Endothelial dysfunction is one of the aetiological factors in ischaemic heart disease (IHD). Aerobic exercise is effective in improving endothelial function, as measured by flow-mediated dilation (FMD), in patients with IHD. Within the aerobic exercise methods, there is evidence showing that high-intensity interval training (HIIT) increases FMD to a greater extent than moderate-intensity training (MIT) in these patients. Notably, in a recent review, our research group found that only studies performing long bouts of HIIT (long HIIT: higher than 1 min) found a greater effect on FMD, while no differences were found in those studies using short bouts of HIIT (short HIIT: ≤ 1 min) and MIT. However, no experimental studies comparing the effect of long HIIT, short HIIT, and MIT on endothelial function, as well as other predictors of mortality, such as cardiorespiratory fitness, brain-derived neurotrophic factor (BDNF) levels or parasympathetic branch activity, have been performed. Therefore, the main objective of this project will be to compare the effect of the three aerobic exercise methods on endothelial function, as measured by FMD, in patients with IHD. Complementarily, the effect of aerobic exercise, depending on the exercise method, on different mortality predictors will be compared. For this purpose, a multicentre randomised study will be carried out (2 hospitals in Elche and one in Alicante). Assessors will be blinded to the patients allocation. Participants will be aware about their allocation in the experimental groups due to the nature of the study. A total of 132 men and women with IHD (66 per sex), diagnosed between three and 12 months before the start of the intervention, aged between 45 and 75 years, and without limitations for the practice of exercise training, will be recruited. All patients will train 3 days a week for 12 weeks. Participants will be assessed before the intervention (i.e., pre), at 6 weeks of training (i.e., mid) and after the intervention (i.e., post). Physiological and psychological variables will be registered in the assessment periods. Training intensity will be individually prescribed based on the cardiopulmonary exercise test (CPET). Intensity exercise will be adapted after the first part of the intervention. Analysis of covariance will be used to compare the values of the three groups after the intervention for the continuous variables, including the pre-intervention value as a covariate, while a logistic regression model will be used for the categorical variables.
Men and women aged between 45 and 75 years.
Diagnosed with acute myocardial infarction, unstable or stable angina.
Treated with percutaneous coronary intervention, coronary artery bypass grafting, or conservative treatment.
Event or intervention within 3 to 12 months prior to participation in the study.
Use of walking assistive devices.
Treatment with chemotherapy for any type of cancer in the past 2 years.
Hospitalisation in an intensive care unit in the past 6 months for reasons other than the ischaemic event.
Acute myocardial infarction group IV Killip-Kimball.
Parallel
Aerobic exercise (MIT)
BehavioralPatients allocated to the MIT group will train on a cycle ergometer three days a week for 12 weeks (36 sessions). They will cycle continuously between the first and second ventilatory thresholds. The duration of each exercise session will be set according to the estimated energy expenditure of the long HIIT and short HIIT groups for each training block (energy expenditure-adjusted exercise sessions). All sessions will be supervised, and patients will be asked to avoid additional exercise. They will be allowed to perform extra physical activity (e.g., light walking) according to medical recommendations.
Aerobic exercise (Short HIIT)
BehavioralPatients allocated to the Short HIIT group will train on a cycle ergometer three days a week for 12 weeks (36 sessions). They will perform from two to four 4-repetition sets of 1-min above the second ventilatory threshold. Patients will perform 1- and 3-min active recovery periods below the first ventilatory threshold between repetitions and sets, respectively. The total time spent at high intensity will range from eight to 16 min. All sessions will be supervised, and patients will be asked to avoid additional exercise training. They will be allowed to perform extra physical activity (e.g., light walking) according to medical recommendations.
Aerobic exercise (Long HIIT)
BehavioralPatients allocated to the Long HIIT will train on a cycle ergometer three days a week for 12 weeks (36 sessions). They will perform from two to four 4-min high-intensity exercise bouts above the second ventilatory threshold separated by 4-min active recovery periods below the first ventilatory threshold. The total time spent at high intensity will range from eight to 16 min. All sessions will be supervised, and patients will be asked to avoid additional exercise training. They will be allowed to perform extra physical activity (e.g., light walking) according to medical recommendations.
Change from baseline in endothelial function at 7 weeks
Endothelial function (i.e., endothelial-dependent dilation) will be assessed by brachial FMD.
Change from baseline in endothelial function at 14 weeks
Endothelial function (i.e., endothelial-dependent dilation) will be assessed by brachial FMD.
Change from baseline in endothelial-independent dilation at 7 weeks
Brachial NMD will be used to measure endothelial-independent dilation.
Change from baseline in endothelial-independent dilation at 14 weeks
Brachial NMD will be used to measure endothelial-independent dilation.
Change from baseline in pulmonary function at 7 and 14 weeks
Pulmonary function will be measured by spirometry
Change from baseline in resting cardiopulmonary parameters at 7 and 14 weeks
Patients will be asked to rest for 5 min before stating the CPET.
Change from baseline in cardiopulmonary parameters at first and second ventilatory thresholds at 7 and 14 weeks
First and second ventilatory threshold during the CPET will be analysed blindly using the ventilatory equivalents method.
Change from baseline in cardiopulmonary variables measured during the recovery at 7 and 14 weeks.
Cardiopulmonary variables will be measured during the 3-min recovery period of the CPET.
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Instituto de Investigación Sanitaria y Biomédica de Alicante
Lead sponsor
Universidad Miguel Hernandez de Elche
Collaborator
