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dc.contributor.advisorMorseth, Bente
dc.contributor.authorHeitmann, Kim Arne
dc.date.accessioned2023-03-01T21:53:59Z
dc.date.available2023-03-01T21:53:59Z
dc.date.issued2023-03-16
dc.description.abstractCurrent knowledge about the relationship between exercise and cardiac remodelling is mostly based on studies of athletes. Little is known about cardiac adaptations to moderate doses of exercise in the general adult and elderly population, and whether exercise-induced cardiac remodelling is a benign physiological adaption of exercise or part of a pathophysiological mechanism. The main objective of this thesis was to study the association between physical activity (PA) and the structure and function of the left side of the heart. Also, we wanted to explore if exercise-related left atrial (LA) remodelling was associated with adverse cardiac alterations and increased risk of incident atrial fibrillation (AF). In paper I, we applied a longitudinal design with repeated measures of self-reported PA and echocardiographic structural and functional data. In paper II, we applied a cross-sectional design to investigate the association between device-based PA and LA size. In paper III, we applied a prospective design to investigate the association between self-reported PA, LA size, and risk of AF. The main findings of this thesis are that exercise-induced cardiac remodelling also occurs with moderate levels of habitual PA, and not only in endurance-trained athletes. Moreover, our results indicate that exercise-induced LA remodelling is a benign physiological adaptation to exercise, without being associated with reduced left ventricular (LV) diastolic function or increased risk of incident AF. Higher levels of PA were associated with increased LA size in general, and increased LV size in females. However, no change in pump function or atrioventricular ratio at rest was observed with higher levels of PA. Moreover, moderate levels of habitual PA were associated with reduced risk of AF, and active individuals with LA enlargement did not have higher risk of AF than either active or inactive with normal LA size.en_US
dc.description.abstractNåværende kunnskap om sammenhengen mellom trening og hjerteremodellering er for det meste basert på studier av idrettsutøvere. Lite er kjent om hjertetilpasninger til moderate doser trening i den generelle voksne- og eldre befolkningen, og om treningsindusert hjertemodellering er en normal fysiologisk tilpasning til trening, eller en del av en patofysiologisk mekanisme. Dessuten er sammenhengen mellom fysisk aktivitet (FA), hjerteremodellering, og langtidsrisiko for atrieflimmer (AF) kompleks og representerer et kunskapshull, spesielt i den generelle voksen og eldre befolkningen. Hovedmålet med denne avhandlingen var å studere sammenhengen mellom FA og hjertets venstre sides struktur og funksjon. Vi ønsket også å undersøke om treningsrelatert remodellering av venstre atrium (VA) var assosiert med uønskede hjerteendringer og økt risiko for AF. I artikkel I brukte vi et longitudinelt design med gjentatte mål av selvrapportert FA og ekkokardiografiske strukturelle og funksjonelle data. I artikkel II brukte vi et tverrsnittsdesign for å undersøke sammenhengen mellom monitormålt FA og VA-størrelse. I artikkel III brukte vi et prospektivt design for å undersøke sammenhengen mellom selvrapportert FA, VA-størrelse og risiko for AF. Hovedfunnene i denne avhandlingen er at treningsindusert hjerteremodellering også forekommer ved moderate nivåer alminnelig FA, og ikke bare hos utholdehetsutøvere. Dessuten indikerer resultatene våre at treningsindusert VA-remodellering er en normal fysiologisk tilpasning til trening, uten å være assosiert med redusert venstre ventrikkel (VV) diastolisk funksjon eller økt risiko for insidens av AF. Høyere nivåer FA var assosiert med økt VA-størrelse generelt, og økt VVstørrelse hos kvinner. Imidlertid ble ingen endring i pumpefunksjon aller atrioventrikulært forhold i hvile observert ved høyere nivåer FA. Moderate nivåer FA var assosiert med redusert risiko for AF, og aktive individer med VA-forstørrelse hadde ikke høyere risiko for AF enn hverken aktive- eller inaktive med normal VA-størrelse.en_US
dc.description.doctoraltypeph.d.en_US
dc.description.popularabstractCurrent knowledge about cardiac adaptations to exercise is mostly based on studies of athletes. Little is known about cardiac adaptations to moderate doses of exercise in the general population, and whether changes in heart structure are a benign physiological adaption of exercise or part of a harmful mechanism. We wanted to study the association between physical activity (PA) and the structure and function of the left side of the heart, and explore if exercise-induced changes in heart structure were associated with increased risk of atrial fibrillation (AF). The project was based on data from the Tromsø Study. The main findings of this thesis are that changes in heart structure also occur with moderate levels of habitual PA, and not only in well-trained athletes, as previously shown. Moreover, our results indicate that cardiac adaptations to exercise in the general population are normal and harmless, without being associated with reduced pump function or increased risk of AF.en_US
dc.description.sponsorshipHelse Nord RHF (HNF1406-18)en_US
dc.identifier.urihttps://hdl.handle.net/10037/28634
dc.language.isoengen_US
dc.publisherUiT The Arctic University of Norwayen_US
dc.publisherUiT Norges arktiske universiteten_US
dc.relation.haspart<p>Paper I: Heitmann, K.A., Welde. B., Løchen, M.-L., Stylidis, M., Schirmer, H. & Morseth, B. (2022). Longitudinal associations between cumulative physical activity and change in structure and function of the left side of the heart: The Tromsø study 2007-2016. <i>Frontiers in Cardiovascular Medicine, 9</i>, 882077. Also available in Munin at <a href=https://hdl.handle.net/10037/26702>https://hdl.handle.net/10037/26702</a>. <p>Paper II: Heitmann, K.A., Løchen, M.-L., Hopstock, L.A., Stylidis, M., Welde, B., Schirmer, H. & Morseth, B. (2021). Cross-sectional associations between accelerometry-measured physical activity, left atrial size, and indices of left ventricular diastolic dysfunction: The Tromsø Study. <i>Preventive Medicine Reports, 21</i>, 101290. Also available in Munin at <a href=https://hdl.handle.net/10037/20289>https://hdl.handle.net/10037/20289</a>. <p>Paper III: Heitmann, K.A., Løchen, M.-L., Stylidis, M., Hopstock, L.A., Schirmer, H. & Morseth, B. (2022). Associations between physical activity, left atrial size and incident atrial fibrillation: the Tromsø Study 1994-2016. <i>Open Heart, 9</i>(1), e001823. Also available in Munin at <a href=https://hdl.handle.net/10037/24584>https://hdl.handle.net/10037/24584</a>.en_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2023 The Author(s)
dc.subject.courseIDDOKTOR-003
dc.subjectVDP::Medisinske Fag: 700::Helsefag: 800::Epidemiologi medisinsk og odontologisk statistikk: 803en_US
dc.subjectVDP::Medical disciplines: 700::Health sciences: 800::Epidemiology medical and dental statistics: 803en_US
dc.subjectVDP::Medisinske Fag: 700::Helsefag: 800::Forebyggende medisin: 804en_US
dc.subjectVDP::Medical disciplines: 700::Health sciences: 800::Preventive medicine: 804en_US
dc.subjectTromsøundersøkelsenen_US
dc.subjectThe Tromsø Studyen_US
dc.titlePhysical activity and the structure and function of the left side of the hearten_US
dc.typeDoctoral thesisen_US
dc.typeDoktorgradsavhandlingen_US


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