Female Reproductive, Adrenal, and Metabolic Changes during an Antarctic Traverse

• Published in: Medicine & Science in Sports & Exercise
• Main Authors: GIFFORD, ROBERT M., O’LEARY, THOMAS, COBB, RINN, BLACKADDER-WEINSTEIN, JODIE, DOUBLE, REBECCA, WARDLE, SOPHIE L., ANDERSON, RICHARD A., THAKE, C. DOUG, HATTERSLEY, JOHN, IMRAY, CHRISTOPHER H. E., WILSON, ADRIAN, GREEVES, JULIE P., REYNOLDS, REBECCA M., WOODS, DAVID R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Ovid Technologies (Wolters Kluwer Health) 2019
• Subjects: Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1249/mss.0000000000001803; https://journals.lww.com/00005768-201903000-00021

ABSTRACT Purpose To explore the effects of the first all-female transantarctic expedition on hormonal axes pertinent to reproductive and metabolic function. Methods 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). Results 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. Conclusions 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.