; height, 1.82 (0.05) m) raced by foot (runners). Mean (SD) finish times were 21.83 (6.27) and 33.98 (6.12) h, respectively.
Results: In cyclists there were significant (p?0.05) mean (SD) pre-race to post-race increases in cortisol (254.83 (135.26) to 535.99 (232.22) nmol/l), GH (0.12 (0.23) to 3.21 (3.33) µg/ml) and IL-6 (2.36 (0.42) to 10.15 (3.28) pg/ml), and a significant decrease in testosterone (13.81 (3.19) to 5.59 (3.74) nmol/l). Similarly, in runners there were significant pre-race to post-race increases in cortisol (142.09 (50.74) to 452.21 (163.40) ng/ml), GH (0.12 (0.23) to 3.21 (3.33) µg/ml) and IL-6 (2.42 (0.68) to 12.25 (1.78) pg/ml), and a significant decrease in testosterone (12.32 (4.47) to 6.96 (3.19) nmol/l). There were no significant differences in the hormonal levels between cyclists and runners (p>0.05).
Conclusions: These data suggest a suppression of the hypopituitary–gonadal axis potentially mediated by amplification of adrenal stress responses to such an ultra-endurance race in environmentally stressful conditions.

Item Type: Article
Subjects: C800 Psychology
Department: Faculties > Health and Life Sciences > School of Life Sciences > Sport, Exercise and Rehabilitation
Depositing User: EPrints Services
Date Deposited: 01 Mar 2011 12:12
Last Modified: 10 Aug 2015 11:46
URI: http://nrl.northumbria.ac.uk/id/eprint/1992

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