Zheng Molin, Liu Chuanan, Lv Yuanyuan, Mi Jing, Qiu Dan, He Lingxiao, Zhao Li
Department of Exercise Physiology, Beijing Sport University, Beijing, China.
School of Competitive Sports, Beijing Sport University, Beijing, China.
Front Physiol. 2022 Jun 28;13:900661. doi: 10.3389/fphys.2022.900661. eCollection 2022.
Comparisons between high intensity interval training (HIIT) and continuous training (CT) regarding improvements of adolescents' cardiac function are scarce and the preferred intensity for cardiac improvement with restricted myocardial damage remains unknown. This study conducted a 4-weeks training in male adolescent rats under moderate (MI) or high intensity (HI) HIIT and CT programs, aiming to discover and compare exercise-induced myocardial adaptations towards these two training methods. 39 male adolescent Sprague-Dawley rats (aged 4 weeks) were randomly assigned to high intensity HIIT (HI-HIIT, = 8), moderate intensity HIIT (MI-HIIT, = 8), high intensity CT (HI-CT, = 8), moderate intensity CT (MI-CT, = 8) and sedentary control (SC, = 7) groups. Rats in training groups were trained for 4 weeks and echocardiography was performed at baseline and after the final training. Serum creatine kinase myocardial band (CK-MB), cardiac troponin T (cTn-T) and untargeted metabolomics analysis were measured from blood samples collected 24 h after the final training. HIIT groups had greater cardiac output improvement than CT groups while no significant difference was found between the HI-HIIT and the MI-HIIT groups. HI-CT group showed higher serum CK-MB and cTn-T levels compared to MI-HIIT, MI-CT and control groups. Untargeted metabolomics analysis identified eleven HI-HIIT-related metabolites, five MI-HIIT-related metabolites and two HICT-related metabolites. The majority of the identified metabolites were phospholipid-related. Phosphatidylglyceride 18 level was significantly different between the HI-CT and MI-CT groups, and was negatively associated with cTn-T in CT groups. HIIT and CT improve cardiac function of adolescent rats while the HIIT demonstrates better improvement and less myocardial damage. High and moderate training intensities in HIIT exert similar cardiac benefits. HI-CT induced myocardial damage might be associated with serum phospholipids.
关于高强度间歇训练（HIIT）和持续训练（CT）对青少年心脏功能改善的比较研究较少，且在限制心肌损伤的情况下，促进心脏功能改善的最佳强度仍不明确。本研究对雄性青春期大鼠进行了为期4周的中等强度（MI）或高强度（HI）的HIIT和CT训练，旨在发现并比较这两种训练方式对运动诱导的心肌适应性的影响。39只4周龄的雄性青春期斯普拉格-道利大鼠被随机分为高强度HIIT组（HI-HIIT，n = 8）、中等强度HIIT组（MI-HIIT，n = 8）、高强度CT组（HI-CT，n = 8）、中等强度CT组（MI-CT，n = 8）和久坐对照组（SC，n = 7）。训练组大鼠进行4周训练，并在基线和末次训练后进行超声心动图检查。在末次训练24小时后采集血样，检测血清肌酸激酶心肌型同工酶（CK-MB）、心肌肌钙蛋白T（cTn-T）并进行非靶向代谢组学分析。HIIT组的心输出量改善程度大于CT组，而HI-HIIT组和MI-HIIT组之间未发现显著差异。与MI-HIIT组、MI-CT组和对照组相比，HI-CT组的血清CK-MB和cTn-T水平更高。非靶向代谢组学分析确定了11种与HI-HIIT相关的代谢物、5种与MI-HIIT相关的代谢物和2种与HI-CT相关的代谢物。大多数鉴定出的代谢物与磷脂有关。HI-CT组和MI-CT组之间的磷脂酰甘油18水平存在显著差异，且在CT组中与cTn-T呈负相关。HIIT和CT均可改善青春期大鼠的心脏功能，而HIIT表现出更好的改善效果且心肌损伤更小。HIIT中的高、中训练强度对心脏的益处相似。HI-CT诱导的心肌损伤可能与血清磷脂有关。
