Effects of different intensity endurance training on atrial fibrillation in Rats

Abstract

Background Exercise has a positive effect on various cardiovascular diseases. However, it is not uncommon to experience arrhythmia events during or after exercising. Objective To determine how to maximize the benefits of exercise while ensuring safety. Methods we conducted a study involving 40 adult Sprague-Dawley rats. These rats underwent exercise of different intensities for 8 weeks. We recorded electrophysiological stimulation to track the occurrence and duration of atrial fibrillation, along with other electrophysiological data. Additionally, we analyzed and observed the histology of cardiomyocytes. Results The results revealed a relationship between exercise intensity and the incidence of atrial fibrillation and myocardial lipid deposition. As exercise intensity increased, there were an increase in myocardial fibrosis, mitochondrial activity, and autophagy and a decrease in reactive oxygen species. The expression of NCX1 and Kv1.5 proteins in rat atrial cardiomyocytes exhibited varying degrees of change. The increase in myocardial lipid level after exercise is thought to have a significant effect on myocardial fibrosis, which may be related to the upregulation of peroxisome proliferator-activated receptor-gamma coactivator 1 alpha expression. Conclusion Sustained and moderate-intensity exercise is considered more suitable for improving myocardial metabolic energy supply and treating atrial arrhythmias.