{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T14:34:52Z","timestamp":1790778892668,"version":"4.1.0"},"reference-count":41,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2023,4,27]],"date-time":"2023-04-27T00:00:00Z","timestamp":1682553600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Scandinavian Med Sci Sports"],"published-print":{"date-parts":[[2023,8]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Background<\/jats:title><jats:p>The optimal allocation of training time to different intensities in cardiac rehabilitation is still under debate. The objective of this study was to explore whether in a 12\u2010week cardiac rehabilitation program, replacement of two of four usual continuous endurance training (CET) sessions per week with energy expenditure\u2010matched high\u2010intensity interval training (HIIT) affects the trajectories of cardiopulmonary exercise test (CPET) variables such as ventilatory equivalents for O<jats:sub>2<\/jats:sub> (EqO<jats:sub>2<\/jats:sub>) and CO<jats:sub>2<\/jats:sub> (EqCO<jats:sub>2<\/jats:sub>), and blood lactate (BLa) during CPET.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Eighty\u2010two male patients undergoing outpatient cardiac rehabilitation after an acute coronary syndrome were randomized to CET (age [mean\u2009\u00b1\u2009SD] 61.7\u2009\u00b1\u20099.8\u2009years, body mass index [BMI] 28.1\u2009\u00b1\u20093.4) or HIIT+CET (60.0\u2009\u00b1\u20099.4\u2009years, BMI 28.5\u2009\u00b1\u20093.5). CPET was performed at baseline, after 6 and after 12\u2009weeks. HIIT consisted of ten 60\u2010s bouts of cycling at an intensity of 100% of the maximal power output (<jats:italic>P<\/jats:italic><jats:sub>max<\/jats:sub>) achieved in an incremental test to exhaustion, interspersed with 60\u2009s at 20% <jats:italic>P<\/jats:italic><jats:sub>max<\/jats:sub>. CET was performed at 60% <jats:italic>P<\/jats:italic><jats:sub>max<\/jats:sub> with equal duration. Training intensities were adjusted after 6\u2009weeks to account for the training\u2010induced improvement in cardiorespiratory fitness. The entire functions defining the relationship between EqO<jats:sub>2<\/jats:sub>, EqCO<jats:sub>2<\/jats:sub>, and BLa, with power output were modeled using linear mixed models to assess how these trajectories are affected by HIIT.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>After 6 and 12\u2009weeks, <jats:italic>P<\/jats:italic><jats:sub>max<\/jats:sub> increased to 112.9% and 117.5% of baseline after CET, and to 113.9% and 124.7% after HIIT+CET (means). Twelve weeks of HIIT+CET elicited greater reductions of EqO<jats:sub>2<\/jats:sub> and EqCO<jats:sub>2<\/jats:sub> than CET alone (<jats:italic>p<\/jats:italic>\u2009&lt;\u20090.0001 each) in a range above 100% baseline <jats:italic>P<\/jats:italic><jats:sub>max<\/jats:sub>. Specifically, at 100% of baseline <jats:italic>P<\/jats:italic><jats:sub>max<\/jats:sub>, least squares arithmetic mean EqO<jats:sub>2<\/jats:sub> values of CET and HIIT+CET patients were 36.2 versus 33.5. At 115% and 130% of baseline <jats:italic>P<\/jats:italic><jats:sub>max<\/jats:sub>, EqO<jats:sub>2<\/jats:sub> values were 41.2 versus 37.1 and 47.2 versus 41.7. Similarly, corresponding EqCO<jats:sub>2<\/jats:sub> values of CET and HIIT+CET patients were 32.4 versus 31.0, 34.3 versus 32.2, and 37.0 versus 34.0. Conversely, mean BLa levels (mM) were not differently affected (<jats:italic>p<\/jats:italic>\u2009=\u20090.64). At 100%, 115%, and 130% of baseline <jats:italic>P<\/jats:italic><jats:sub>max<\/jats:sub> after 12\u2009weeks, BLa levels did not differ to a relevant extent (least squares geometric means, 3.56 vs. 3.63, 5.59 vs. 5.61, 9.27 vs. 9.10).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>While HIIT+CET reduced ventilatory equivalents more effectively than CET alone, specifically when patients were approaching their maximal performance during CPET, both training strategies were equally effective in reducing BLa levels.<\/jats:p><\/jats:sec>","DOI":"10.1111\/sms.14380","type":"journal-article","created":{"date-parts":[[2023,4,28]],"date-time":"2023-04-28T06:56:36Z","timestamp":1682664996000},"page":"1345-1359","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Effects of high\u2010intensity interval training on trajectories of gas\u2010exchange measures and blood lactate concentrations during cardiopulmonary exercise tests in cardiac rehabilitation\u2014A randomized controlled trial"],"prefix":"10.1111","volume":"33","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3398-0442","authenticated-orcid":false,"given":"Stefan","family":"Heber","sequence":"first","affiliation":[{"name":"Institute of Physiology, Center for Physiology and Pharmacology Medical University of Vienna  Vienna Austria"},{"name":"Institute of Sport Science, Center for Sport Science and University Sports University of Vienna  Vienna Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andreas","family":"Gleiss","sequence":"additional","affiliation":[{"name":"Institute of Clinical Biometrics, Center for Medical Data Science Medical University of Vienna  Vienna Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marina","family":"Kuzdas\u2010Sallaberger","sequence":"additional","affiliation":[{"name":"Cardiomed Center for Outpatient Cardiac Rehabilitation  Linz Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Hausharter","sequence":"additional","affiliation":[{"name":"Institute of Physiology, Center for Physiology and Pharmacology Medical University of Vienna  Vienna Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Melanie","family":"Matousek","sequence":"additional","affiliation":[{"name":"Institute of Sport Science, Center for Sport Science and University Sports University of Vienna  Vienna Austria"},{"name":"Karl\u2010Landsteiner University of Health Sciences  Krems Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helmuth","family":"Ocenasek","sequence":"additional","affiliation":[{"name":"Cardiomed Center for Outpatient Cardiac Rehabilitation  Linz Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Beatrix","family":"Fischer","sequence":"additional","affiliation":[{"name":"Institute of Physiology, Center for Physiology and 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