The effects of an ultra-endurance event on heart rate variability and cognitive performance during induced stress in Ironman triathletes

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dc.contributor.advisorDerman, Wayneen_ZA
dc.contributor.authorJoubert, Ilseen_ZA
dc.date.accessioned2014-07-28T08:23:38Z
dc.date.available2014-07-28T08:23:38Z
dc.date.issued2009en_ZA
dc.descriptionIncludes abstract.
dc.descriptionIncludes bibliographical references (leaves 55-79).
dc.description.abstractThe effects of long-term participation in ultra-endurance exercise on the cardiovascular system have recently been the subject of much interest. It is well known that HRV, a marker of autonomic activity, is enhanced with long-term aerobic exercise training. However, after acute exercise, HRV is reduced, but recovers over time depending on the intensity of the prior bout of exercise. A limitation of previous research is that exercise bouts of only up to 120 minutes have been studied. A modified Stroop Task is a laboratory stressor to assess executive cognitive function by means of reaction time and accuracy. The resting HRV is directly related to these prefrontal neural functions, but the effect of an altered HRV on cognitive function has never been investigated. We determined the effects of an ultra duration (10 – 15 hours) exercise event on parameters of HRV and cognitive function during a Modified Stroop Task, 60 – 200 minutes after the 2007 South African Ironman Triathlon event (3,6km swim; 180 Km cycle; 42,2 Km run). 1 Female and 13 male competing triathletes (IRON; ages 33.7±7.9) and 7 control subjects (CON; 2 female and 5 males aged 42 ±4.5) completed a Modified Stroop Task before and after the event. The individual HRV parameters, heart rate (HR), respiratory frequency (RF), reaction time (RT) and % of mistakes made were recorded via the Biopac MP150WSW System (Goletta, California, USA). Data was transformed by auto regressive analyses (Biomedical signal analysis group, University of Kuopio, Finland) into LF (0.04 - 0.15 Hz) and HF (0.15 - 0.5 Hz) components. Additional calculations included %LF and %HF as well as the central or peak frequencies in both the LF and HF bands.en_ZA
dc.identifier.apacitationJoubert, I. (2009). <i>The effects of an ultra-endurance event on heart rate variability and cognitive performance during induced stress in Ironman triathletes</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,MRC/UCT RU for Exercise and Sport Medicine. Retrieved from http://hdl.handle.net/11427/2754en_ZA
dc.identifier.chicagocitationJoubert, Ilse. <i>"The effects of an ultra-endurance event on heart rate variability and cognitive performance during induced stress in Ironman triathletes."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,MRC/UCT RU for Exercise and Sport Medicine, 2009. http://hdl.handle.net/11427/2754en_ZA
dc.identifier.citationJoubert, I. 2009. The effects of an ultra-endurance event on heart rate variability and cognitive performance during induced stress in Ironman triathletes. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Joubert, Ilse AB - The effects of long-term participation in ultra-endurance exercise on the cardiovascular system have recently been the subject of much interest. It is well known that HRV, a marker of autonomic activity, is enhanced with long-term aerobic exercise training. However, after acute exercise, HRV is reduced, but recovers over time depending on the intensity of the prior bout of exercise. A limitation of previous research is that exercise bouts of only up to 120 minutes have been studied. A modified Stroop Task is a laboratory stressor to assess executive cognitive function by means of reaction time and accuracy. The resting HRV is directly related to these prefrontal neural functions, but the effect of an altered HRV on cognitive function has never been investigated. We determined the effects of an ultra duration (10 – 15 hours) exercise event on parameters of HRV and cognitive function during a Modified Stroop Task, 60 – 200 minutes after the 2007 South African Ironman Triathlon event (3,6km swim; 180 Km cycle; 42,2 Km run). 1 Female and 13 male competing triathletes (IRON; ages 33.7±7.9) and 7 control subjects (CON; 2 female and 5 males aged 42 ±4.5) completed a Modified Stroop Task before and after the event. The individual HRV parameters, heart rate (HR), respiratory frequency (RF), reaction time (RT) and % of mistakes made were recorded via the Biopac MP150WSW System (Goletta, California, USA). Data was transformed by auto regressive analyses (Biomedical signal analysis group, University of Kuopio, Finland) into LF (0.04 - 0.15 Hz) and HF (0.15 - 0.5 Hz) components. Additional calculations included %LF and %HF as well as the central or peak frequencies in both the LF and HF bands. DA - 2009 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2009 T1 - The effects of an ultra-endurance event on heart rate variability and cognitive performance during induced stress in Ironman triathletes TI - The effects of an ultra-endurance event on heart rate variability and cognitive performance during induced stress in Ironman triathletes UR - http://hdl.handle.net/11427/2754 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/2754
dc.identifier.vancouvercitationJoubert I. The effects of an ultra-endurance event on heart rate variability and cognitive performance during induced stress in Ironman triathletes. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,MRC/UCT RU for Exercise and Sport Medicine, 2009 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/2754en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentMRC/UCT RU for Exercise and Sport Medicineen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherSports Medicineen_ZA
dc.titleThe effects of an ultra-endurance event on heart rate variability and cognitive performance during induced stress in Ironman triathletesen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMPhilen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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