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Nutritional status and the gonadotrophic response to a polar expedition

Lookup NU author(s): Dr David Woods

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Abstract

Polar expeditions have been associated with changes in the hypothalamic-pituitary-testicular axis consistent with central hypogonadism (i. e., decreased testosterone, luteinising hormone (LH), and follicle stimulating hormone (FSH)). These changes are typically associated with body mass loss. Our aim was to evaluate whether maintenance of body mass during a polar expedition could mitigate against the development of central hypogonadism. Male participants (n = 22) from a 42-day expedition (British Services Antarctic Expedition 2012) volunteered to take part in the study. Body mass, body composition, and strength data were recorded pre-and postexpedition in addition to assessment of serum testosterone, LH, FSH, thyroid hormones, insulin-like growth factor 1 (IGF-1), and trace elements. Energy provision and energy expenditure were assessed at mid-and end-expedition. Daily energy provision was 6335 +/- 149 kcal.day(-1). Estimated energy expenditure midexpedition was 5783 +/- 1690 kcal.day(-1). Body mass and percentage body fat did not change between pre-and postexpedition. Total testosterone (nmol.L-1) (14.0 +/- 4.9 vs. 17.3 +/- 4.0, p = 0.006), calculated free testosterone (pmol.L-1) (288 +/- 82 vs. 350 hypothalamic- 70, p = 0.003), and sex hormone binding globulin (nmol.L-1) (33 +/- 12 vs. 36 +/- 11, p = 0.023) concentrations increased. LH and FSH remained unchanged. Thyroid stimulating hormone (TSH; IU.L-1) (2.1 +/- 0.8 vs. 4.1 +/- 2.1, p < 0.001) and free triiodothyronine (FT3; IU.L-1) (5.4 +/- 0.4 vs. 6.1 +/- 0.8, p < 0.001) increased while free thyroxine, IGF-1, and trace elements remained unchanged. Hand-grip strength was reduced postexpedition but static lift strength was maintained. Maintenance of body mass and nutritional status appeared to negate the central hypogonadism previously reported from polar expeditions. The elevated TSH and free FT3 were consistent with a previously reported "polar T3 syndrome".

Publication metadata

Author(s): Woods DR, Delves SK, Britland SE, Shaw A, Brown PE, Bentley C, Hornby S, Burnett A, Lanham-New SA, Fallowfield JL

Publication type: Article

Publication status: Published

Journal: Applied Physiology, Nutrition, and Metabolism

Year: 2015

Volume: 40

Issue: 3

Pages: 292-297

Print publication date: 01/03/2015

Online publication date: 19/12/2014

Acceptance date: 17/12/2014

ISSN (print): 1715-5312

ISSN (electronic): 1715-5320

Publisher: NRC Research Press

URL: http://dx.doi.org/10.1139/apnm-2014-0418

DOI: 10.1139/apnm-2014-0418

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