To explore the effects of the first all-female transantarctic expedition on hormonal axes pertinent to reproductive and metabolic function.
Six females (age, 28–36 yr; body mass index, 24.2 ± 0.97 kg·m−2) hauled 80-kg sledges 1700 km in 61 d. Estimated average energy intake was 20.8 ± 0.1 MJ·d−1 (4970 ± 25 kcal·d−1). Whole and regional body composition was measured by dual-energy x-ray absorptiometry 1 and 2 months before and 15 d after, the expedition. Body fat was also estimated by skinfold and bioimpedance immediately before and after the expedition. Basal metabolic and endocrine blood markers and, after 0.25 mg dexamethasone suppression, 1-h 10-μg gonadorelin and 1.0 μg adrenocortiocotrophin-(1–24) tests were completed, 39–38 d preexpedition and 4 to 5 d and 15 to 16 d postexpedition. Cortisol was assessed in hair (monthly average concentrations) and saliva (five-point day curves and two-point diurnal sampling).
Average body mass loss was 9.37 ± 2.31 kg (P < 0.0001), comprising fat mass only; total lean mass was maintained. Basal sex steroids, corticosteroids, and metabolic markers were largely unaffected by the expedition except leptin, which decreased during the expedition and recovered after 15 d, a proportionately greater change than body fat. Luteinizing hormone reactivity was suppressed before and during the expedition, but recovered after 15 d, whereas follicle-stimulating hormone did not change during or after the expedition. Cortisol reactivity did not change during or after the expedition. Basal (suppressed) cortisol was 73.25 ± 45.23 mmol·L−1 before, 61.66 ± 33.11 mmol·L−1 5 d postexpedition and 54.43 ± 28.60 mmol·L−1 16 d postexpedition (P = 0.7). Hair cortisol was elevated during the expedition.
Maintenance of reproductive and hypothalamic-pituitary-adrenal axis function in women after an extreme physical endeavor, despite energy deficiency, suggests high female biological capacity for extreme endurance exercise.
1University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UNITED KINGDOM;
2Research & Clinical Innovation, Royal Centre for Defence Medicine, Lichfield, UNITED KINGDOM;
3Army Personnel Research Capability, Andover, UNITED KINGDOM;
4Performance, Nutrition and Dietetic Consulting, Birmingham, UNITED KINGDOM;
5MRC Centre for Reproductive Health, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UNITED KINGDOM;
6Faculty of Health and Life Sciences, Coventry University, Coventry, UNITED KINGDOM;
7Human Metabolic Research Unit, Universities of Coventry and Warwickshire NHS Trust and University of Warwick, Warwick, UNITED KINGDOM;
8Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM;
9Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, UNITED KINGDOM; and
10University of Newcastle, Newcastle upon Tyne, UNITED KINGDOM
Address for correspondence: Robert M. Gifford, M.B., Ch.B., University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, United Kingdom; E-mail: email@example.com.
R.M.R. and D.R.W. contributed equally as senior author.
Submitted for publication July 2018.
Accepted for publication October 2018.
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