{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T05:10:33Z","timestamp":1788844233213,"version":"build-2803163510"},"reference-count":40,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,9,6]],"date-time":"2026-09-06T00:00:00Z","timestamp":1788652800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003593","name":"CNPq","doi-asserted-by":"crossref","award":["# 309247\/2025-0"],"award-info":[{"award-number":["# 309247\/2025-0"]}],"id":[{"id":"10.13039\/501100003593","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/501100004586","name":"FAPERJ","doi-asserted-by":"crossref","award":["# E26\/201.247\/2021"],"award-info":[{"award-number":["# E26\/201.247\/2021"]}],"id":[{"id":"10.13039\/501100004586","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Brazilian Chamber of Deputies","award":["# n\u00b044890020"],"award-info":[{"award-number":["# n\u00b044890020"]}]},{"name":"Institutional Postdoctoral Programme","award":["#88887.239279\/2025-00)"],"award-info":[{"award-number":["#88887.239279\/2025-00)"]}]},{"DOI":"10.13039\/501100002322","name":"CAPES","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100002322","id-type":"DOI","asserted-by":"crossref"}]},{"id":[{"id":"https:\/\/ror.org\/00x0ma614","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Funct. Morphol. Kinesiol.","JFMK"],"abstract":"<jats:p>Background\/Objectives: Cardiac autonomic modulation, as assessed by heart rate variability (HRV), is a key indicator of physiological status. Although aging has traditionally been associated with reduced variability, morphological characteristics may be its main correlates. This study aimed to identify phenotypes of suppressed vagal modulation in women using a machine learning approach, specifically by correcting for HRV\u2019s intrinsic mathematical dependence on heart rate (HR). Methods: Seventy-five women (30\u201369 years old) were recruited during fitness center enrollment. To control for hormonal fluctuations, the younger cohort (30\u201349 years old) was assessed during the follicular phase, whereas the older cohort (50\u201369 years old) was postmenopausal. Electrocardiogram data for HRV, bioimpedance, and anthropometric measurements were collected. Intrinsic vagal modulation was isolated by adjusting root mean square of successive differences (RMSSD) for the mean R\u2013R interval (RMSSD_adj). The machine learning pipeline used LASSO for feature selection and multivariate logistic regression to identify suppressed vagal phenotypes (RMSSD_adj \u2264 0.0232). Model stability was verified using 1000 bootstrap iterations, and a cumulative Z-score index (ISCA) was used to characterize the morphologic\u2013hemodynamic burden. Results: LASSO identified central adiposity, measured by the waist-to-hip ratio, as the primary independent correlate of suppressed vagal phenotypes (RMSSD_adj \u2264 0.0232). The model achieved an area under the curve (AUC)\u2013ROC of 0.633 (95% CI: 0.490\u20130.771) with high specificity (0.900) and sensitivity of 0.360. No significant differences in intrinsic vagal modulation were observed between age cohorts (p &gt; 0.05). However, women classified as having a high morphologic\u2013hemodynamic burden (high-overload ISCA) exhibited a significantly higher resting heart rate, averaging 8.3 bpm more than the low-overload group (p &lt; 0.05), reflecting a higher physiological demand in this phenotype. Conclusions: The autonomic status of women is characterized more accurately by morphological phenotypes than by chronological age. Integrated kinanthropometric monitoring is essential for identifying reduced autonomic resilience regardless of birth year.<\/jats:p>","DOI":"10.3390\/jfmk11030355","type":"journal-article","created":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T10:30:46Z","timestamp":1788777046000},"page":"355","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Morphological Correlates of Suppressed Autonomic Modulation: A Machine Learning Approach to Identifying Vagal Impairment Phenotypes in Women"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9000-0201","authenticated-orcid":false,"given":"Wollner","family":"Materko","sequence":"first","affiliation":[{"name":"Biomedical Engineering Program (PEB), COPPE Institute, Universidade Federal do Rio de Janeiro, P.O. Box 68510, Rio de Janeiro 21941-972, RJ, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"given":"Gustavo Ferreira das","family":"Chagas","sequence":"additional","affiliation":[{"name":"Biomedical Engineering Program (PEB), COPPE Institute, Universidade Federal do Rio de Janeiro, P.O. Box 68510, Rio de Janeiro 21941-972, RJ, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4782-822X","authenticated-orcid":false,"given":"Paulo Roberto","family":"Benchimol-Barbosa","sequence":"additional","affiliation":[{"name":"Pedro Ernesto University Hospital, Universidade do Estado do Rio de Janeiro, Rio de Janeiro 20551-030, RJ, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3921-7787","authenticated-orcid":false,"given":"Jurandir","family":"Nadal","sequence":"additional","affiliation":[{"name":"Biomedical Engineering Program (PEB), COPPE Institute, Universidade Federal do Rio de Janeiro, P.O. Box 68510, Rio de Janeiro 21941-972, RJ, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Fields, A.D., Mohammadnabi, M.A., Fedewa, M.V., and Esco, M.R. (2025). Modified Stress Score and Sympathetic-Parasympathetic Ratio Using Ultra-Short-Term HRV in Athletes: A Novel Approach to Autonomic Monitoring. J. Funct. Morphol. Kinesiol., 10.","DOI":"10.3390\/jfmk10030310"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Couto, N.M.S., Bernal, J.V.M., Facioli, T.P., Dos Santos, D., and de Souza, H.C.D. (2026). 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