A1 Refereed original research article in a scientific journal
Left ventricular vascular and metabolic adaptations to high-intensity interval and moderate intensity continuous training: a randomized trial in healthy middle-aged men
Authors: Jari-Joonas Eskelinen, Ilkka Heinonen, Eliisa Löyttyniemi, Juuso Hakala, Marja A. Heiskanen, Kumail K. Motiani, Kirsi Virtanen, Jussi P. Pärkkä, Juhani Knuuti, Jarna C. Hannukainen, Kari K. Kalliokoski
Publication year: 2016
Journal: Journal of Physiology
Journal name in source: The Journal of physiology
Journal acronym: J Physiol
Volume: 594
Issue: 23
First page : 7127
Last page: 7140
Number of pages: 14
ISSN: 1469-7793
DOI: https://doi.org/10.1113/JP273089
Abstract
High-intensity interval training (HIIT) is time-efficient way to get the health benefits of exercise, but the cardiac effects of this training mode are incompletely known. We compared the effects of short-term HIIT and moderate intensity continuous training (MICT) interventions on myocardial perfusion and metabolism and cardiac function in healthy, sedentary, middle-aged men. Twenty-eight healthy, middle-aged men were randomized to either HIIT or MICT groups (n = 14 in both) and underwent six cycle ergometer training sessions within two weeks (HIIT session: 4-6 × 30 s all-out cycling / 4 min recovery, MICT session 40-60 min at 60 % VO2 peak). Cardiac magnetic resonance imaging (CMRI) was performed to measure cardiac structure and function and positron emission tomography to measure myocardial perfusion at baseline and during adenosine stimulation, insulin-stimulated glucose uptake (MGU) and fasting free fatty acid uptake (MFFAU). End-diastolic and end-systolic volumes increased and ejection fraction slightly decreased with both training modes, but no other changes in CMRI were observed. MFFAU and basal myocardial perfusion remained unchanged. MGU decreased by training (HIIT from 46.5 to 35.9, MICT from 47.4 to 44.4 mmol · 100 g(-1) · min(-1) , P = 0.007 for time, P = 0.11 for group*time). Adenosine-stimulated myocardial perfusion responded differently to the training modes (change in mean HIIT -19 %, MICT +9 %, P = 0.03 for group*time interaction). HIIT and MICT induce similar metabolic and functional changes in the heart, but myocardial vascular hyperaemic reactivity is impaired after HIIT. This should be taken into account when prescribing very intense HIIT for previously untrained subjects. This article is protected by copyright. All rights reserved.
High-intensity interval training (HIIT) is time-efficient way to get the health benefits of exercise, but the cardiac effects of this training mode are incompletely known. We compared the effects of short-term HIIT and moderate intensity continuous training (MICT) interventions on myocardial perfusion and metabolism and cardiac function in healthy, sedentary, middle-aged men. Twenty-eight healthy, middle-aged men were randomized to either HIIT or MICT groups (n = 14 in both) and underwent six cycle ergometer training sessions within two weeks (HIIT session: 4-6 × 30 s all-out cycling / 4 min recovery, MICT session 40-60 min at 60 % VO2 peak). Cardiac magnetic resonance imaging (CMRI) was performed to measure cardiac structure and function and positron emission tomography to measure myocardial perfusion at baseline and during adenosine stimulation, insulin-stimulated glucose uptake (MGU) and fasting free fatty acid uptake (MFFAU). End-diastolic and end-systolic volumes increased and ejection fraction slightly decreased with both training modes, but no other changes in CMRI were observed. MFFAU and basal myocardial perfusion remained unchanged. MGU decreased by training (HIIT from 46.5 to 35.9, MICT from 47.4 to 44.4 mmol · 100 g(-1) · min(-1) , P = 0.007 for time, P = 0.11 for group*time). Adenosine-stimulated myocardial perfusion responded differently to the training modes (change in mean HIIT -19 %, MICT +9 %, P = 0.03 for group*time interaction). HIIT and MICT induce similar metabolic and functional changes in the heart, but myocardial vascular hyperaemic reactivity is impaired after HIIT. This should be taken into account when prescribing very intense HIIT for previously untrained subjects. This article is protected by copyright. All rights reserved.
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