Author(s): SALMI, V., LEHTI, M.1, HACKNEY, A.C.2, IHALAINEN, J.K.1,3, MIKKONEN, R.1, Institution: UNIVERSITY OF JYVÄSKYLÄ, Country: FINLAND, Abstract-ID: 1973

INTRODUCTION:
Concentrations of sex steroid hormones, including androgens, fluctuate during the menstrual cycle (MC) and with hormonal contraceptive (HC) use [1]. However, research regarding the effects of chronic endurance training on basal androgen concentrations in females is limited. Therefore, we examined changes in androgen concentrations after ~8-week of a moderate intensity endurance training program (MIET).
METHODS:
Forty-four (tier 1) [2], naturally menstruating females (NM) [3] (length of MC 28 ± 4 d, age 30 ± 4 y, height 1.66 ± 0.05 m, weight 68.1 ± 10.8 kg, fat percentage 33.7 ± 8.3 %, and VO2max 38.4 ± 5.3 ml·kg-1·min-1) and 14 (tier 1) monophasic combined ethinyl estradiol-progestin containing oral contraceptive using females (OC) (age 27 ± 4 y, height 1.69 ± 0.06 m, weight 69.2 ± 5.9 kg, fat percentage 35.3 ± 5.1 %, and VO2max 39.0 ± 3.4 ml·kg-1·min-1) performed ~8-week MIET consisting of two MCs in NM and two 28-day HC “cycles” in OC. Prescribed training volume and intensity were the same in both groups and followed global exercise recommendations. Exercise included walking/running at 60–75 % of maximum heart rate. Fasting blood samples were collected before (PRE) and after (POST) MIET. In NM, samples were collected after the onset of bleeding between days 1–5 of the MC in the early follicular phase (FP) and 4–8 days after a positive ovulation test in the mid-luteal phase (LP). In OC, samples were collected between days 2–9 in the beginning of the active phase (i.e. pill taking days) and between days 2–6 of the inactive phase (i.e. pill free days). Estradiol (E2), progesterone (P4), total testosterone (tT), free testosterone (fT), dihydrotestosterone (DHT), androstenedione (A4), sex hormone-binding globulin (SHBG), dehydroepiandrosterone (DHEA) and its sulphate (DHEA-S) were analyzed from serum. Statistical analyses were conducted using generalized estimating equations.
RESULTS:
Ovulation was detected in 89 % of participants during the first MC and in 82 % of participants during the second MC of the ~8-week MIET. In NM, serum concentrations of fT were significantly lower at POST compared to PRE at FP (B = -0.37, p = 0.043). Concentrations of DHEA-S were significantly lower at POST compared to PRE at LP (B = -0.35, p = 0.029). In OC, concentrations of DHT were significantly lower at POST compared to PRE at the inactive phase (B = -89.25, p = 0.045). Concentrations of other androgens, as well as concentrations of E2, P4 and SHBG remained unchanged in both groups.
CONCLUSION:
Our findings suggest that chronic endurance training decreases androgen concentrations without concurrent changes in E2 and P4 both in naturally menstruating and monophasic combined oral contraceptive using females. However, the training induced reductions in specific androgenic hormones varied between NM and OC females.

References:
1. Salmi VM et al. (2024) in review.
2. McKay AKA et al. (2022) Int J Sports Physiol Perform. 17(2): 317–331.
3. Elliott-Sale KJ et al. (2021) Sports Med. 51(5): 843–861.