{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"omics_type":["Unknown"],"volume":["5"],"submitter":["Castellanos-Mendoza MC"],"pubmed_abstract":["<h4>Introduction</h4>The release of luteinising hormone (LH) before ovulation is disrupted during a state of low energy availability (EA). However, it remains unknown whether a threshold EA exists in athletic populations to trigger ovulatory disturbances (anovulation and luteal phase deficiency) as indicated by peak/mid-luteal serum progesterone concentration (Pk-PRG) during the menstrual cycle.<h4>Methods</h4>We assessed EA and Pk-PRG in 15 menstrual cycles to investigate the relationship between EA and Pk-PRG in free-living, competitive (trained-elite) Guatemalan racewalkers (<i>n </i>= 8) and runners (<i>n </i>= 7) [aged: 20 (14-41) years; post-menarche: 5 (2-26) years; height: 1.53 ± 0.09 m; mass: 49 ± 6 kg (41 ± 5 kg fat-free mass \"FFM\")]. EA was estimated over 7 consecutive days within the follicular phase using food, training, and physical activity diaries. A fasted blood sample was collected during the Pk-PRG period, 6-8 days after the LH peak, but before the final 2 days of each cycle. Serum progesterone concentration was quantified using electrochemiluminescence immunoassay.<h4>Results</h4>Participants that reported an EA of <35 kcal·kg FFM<sup>-1</sup>·day<sup>-1</sup> (<i>n </i>= 7) exhibited ovulatory disturbances (Pk-PRG ≤9.40 ng·mL<sup>-1</sup>). Athletes with EA ≥36 kcal·kg FFM<sup>-1</sup>·day<sup>-1</sup> (<i>n </i>= 8) recorded \"normal\"/\"potentially fertile\" cycles (Pk-PRG >9.40 ng·mL<sup>-1</sup>), except for a single racewalker with the lowest reported protein intake (1.1 g·kg body mass<sup>-1</sup>·day<sup>-1</sup>). EA was positively associated with Pk-PRG [<i>r</i>(9) = 0.79, 95% confidence interval (CI): 0.37-0.94; <i>p </i>= 0.003; 1 - <i>β</i> = 0.99] after excluding participants (<i>n </i>= 4) that likely under-reported/reduced their dietary intake.<h4>Conclusions</h4>The result from the linear regression analysis suggests that an EA ≥ 36 kcal·kg FFM<sup>-1</sup>·day<sup>-1</sup> is required to achieve \"normal ovulation.\" The threshold EA associated with ovulatory disturbances in athletes and non-invasive means of monitoring the ovulatory status warrant further research."],"journal":["Frontiers in sports and active living"],"pagination":["1279534"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC10690956"],"repository":["biostudies-literature"],"pubmed_title":["Free-living competitive racewalkers and runners with energy availability estimates of <35 kcal·kg fat-free mass<sup>-1</sup>·day<sup>-1</sup> exhibit peak serum progesterone concentrations indicative of ovulatory disturbances: a pilot study."],"pmcid":["PMC10690956"],"pubmed_authors":["Galloway SDR","Castellanos-Mendoza MC","Witard OC"],"additional_accession":[]},"is_claimable":false,"name":"Free-living competitive racewalkers and runners with energy availability estimates of <35 kcal·kg fat-free mass<sup>-1</sup>·day<sup>-1</sup> exhibit peak serum progesterone concentrations indicative of ovulatory disturbances: a pilot study.","description":"<h4>Introduction</h4>The release of luteinising hormone (LH) before ovulation is disrupted during a state of low energy availability (EA). However, it remains unknown whether a threshold EA exists in athletic populations to trigger ovulatory disturbances (anovulation and luteal phase deficiency) as indicated by peak/mid-luteal serum progesterone concentration (Pk-PRG) during the menstrual cycle.<h4>Methods</h4>We assessed EA and Pk-PRG in 15 menstrual cycles to investigate the relationship between EA and Pk-PRG in free-living, competitive (trained-elite) Guatemalan racewalkers (<i>n </i>= 8) and runners (<i>n </i>= 7) [aged: 20 (14-41) years; post-menarche: 5 (2-26) years; height: 1.53 ± 0.09 m; mass: 49 ± 6 kg (41 ± 5 kg fat-free mass \"FFM\")]. EA was estimated over 7 consecutive days within the follicular phase using food, training, and physical activity diaries. A fasted blood sample was collected during the Pk-PRG period, 6-8 days after the LH peak, but before the final 2 days of each cycle. Serum progesterone concentration was quantified using electrochemiluminescence immunoassay.<h4>Results</h4>Participants that reported an EA of <35 kcal·kg FFM<sup>-1</sup>·day<sup>-1</sup> (<i>n </i>= 7) exhibited ovulatory disturbances (Pk-PRG ≤9.40 ng·mL<sup>-1</sup>). Athletes with EA ≥36 kcal·kg FFM<sup>-1</sup>·day<sup>-1</sup> (<i>n </i>= 8) recorded \"normal\"/\"potentially fertile\" cycles (Pk-PRG >9.40 ng·mL<sup>-1</sup>), except for a single racewalker with the lowest reported protein intake (1.1 g·kg body mass<sup>-1</sup>·day<sup>-1</sup>). EA was positively associated with Pk-PRG [<i>r</i>(9) = 0.79, 95% confidence interval (CI): 0.37-0.94; <i>p </i>= 0.003; 1 - <i>β</i> = 0.99] after excluding participants (<i>n </i>= 4) that likely under-reported/reduced their dietary intake.<h4>Conclusions</h4>The result from the linear regression analysis suggests that an EA ≥ 36 kcal·kg FFM<sup>-1</sup>·day<sup>-1</sup> is required to achieve \"normal ovulation.\" The threshold EA associated with ovulatory disturbances in athletes and non-invasive means of monitoring the ovulatory status warrant further research.","dates":{"release":"2023-01-01T00:00:00Z","publication":"2023","modification":"2026-06-03T08:05:46.051Z","creation":"2026-04-26T03:11:17.973Z"},"accession":"S-EPMC10690956","cross_references":{"pubmed":["38046932"],"doi":["10.3389/fspor.2023.1279534"]}}