Interval and continuous aerobic exercise training similarly increase cardiac function and autonomic modulation in infarcted mice

Abstract

The present study aimed to compare the effects of moderate-intensity continuous and high-intensity interval exercise training (ET) on exercise tolerance, cardiac morphometry and function, hemodynamic, and cardiac autonomic modulation in myocardial infarcted mice. Wild-type mice (WT) were divided into four groups: sedentary WT (S); WT myocardium infarction sedentary (IS); WT myocardium infarction underwent to moderate-intensity continuous ET (MICT), and WT myocardium infarction underwent to high-intensity interval ET (MIIT). After 60 days of descending coronary artery ligation, moderate-intensity continuous ET consisted of running at 60% of maximum, while the high-intensity interval training consisted of eight sprints of 4 min at 80% of maximum and a 4-min recovery at 40% of maximum. Both exercises were performed 1 hr a day, 5 days a week, during 8 weeks. Results demonstrated that IS showed elevated exercise tolerance, as well as decreased hemodynamic and heart function, and autonomic control. On the other hand, both programs of ET were equally effective to increase all parameters, without further differences between the groups. In conclusion, the results of the present study showed that myocardial infarction leads to damage in both investigated strains and the two types of physical exercise attenuated the major impairments provoked by myocardial infarction in exercise tolerance, cardiac structure, cardiac function, hemodynamic and cardiac autonomic modulation.

Effects of Exercise Intensity on Cardiometabolic Parameters of Ovariectomized Obese Mice

“…The analysis in the PI and SAP frequency domain was performed using the Fast Fourier Transform to obtain the power spectrum of the low frequency (LF, 0.40-1.50 Hz) and high frequency bands (HF, 1.50-5.0 Hz -only for the PI). The bands were presented in nor malized units [28,32,33]. In addition, the BF/AF ratio (sympatho vagal balance) was calculated.…”

“…The animals were anesthetized (0.5 % -2 % isoflurane, 98 % O 2, 1.5 L/ min) [28], and a Tygon polyethylene cannula was implanted in the carotid artery for direct AP measurement, and jugular vein for drug administration Tramadol 60 mg/kg (i.p.) was administered every 12 hours for analgesic effects [12,13,28].…”

“…The animals were anesthetized (0.5 % -2 % isoflurane, 98 % O 2, 1.5 L/ min) [28], and a Tygon polyethylene cannula was implanted in the carotid artery for direct AP measurement, and jugular vein for drug administration Tramadol 60 mg/kg (i.p.) was administered every 12 hours for analgesic effects [12,13,28]. Twenty-four hours after the surgery, the arterial cannula was connected to a transducer (Kent Instruments) connected to a preamplifier (Stemtech).…”

Animal Models of Exercise From Rodents to Pythons

“…97 Given the beneficial physiological cardiac adaptions of HIIT training, several investigations have studied the potential benefits of HIIT in animal models of cardiac disease states. When performed after MI in rodent models, HIIT has been shown to improve exercise capacity, [141][142][143][144] attenuate ventricular and cellular hypertrophy, 39 restore FS, 39,[144][145][146][147] ejection fraction, 95,143,[147][148][149] and diastolic dysfunction, 94,141,147 as well as normalize cardiomyocyte Ca 2+ handling and sensitivity, 39,142,144,146 alleviate mitochondrial dysfunction, 145 preserve endothelial function, 95 increase angiogenesis, 94 and reduce collagen accumulation. 94 In models of diet-induced obesity, low exercise capacity, and diabetic cardiomyopathy, HIIT has conferred therapeutic improvements in VO 2max 53,150,151 systolic and diastolic function, 150,151 cardiac mechanoenergetics, 150,152 and cardiac fibrosis, 150,151 as well as alterations of cholesterol, 53 insulin resistance, 151 and substrate utilization.…”

Comparison of the Effect of Continuous and Interval Aerobic Training on Electrocardiogram of Active Young Girls

“…In addition to exercise volume (intensity and duration) and type of exercise, other factors such as age, gender, and race also play a role in the development of certain ECG patterns [2]. Cal Abad (2017) showed that continuous and interval training aerobic exercise similarly increases cardiac function and autonomic modulation in mice with myocardial infarction [11], but they did not mention how exercise do affect the ECG of the subjects. Most previous studies that have examined the effect of exercise on ECG indicators are retrospective, causal-comparative (post-event) type [4][5][6][7][8]10], and few experimental and prospective studies have been conducted in this area [9].…”