Author(s): MIKKONEN, R., WYNNE-ELLIS, M., IHALAINEN, J., Institution: UNIVERSITY OF JYVÄSKYLÄ, Country: FINLAND, Abstract-ID: 2107

INTRODUCTION:
Low energy availability (LEA) has been recognized as a challenge for physically active and athletic individuals [1] as well as military service personnel [2]. LEA is defined as a mismatch between dietary energy intake to cover energy expenditure due to physical activity and/or exercise that results in a decrease in energy availability (EA) for physiological processes that maintain athlete health and support training adaptations [3]. A relatively common sign of LEA in females not using hormonal contraceptives (HC) is hormonal dysfunction manifested as menstrual disturbances that can range from subclinical disturbances such as anovulation or an “inadequate” luteal phase to clinically more concerning oligomenorrhea/amenorrhea, which is recognized as a severe primary indicator/primary indicator of relative energy deficiency in sport (REDs). Several other hormonal indicators of LEA/REDs have been identified including: sub-clinically or clinically low total or free T3, sub-clinically or clinically low IGF-1, and elevated resting or 24-hour urine cortisol [4].
Approximately half of the female athletic population and approximately two-thirds of female military service personnel [5,6] are HC users. HC use may alter hormonal milieu beyond their intended target of reproductive hormones. Importantly, HC users are not immune to problems associated with under-fueling, overtraining, and psychological stress but the hormonal cycles of HC users may be masked rendering this severe primary indicator/ primary indicator of REDs unusable in this population.
METHODS:
Cross-sectional data from the NoREDS (Athletic Performance and Nutrition) three-year follow-up study, comprising 146 national- to international-level female athletes was analyzed.
RESULTS:
IGF-1 concentrations were lower in HC users than in naturally menstruating females, cortisol levels were higher in HC users than in in naturally menstruating females, and that triiodothyronine (T3) concentrations were higher in HC users than in naturally menstruating females.
CONCLUSION:
These results combined with published longitudinal data indicating similar trends and confirmed LEA in naturally menstruating females, combined HC users and progestin-only HC users [7] have led to the hypothesis that HC use and LEA both independently and synergistically alter hormone concentrations. Increasing knowledge regarding the effect of hormonal contraceptives on exercise performance and indicators associated with LEA and REDs is essential. Many women need/desire hormonal contraceptives to support their menstrual health and overall health thus considering this population (and sub-populations) in their research has relevance for sport and exercise, performance and aspects of well-being.

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