{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,25]],"date-time":"2026-07-25T22:15:14Z","timestamp":1785017714475,"version":"3.55.0"},"reference-count":57,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T00:00:00Z","timestamp":1776038400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Ultra-endurance sports like running over several hours or days exhibit great physical, psychological and metabolic strain on the respective athlete. Although the impact of ultramarathon running on the inflammatory\/immunological system gained interest in the last years, there is no study that examined the effect of different running distances on inflammatory\/immune system responses.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>During a non-stop ultramarathon, blood and saliva samples were collected before (Pre) and after the race (Post), and analyzed for changes in blood cell variables (immune cells leukocytes\/thrombocytes), cytokine response (pro- and anti-inflammation: IL-6\/IL-10\/IL-1ra\/IL1-beta\/TNF-alpha), and stress-related parameters (CRP as acute phase protein; uric acid for oxidative stress; cortisol\/kynurenine for general stress and energy metabolism). Biomarkers were supplemented by a stress-related questionnaire and 1) analyzed for the whole group of finishers (N\u00a0=\u00a043; 16f\/27m) and 2) compared between the respective running distances (100\/160.9\/230\u00a0km).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Leukocyte and thrombocyte count increased Post in all runners, with a more pronounced leukocyte response observed in 100\u00a0km vs. 160.9\u00a0km. IL-6\/IL-10\/IL-1ra increased Post in all sub-groups, whereas IL1-beta decreased only in the whole group. Stress\/immune response showed an increase of salivary cortisol and CRP in all runners. Sub-group analysis revealed highest cortisol and CRP concentrations in 230\u00a0km Post race.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Ultramarathons differ in the physiological strain they impose, with running distance being an important factor. Especially 100\u00a0km (faster pace, shorter duration) and 230\u00a0km (slower pace, longer duration) runners exhibited distinct inflammatory\/immunological responses. Thus, broad generalizations regarding the impact of a given ultramarathon on the immune system and potential post-race infection risk are unwarranted, and individualized guidance is currently more effective.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fimmu.2026.1799887","type":"journal-article","created":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T14:01:29Z","timestamp":1776088889000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["(Ultra-)inflammation or adaptation? Comparison of different ultramarathon distances and their effect on the immune system"],"prefix":"10.3389","volume":"17","author":[{"given":"Daniel A","family":"Bizjak","sequence":"first","affiliation":[{"name":"Department of Internal Medicine, Division of Sports and Rehabilitation Medicine, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lucas","family":"John","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Division of Sports and Rehabilitation Medicine, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Moritz","family":"Munk","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Division of Sports and Rehabilitation Medicine, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roman","family":"Bizjak","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Division of Sports and Rehabilitation Medicine, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jens","family":"Witzel","sequence":"additional","affiliation":[{"name":"Department of Central IT, Division Applications and Databases, University of Zurich","place":["Zurich, Switzerland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christoph","family":"Siebers","sequence":"additional","affiliation":[{"name":"Institute for Forensic Psychiatry and Sexual Research, University of Duisburg-Essen","place":["Essen, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sebastian V. W.","family":"Schulz","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Division of Sports and Rehabilitation Medicine, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Harald","family":"Engler","sequence":"additional","affiliation":[{"name":"Institute of Medical Psychology and Behavioral Immunobiology, Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, University of Duisburg-Essen","place":["Essen, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael","family":"Siebers","sequence":"additional","affiliation":[{"name":"Institute for Forensic Psychiatry and Sexual Research, University of Duisburg-Essen","place":["Essen, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Johannes","family":"Kirsten","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Division of Sports and Rehabilitation Medicine, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marijke","family":"Grau","sequence":"additional","affiliation":[{"name":"Institute of Cardiovascular Research and Sports Medicine, Molecular and Cellular Sports Medicine, German Sport University Cologne","place":["Cologne, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,4,13]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1123\/ijspp.7.4.310","article-title":"Ultramarathon runners: nature or nurture","volume":"7","author":"Knechtle","year":"2012","journal-title":"Int J Sports Physiol Perform"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.3390\/metabo12111138","article-title":"Running for your life: metabolic effects of a 160.9\/230 km non-stop ultramarathon race on body composition, inflammation, heart function, and nutritional parameters","volume":"12","author":"Bizjak","year":"2022","journal-title":"Metabolites"},{"key":"B3","doi-asserted-by":"publisher","first-page":"22","DOI":"10.1123\/tsp.2013-0008","article-title":"Exploring experiences of running an ultramarathon","volume":"28","author":"Holt","year":"2014","journal-title":"Sport Psychol"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1123\/tsp.2013-0064","article-title":"It\u2019s not about taking the easy road\u201d: the experiences of ultramarathon runners","volume":"28","author":"Simpson","year":"2014","journal-title":"Sport Psychol"},{"key":"B5","first-page":"6","article-title":"Position statement part one: immune function and exercise","volume":"17","author":"Walsh","year":"2011","journal-title":"Exerc Immunol Rev"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-0838.2011.01422.x","article-title":"Influence of training load on upper respiratory tract infection incidence and antigen-stimulated cytokine production","volume":"23","author":"Gleeson","year":"2013","journal-title":"Scand J Med Sci Sports"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.2165\/00007256-200737040-00036","article-title":"Marathon training and immune function","volume":"37","author":"Nieman","year":"2007","journal-title":"Sports Med"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2018.00634","article-title":"Physiology and pathophysiology in ultra-marathon running","volume":"9","author":"Knechtle","year":"2018","journal-title":"Front Physiol"},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.23736\/S0022-4707.20.11150-2","article-title":"Changes in immunological parameters in ultramarathon runners depending on the duration of the load","volume":"61","author":"Plakida","year":"2021","journal-title":"J Sports Med Phys Fitness"},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2017.00638","article-title":"The effect of a 100-km ultra-marathon under freezing conditions on selected immunological and hematological parameters","volume":"8","author":"\u017d\u00e1kovsk\u00e1","year":"2017","journal-title":"Front Physiol"},{"key":"B11","doi-asserted-by":"publisher","DOI":"10.1111\/apha.12898","article-title":"Adaptations to endurance training depend on exercise-induced oxidative stress: exploiting redox interindividual variability","volume":"222","author":"Margaritelis","year":"2018","journal-title":"Acta Physiol (Oxf)"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.1186\/s40798-025-00810-3","article-title":"Physiology and pathophysiology of marathon running: a narrative review","volume":"11","author":"Braschler","year":"2025","journal-title":"Sports Med - 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