Journal of Mazandaran University of Medical Sciences (Nov 2023)
The Comparison between the Effect of Four Weeks High Fat Diet, Volume Reduction Training and Detraining Following of Six Weeks Exercise Training on Parameters of Exercise-induced Bradycardia in Female Rats
Abstract
Background and purpose: Exercise training-induced sinus bradycardia is a common cardiac adaptation and change in athlete’s related to a reduction in intrinsic heart rate. This study aimed to investigate the effect of four weeks of high fat diet, four weeks of exercise training volume reduction and four weeks of detraining following six weeks of high-volume exercise training on the level of Hyperpolarization-activated, cyclic nucleotide-gated (HCN4). Materials and methods: Thirty Sprague Dawley rats were divided into six groups randomly. Group 1 was the control group with standard diet. Group 2 was trained for ten weeks with high-volume exercise training and standard diet. Group 3 was trained for six weeks; after that, rats were trained with a volume reduction training protocol with standard diet. Group 4 was trained for six weeks; after that, rats were trained with a volume reduction training protocol with high fat diet. Group 5 was trained for six weeks and detrained for four weeks with high fat diet. Group 6 was trained for six weeks and detrained for four weeks with standard diet. After ten weeks, the level of HCN4 protein was assessed by Western Blotting for all groups. Results: Our results have revealed that all experimental groups showed a reduction in HCN4 levels compared to the control group—the lowest HCN4 level for groups 2, 6, 3, 4, 5 and 1, respectively (P≤0.05). Besides, the result of electrocardiograph has demonstrated that the heart rate and RR interval in all experimental groups showed a reduction and elevation compared to the control group, respectively (P≤0.05). Conclusion: Volume reduction training protocol in could restore sinus bradycardia effects rather than detraining after high-volume exercise training, but the effect of high fat diet should be investigated more.
