{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T01:08:24Z","timestamp":1792112904462,"version":"4.4.0"},"reference-count":35,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,2,20]],"date-time":"2025-02-20T00:00:00Z","timestamp":1740009600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Objectives\/Background: This study investigated the influence of acid\u2013base and electrolyte balance on the performance of female athletes in a 45 km ultramarathon. The aim was to analyze the impact of these variables on performance, particularly in athletes with varying completion times. Methods: Nineteen female athletes (mean age: 35.9 \u00b1 6.5 years) were divided into three groups based on their race completion times: faster, intermediate, and slower. Blood samples were collected before and after the race to assess biochemical variables and arterial blood gases. Results: Significant differences in potassium (K+) levels were found in the intermediate (p = 0.003, adjusted p = 0.01) and slower (p = 0.006, adjusted p = 0.03) groups. Hematocrit (Hct) showed a significant reduction in the intermediate group (p = 0.007, adjusted p = 0.04). In arterial blood gas variables, significant reductions in HCO3\u2212 and pCO2 were observed in the faster (HCO3\u2212: p = 0.002, adjusted p = 0.008; pCO2: p = 0.007, adjusted p = 0.02) and intermediate (HCO3\u2212: p = 0.005, adjusted p = 0.02) groups. In the slower group, significant reductions in pH (p = 0.001, adjusted p = 0.004) and HCO3\u2212 (p = 0.001, adjusted p = 0.004) were found. The correlation between post-race Na+ levels and performance was significant in the intermediate group (p = 0.01, adjusted p = 0.02). Conclusions: Acid\u2013base and electrolyte imbalances significantly affect ultramarathon performance, with a greater impact observed in athletes with slower times. These findings highlight the importance of strategies to optimize electrolyte and acid\u2013base balance in endurance events.<\/jats:p>","DOI":"10.3390\/nu17050751","type":"journal-article","created":{"date-parts":[[2025,2,21]],"date-time":"2025-02-21T07:53:06Z","timestamp":1740124386000},"page":"751","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Acid\u2013Base and Electrolyte Balance Responses in the Performance of Female Ultramarathon Runners in a 45 km Mountain Race"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8761-7171","authenticated-orcid":false,"given":"Marcelo Romanovitch","family":"Ribas","sequence":"first","affiliation":[{"name":"Postgraduate Program in Electrical Engineering and Industrial Informatics, Universidade Tecnol\u00f3gica Federal do Paran\u00e1, Curitiba 80230901, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Danieli Isabel Romanovitch","family":"Ribas","sequence":"additional","affiliation":[{"name":"Human Genetics Laboratory, Centro Universit\u00e1rio Aut\u00f4nomo do Brasil (UniBrasil), Curitiba 82821020, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Priscila","family":"Fernandes","sequence":"additional","affiliation":[{"name":"Postgraduate Program in Physical Education, Universidade Tecnol\u00f3gica Federal do Paran\u00e1, Curitiba 81310900, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4100-8765","authenticated-orcid":false,"given":"Georgian","family":"Badicu","sequence":"additional","affiliation":[{"name":"Department of Physical Education and Special Motricity, Faculty of Physical Education and Mountain Sports, Transilvania University of Bra\u015fov, 500068 Bra\u015fov, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8251-8000","authenticated-orcid":false,"given":"Elto","family":"Legnani","sequence":"additional","affiliation":[{"name":"Postgraduate Program in Physical Education, Universidade Tecnol\u00f3gica Federal do Paran\u00e1, Curitiba 81310900, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anderson Caetano","family":"Paulo","sequence":"additional","affiliation":[{"name":"Postgraduate Program in Physical Education, Universidade Tecnol\u00f3gica Federal do Paran\u00e1, Curitiba 81310900, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7677-5070","authenticated-orcid":false,"given":"Luca Paolo","family":"Ardig\u00f2","sequence":"additional","affiliation":[{"name":"Department of Teacher Education, NLA University College, 0166 Oslo, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6910-9077","authenticated-orcid":false,"given":"J\u00falio Cesar","family":"Bassan","sequence":"additional","affiliation":[{"name":"Postgraduate Program in Physical Education, Universidade Tecnol\u00f3gica Federal do Paran\u00e1, Curitiba 81310900, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"725","DOI":"10.1007\/s40279-021-01561-3","article-title":"Potential Long-Term Health Problems Associated with Ultra-Endurance Running: A Narrative Review","volume":"52","author":"Scheer","year":"2022","journal-title":"Sports Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1093\/icb\/icx069","article-title":"Physiological and Biomechanical Mechanisms of Distance Specific Human Running Performance","volume":"57","author":"Thompson","year":"2017","journal-title":"Integr. 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