{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T11:07:00Z","timestamp":1789556820865,"version":"build-2803163510"},"reference-count":26,"publisher":"BMJ","issue":"2","license":[{"start":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T00:00:00Z","timestamp":1784592000000},"content-version":"unspecified","delay-in-days":20,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["Open Heart"],"accepted":{"date-parts":[[2026,7,4]]},"published-print":{"date-parts":[[2026,7]]},"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>This study assessed cardiac performance in response to maximal physiological stress in recreational long-distance runners.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>In this cross-sectional observational study, 44 male recreational long-distance runners (age 32.6\u00b18.8 years; body mass index 23.4\u00b12.2\u2009kg\/m\u00b2) and 41 age-matched and sex-matched untrained controls performed a maximal cardiopulmonary exercise test on a cycle ergometer. Gas exchange and haemodynamic (bioreactance) measurements were assessed simultaneously. Cardiac power output (CPO), an integrative index of cardiac performance, was calculated from cardiac output and mean arterial pressure. Oxygen extraction was expressed as the arterial-venous oxygen difference (a\u2013vO\u2082 diff).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Runners achieved significantly higher maximal oxygen consumption than controls (53.2\u00b16.8 vs 38.7\u00b18.2\u2009mL\u00b7kg\u207b\u00b9\u00b7min\u207b\u00b9, p&lt;0.01) and higher peak work rate (276\u00b131 vs 231\u00b160 W, p&lt;0.01). Despite superior aerobic capacity, runners demonstrated lower indices of cardiac performance at maximal exercise, including CPO (5.01\u00b11.00 vs 5.64\u00b11.46 W, p=0.03), cardiac output (18.7\u00b13.0 vs 22.6\u00b14.4\u2009L\u00b7min\u207b\u00b9, p&lt;0.01) and stroke volume (109\u00b121 vs 126\u00b128\u2009mL\u00b7beat\u207b\u00b9, p=0.04). In contrast, a\u2013vO\u2082 diff was approximately 30% higher in runners (21.6\u00b13.7 vs 15.9\u00b14.5\u2009mL O\u2082\u00b7100\u2009mL\u207b\u00b9 blood, p&lt;0.01).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Long-distance runners demonstrate higher oxygen consumption and oxygen extraction but lower haemodynamic response to maximal exercise stress test. These findings may suggest a potential cardioprotective role of endurance training characterised by reduced cardiac workload during maximal physiological stress.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/openhrt-2026-004263","type":"journal-article","created":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T13:35:49Z","timestamp":1784640949000},"page":"e004263","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Reduced cardiac workload and enhanced oxygen extraction during maximal exercise in recreational endurance runners"],"prefix":"10.1136","volume":"13","author":[{"given":"Anastasija","family":"Kocic","sequence":"first","affiliation":[{"name":"Faculty of Sport and Physical Education, University of Belgrade, Belgrade, Serbia"},{"name":"Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ljubica","family":"Ristanovic","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, University of Belgrade, Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sanja","family":"Mirkovic","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, University of Belgrade, Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marija","family":"Macura","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, University of Belgrade, Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stefan","family":"Seman","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, University of Belgrade, Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vladimir","family":"Ilic","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, University of Belgrade, Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dragana","family":"Labudovic","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, University of Belgrade, Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vladimir","family":"Mrdakovic","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, University of Belgrade, Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sa\u0161a","family":"Jakovljevic","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, University of Belgrade, Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sa\u0161a","family":"Bubanj","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, Univerzitet u Nisu, Ni\u0161, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nduka Charles","family":"Okwose","sequence":"additional","affiliation":[{"name":"Coventry University, Coventry, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2686-6542","authenticated-orcid":false,"given":"Djordje","family":"Jakovljevic","sequence":"additional","affiliation":[{"name":"Cardiovascular and Translational Medicine, Coventry University, Coventry, UK"},{"name":"Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stanimir","family":"Stojiljkovic","sequence":"additional","affiliation":[{"name":"Faculty of Sport and Physical Education, 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