Kari Nytrøen

  • Postdoctoral research fellow, PhD, M.Sc

Kari Nytrøen successfully defended her thesis "Chronotropic responses and effect of high intensity interval based aerobic exercise in heart transplant recipients." in February 2014.

Physiotherapist and doctoral candidate Kari Nytrøen found that high-intensity interval training is a safe and effective form of exercise that improves stamina, enduring muscle strength and overall health in stable heart transplant patients.

Interval training is known for its positive effects. Nytrøen and co-workers wanted to investigate whether interval training has the same good effect among heart transplant patients as it has in the rest of the population. This type of exercise has been considered "unphysiologic" for heart transplant patients as they lack nerve supply to the new heart, leading to reduced heart rate response.

In this thesis it was shown that the heart rate response is partially normalized in most patients one year after transplantation and that the interval training performed by patients on average 4 years after transplantation led to:
- Increased oxygen uptake / better fitness (13% increase)
- Increased endurance of muscle strength (17% increase)  
- Better quality of life  
- Decreased progression (> 50%) of vasculopathy (a special form of arteriosclerosis affecting cardiac transplant patients = cardiac allograft vasculopathy)  

In conclusion, interval training is a safe and effective form of exercise that is recommended to improve the fitness and health of all heart transplant recipients well in way in the recovery process, given that their condition has remained stable and that they are othervise healthy. In addition to improved fitness and enduring muscle strength, interval training slows the development of vasculopathy, which may lead to reduced morbidity and mortality in this patient population.


Publications 2020

Kienlin S, Nytrøen K, Stacey D, Kasper J (2020)
Ready for shared decision making: Pretesting a training module for health professionals on sharing decisions with their patients
J Eval Clin Pract, 26 (2), 610-621
DOI 10.1111/jep.13380, PubMed 32114700

Nytrøen K, Rolid K, Yardley M, Gullestad L (2020)
Effect of high-intensity interval training in young heart transplant recipients: results from two randomized controlled trials
BMC Sports Sci Med Rehabil, 12, 35
DOI 10.1186/s13102-020-00180-1, PubMed 32518655

Rolid K, Andreassen AK, Yardley M, Gude E, Bjørkelund E, Authen AR, Grov I, Broch K, Gullestad L, Nytrøen K (2020)
Long-term effects of high-intensity training vs moderate intensity training in heart transplant recipients: A 3-year follow-up study of the randomized-controlled HITTS study
Am J Transplant
DOI 10.1111/ajt.16087, PubMed 32484261

Rolid K, Andreassen AK, Yardley M, Gude E, Bjørkelund E, Authen AR, Grov I, Pettersen KI, Dall CH, Karason K, Broch K, Gullestad L, Nytrøen K (2020)
High-intensity interval training and health-related quality of life in de novo heart transplant recipients - results from a randomized controlled trial
Health Qual Life Outcomes, 18 (1), 283
DOI 10.1186/s12955-020-01536-4, PubMed 32807179

Publications 2019

Nygaard S, Christensen AH, Rolid K, Nytrøen K, Gullestad L, Fiane A, Thaulow E, Døhlen G, Godang K, Saul JP, Wyller VBB (2019)
Autonomic cardiovascular control changes in recent heart transplant recipients lead to physiological limitations in response to orthostatic challenge and isometric exercise
Eur J Appl Physiol, 119 (10), 2225-2236
DOI 10.1007/s00421-019-04207-5, PubMed 31407088

Nytrøen K, Rolid K, Andreassen AK, Yardley M, Gude E, Dahle DO, Bjørkelund E, Relbo Authen A, Grov I, Philip Wigh J, Have Dall C, Gustafsson F, Karason K, Gullestad L (2019)
Effect of High-Intensity Interval Training in De Novo Heart Transplant Recipients in Scandinavia
Circulation, 139 (19), 2198-2211
DOI 10.1161/CIRCULATIONAHA.118.036747, PubMed 30773030

Nytrøen K, Rolid K, Gullestad L (2019)
Response by Nytrøen et al to Letter Regarding Article, "Effect of High-Intensity Interval Training in De Novo Heart Transplant Recipients in Scandinavia"
Circulation, 140 (17), e735-e736
DOI 10.1161/CIRCULATIONAHA.119.042458, PubMed 31634012

Publications 2018

Eiring Ø, Brurberg KG, Nytrøen K, Nylenna M (2018)
Rapid methods including network meta-analysis to produce evidence in clinical decision support: a decision analysis
Syst Rev, 7 (1), 168
DOI 10.1186/s13643-018-0829-z, PubMed 30342549

Rolid K, Andreassen AK, Yardley M, Bjørkelund E, Karason K, Wigh JP, Dall CH, Gustafsson F, Gullestad L, Nytrøen K (2018)
Clinical features and determinants of VO2peak in de novo heart transplant recipients
World J Transplant, 8 (5), 188-197
DOI 10.5500/wjt.v8.i5.188, PubMed 30211027

Yardley M, Gullestad L, Nytrøen K (2018)
Importance of physical capacity and the effects of exercise in heart transplant recipients
World J Transplant, 8 (1), 1-12
DOI 10.5500/wjt.v8.i1.1, PubMed 29507857

Publications 2017

Eiring Ø, Nytrøen K, Kienlin S, Khodambashi S, Nylenna M (2017)
The development and feasibility of a personal health-optimization system for people with bipolar disorder
BMC Med Inform Decis Mak, 17 (1), 102
DOI 10.1186/s12911-017-0481-x, PubMed 28693482

Yardley M, Ueland T, Aukrust P, Michelsen A, Bjørkelund E, Gullestad L, Nytrøen K (2017)
Immediate response in markers of inflammation and angiogenesis during exercise: a randomised cross-over study in heart transplant recipients
Open Heart, 4 (2), e000635
DOI 10.1136/openhrt-2017-000635, PubMed 29225901

Publications 2016

Eiring Ø, Nylenna M, Nytrøen K (2016)
Patient-Important Outcomes in the Long-Term Treatment of Bipolar Disorder: A Mixed-Methods Approach Investigating Relative Preferences and a Proposed Taxonomy
Patient, 9 (2), 91-102
DOI 10.1007/s40271-015-0128-x, PubMed 25990222

Yardley M, Gullestad L, Bendz B, Bjørkelund E, Rolid K, Arora S, Nytrøen K (2016)
Long-term effects of high-intensity interval training in heart transplant recipients: A 5-year follow-up study of a randomized controlled trial
Clin Transplant, 31 (1)
DOI 10.1111/ctr.12868, PubMed 27865004

Publications 2015

Eiring Ø, Landmark BF, Aas E, Salkeld G, Nylenna M, Nytrøen K (2015)
What matters to patients? A systematic review of preferences for medication-associated outcomes in mental disorders
BMJ Open, 5 (4), e007848
DOI 10.1136/bmjopen-2015-007848, PubMed 25854979

Nytrøen K, Yardley M, Rolid K, Bjørkelund E, Karason K, Wigh JP, Dall CH, Arora S, Aakhus S, Lunde K, Solberg OG, Gustafsson F, Prescott EI, Gullestad L (2015)
Design and rationale of the HITTS randomized controlled trial: Effect of High-intensity Interval Training in de novo Heart Transplant Recipients in Scandinavia
Am Heart J, 172, 96-105
DOI 10.1016/j.ahj.2015.10.011, PubMed 26856221

Yardley M, Havik OE, Grov I, Relbo A, Gullestad L, Nytrøen K (2015)
Peak oxygen uptake and self-reported physical health are strong predictors of long-term survival after heart transplantation
Clin Transplant, 30 (2), 161-9
DOI 10.1111/ctr.12672, PubMed 26589579

Publications 2013

Nytrøen K, Gullestad L (2013)
[Exercise after heart transplantation--old principles needs reevaluation]
Tidsskr Nor Laegeforen, 133 (19), 2030-1
DOI 10.4045/tidsskr.13.0903, PubMed 24129530

Nytrøen K, Gullestad L (2013)
Effect of exercise in heart transplant recipients
Am J Transplant, 13 (2), 527
DOI 10.1111/ajt.12046, PubMed 23356900

Nytrøen K, Gullestad L (2013)
Exercise after heart transplantation: An overview
World J Transplant, 3 (4), 78-90
DOI 10.5500/wjt.v3.i4.78, PubMed 24392312

Nytrøen K, Rustad LA, Erikstad I, Aukrust P, Ueland T, Lekva T, Gude E, Wilhelmsen N, Hervold A, Aakhus S, Gullestad L, Arora S (2013)
Effect of high-intensity interval training on progression of cardiac allograft vasculopathy
J Heart Lung Transplant, 32 (11), 1073-80
DOI 10.1016/j.healun.2013.06.023, PubMed 23906899

Rustad LA, Nytrøen K, Andreassen A, Geiran O, Endresen K, Gullestad L, Aakhus S, Amundsen BH (2013)
Heart transplant systolic and diastolic function is impaired by prolonged pretransplant graft ischaemic time and high donor age: an echocardiographic study
Eur J Cardiothorac Surg, 44 (2), e97-104
DOI 10.1093/ejcts/ezt233, PubMed 23657552

Publications 2012

Nytrøen K, Rustad LA, Aukrust P, Ueland T, Hallén J, Holm I, Rolid K, Lekva T, Fiane AE, Amlie JP, Aakhus S, Gullestad L (2012)
High-intensity interval training improves peak oxygen uptake and muscular exercise capacity in heart transplant recipients
Am J Transplant, 12 (11), 3134-42
DOI 10.1111/j.1600-6143.2012.04221.x, PubMed 22900793

Nytrøen K, Rustad LA, Gude E, Hallén J, Fiane AE, Rolid K, Holm I, Aakhus S, Gullestad L (2012)
Muscular exercise capacity and body fat predict VO(2peak) in heart transplant recipients
Eur J Prev Cardiol, 21 (1), 21-9
DOI 10.1177/2047487312450540, PubMed 22659939

Rustad LA, Nytrøen K, Amundsen BH, Gullestad L, Aakhus S (2012)
One year of high-intensity interval training improves exercise capacity, but not left ventricular function in stable heart transplant recipients: a randomised controlled trial
Eur J Prev Cardiol, 21 (2), 181-91
DOI 10.1177/2047487312469477, PubMed 23185084

Publications 2011

Nytrøen K, Myers J, Chan KN, Geiran OR, Gullestad L (2011)
Chronotropic responses to exercise in heart transplant recipients: 1-yr follow-up
Am J Phys Med Rehabil, 90 (7), 579-88
DOI 10.1097/PHM.0b013e31821f711d, PubMed 21765276

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