{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,14]],"date-time":"2026-05-14T22:24:22Z","timestamp":1778797462302,"version":"3.51.4"},"reference-count":35,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2016,5,11]],"date-time":"2016-05-11T00:00:00Z","timestamp":1462924800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Bioelectrical Impedance Spectroscopy (BIS) allows assessing the composition of body districts noninvasively and quickly, potentially providing important physiological\/clinical information. However, neither portable commercial instruments nor more advanced wearable prototypes simultaneously satisfy the demanding needs of unobtrusively tracking body fluid shifts in different segments simultaneously, over a broad frequency range, for long periods and with high measurements rate. These needs are often required to evaluate exercise tests in sports or rehabilitation medicine, or to assess gravitational stresses in aerospace medicine. Therefore, the aim of this work is to present a new wearable prototype for monitoring multi-segment and multi-frequency BIS unobtrusively over long periods. Our prototype guarantees low weight, small size and low power consumption. An analog board with current-injecting and voltage-sensing electrodes across three body segments interfaces a digital board that generates square-wave current stimuli and computes impedance at 10 frequencies from 1 to 796 kHz. To evaluate the information derivable from our device, we monitored the BIS of three body segments in a volunteer before, during and after physical exercise and postural shift. We show that it can describe the dynamics of exercise-induced changes and the effect of a sit-to-stand maneuver in active and inactive muscular districts separately and simultaneously.<\/jats:p>","DOI":"10.3390\/s16050673","type":"journal-article","created":{"date-parts":[[2016,5,11]],"date-time":"2016-05-11T05:25:41Z","timestamp":1462944341000},"page":"673","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["Wearable Multi-Frequency and Multi-Segment Bioelectrical Impedance Spectroscopy for Unobtrusively Tracking Body Fluid Shifts during Physical Activity in Real-Field Applications: A Preliminary Study"],"prefix":"10.3390","volume":"16","author":[{"given":"Federica","family":"Villa","sequence":"first","affiliation":[{"name":"Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan 20133, Italy"}]},{"given":"Alessandro","family":"Magnani","sequence":"additional","affiliation":[{"name":"Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan 20133, Italy"}]},{"given":"Martina","family":"Maggioni","sequence":"additional","affiliation":[{"name":"Center for Space Medicine and Extreme Environments, Charit\u00e9-University Medicine Berlin, Berlin 10117, Germany"},{"name":"Department of Biomedical Sciences for Health, Universit\u00e0 degli Studi di Milano, Milan 20133, Italy"}]},{"given":"Alexander","family":"Stahn","sequence":"additional","affiliation":[{"name":"Center for Space Medicine and Extreme Environments, Charit\u00e9-University Medicine Berlin, Berlin 10117, Germany"}]},{"given":"Susanna","family":"Rampichini","sequence":"additional","affiliation":[{"name":"Department of Biomedical Sciences for Health, Universit\u00e0 degli Studi di Milano, Milan 20133, Italy"}]},{"given":"Giampiero","family":"Merati","sequence":"additional","affiliation":[{"name":"Department of Biomedical Sciences for Health, Universit\u00e0 degli Studi di Milano, Milan 20133, Italy"},{"name":"IRCCS Fondazione Don C. Gnocchi, Milan 20148, Italy"}]},{"given":"Paolo","family":"Castiglioni","sequence":"additional","affiliation":[{"name":"IRCCS Fondazione Don C. Gnocchi, Milan 20148, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2016,5,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Preedy, V.R. (2012). Handbook of Anthropometry: Physical Measures of Human Form in Health and Disease, Springer Science+Business Media.","DOI":"10.1007\/978-1-4419-1788-1"},{"key":"ref_2","unstructured":"Sverre, G., and \u00d8rjan, G.M. (2008). Bioimpedance and Bioelectricity Basics, Elsevier Academic Press. [2nd ed.]."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1257","DOI":"10.1016\/j.medengphy.2008.06.009","article-title":"Body fluid volumes measurements by impedance: A review of bioimpedance spectroscopy (BIS) and bioimpedance analysis (BIA) methods","volume":"30","author":"Jaffrin","year":"2008","journal-title":"Med. Eng. 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