{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,8]],"date-time":"2026-03-08T22:47:24Z","timestamp":1773010044297,"version":"3.50.1"},"reference-count":54,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2025,7,20]],"date-time":"2025-07-20T00:00:00Z","timestamp":1752969600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2025,7,20]],"date-time":"2025-07-20T00:00:00Z","timestamp":1752969600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["physoc.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Experimental Physiology"],"published-print":{"date-parts":[[2026,3]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    Following an acute infection with severe acute respiratory syndrome coronavirus 2 (SARS\u2010CoV\u20102), a substantial percentage of patients report the persistence of debilitating symptoms, often grouped in a syndrome termed \u2018long COVID\u2019. We sought to identify potential pathophysiological mechanisms responsible for the persistence, in some long COVID patients, of symptoms related to fatigue\/exercise intolerance (excessive or early fatigue, excessive or early dyspnoea, muscle weakness, and myalgias) more than 2\u00a0years after the original infection. Twelve patients who reported persistent symptoms (Long COVID group; 57\u00a0\u00b1\u00a06 years, mean\u00a0\u00b1\u00a0SD), and 14 patients without the symptoms (Control group; 57\u00a0\u00b1\u00a08\u00a0years) were evaluated. An extensive series of measurements were performed to identify pathophysiological mechanisms potentially responsible for the symptoms. In long COVID patients, all items evaluating quality of life (SF\u201036 questionnaire) had lower scores (\n                    <jats:italic>P\u00a0<\/jats:italic>\n                    &lt;\u00a00.01) compared to control. The habitual level of physical activity, muscle size and strength, maximal aerobic power and the ventilatory thresholds, peak cardiac function, the mechanical efficiency of cycling, pulmonary  kinetics, microvascular\/endothelial function (hyperemic response in the common femoral artery during passive leg movements), skeletal muscle oxidative metabolism (peak fractional O\n                    <jats:sub>2<\/jats:sub>\n                    extraction and muscle  recovery kinetics by the repeated occlusions test, by near\u2010infrared spectroscopy) were not different in the two groups. Evidence of ventilatory inefficiency was described in a subgroup of long COVID patients. More than 2\u00a0years after the original SARS\u2010CoV\u20102 infection, a discrepancy was observed between the persistence of debilitating symptoms of fatigue\/exercise intolerance and the absence of several investigated pathophysiological mechanisms. The discrepancy may be due to factors that remain to be elucidated.\n                  <\/jats:p>","DOI":"10.1113\/ep092850","type":"journal-article","created":{"date-parts":[[2025,7,20]],"date-time":"2025-07-20T12:13:47Z","timestamp":1753013627000},"page":"1413-1428","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Persistence of fatigue in the absence of pathophysiological mechanisms in some patients more than 2 years after the original SARS\u2010CoV\u20102 infection"],"prefix":"10.1113","volume":"111","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4182-9216","authenticated-orcid":false,"given":"Giovanni","family":"Baldassarre","sequence":"first","affiliation":[{"name":"Department of Medicine (DMED) University of Udine  Udine Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lucrezia","family":"Zuccarelli","sequence":"additional","affiliation":[{"name":"Department of Medicine (DMED) University of Udine  Udine Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thomas","family":"Favaretto","sequence":"additional","affiliation":[{"name":"Department of Medicine (DMED) University of Udine  Udine Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-4645-1242","authenticated-orcid":false,"given":"Caterina","family":"Ursella","sequence":"additional","affiliation":[{"name":"Department of Medicine (DMED) University of Udine  Udine Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andrea","family":"Palomba","sequence":"additional","affiliation":[{"name":"Department of Medicine (DMED) University of Udine  Udine Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paulo Cesar do Nascimento","family":"Salvador","sequence":"additional","affiliation":[{"name":"Department of Medicine (DMED) University of Udine  Udine Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Emanuela","family":"Sozio","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases Azienda Sanitaria Universitaria Friuli Centrale (ASUFC)  Udine Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ernesto","family":"Crisafulli","sequence":"additional","affiliation":[{"name":"Department of Medicine University of Verona  Verona Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Massimo","family":"Imazio","sequence":"additional","affiliation":[{"name":"Department of Medicine (DMED) University of Udine  Udine Italy"},{"name":"Cardiothoracic Department Azienda Sanitaria Universitaria Friuli Centrale (ASUFC)  Udine Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Carlo","family":"Tascini","sequence":"additional","affiliation":[{"name":"Department of Medicine (DMED) University of Udine  Udine Italy"},{"name":"Division of Infectious Diseases Azienda Sanitaria Universitaria Friuli Centrale (ASUFC)  Udine Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3188-1659","authenticated-orcid":false,"given":"Bruno","family":"Grassi","sequence":"additional","affiliation":[{"name":"Department of Medicine (DMED) University of Udine  Udine Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,7,20]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1985.sp015794"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.3390\/jcm10122591"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-023-44432-3"},{"key":"e_1_2_9_5_1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00710.2020"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1986.60.6.2020"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00421-024-05652-7"},{"key":"e_1_2_9_8_1","doi-asserted-by":"publisher","DOI":"10.1001\/jama.1989.03430170057028"},{"issue":"2","key":"e_1_2_9_9_1","first-page":"90","article-title":"Perceived exertion: A note on \u201chistory\u201d and methods","volume":"5","author":"Borg G. 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