Morphological changes of myocardium and over-recovery law in model rats undergoing different intensities of periodic aerobic training

Zhang Jing; Zhang Li-na; Yang Ren-jun; Hu Yao

doi:10.3969/j.issn.2095-4344.2016.49.010

Abstract：BACKGROUND:“Over-recovery theory”is the basic theory of sports training, but study about the visceral over-recovery is few, let alone about heart after aerobic exercise. <br> OBJECTIVE:To observe the morphological changes of myocardial tissue in rats after different cycles of aerobic exercise, and the recovery pattern of heart function within 72 hours. <br> METHODS:132 Sprague-Dawley rats were randomly divided into groups of control (n=6), single-cycle (low-intensity exercise, n=42), double-cycle (moderate-intensity exercise, n=42), and triple-circle (high-intensity exercise, n=42). Rats in the latter three groups underwent 1-week adaptive swimming in accordance with the way of increasing load (from 3%to 6%), fol owed by aerobic exercise of swimming according to their corresponding training cycle. Subsequently, samples were col ected to detect the levels of creatine kinase, superoxide dismutase, succinic dehydrogenase and glutamic-oxaloacetic transaminase in myocardial tissue;left cardiac apex tissues after embedded section were observed by hematoxylin-eosin staining. <br> RESULTS AND CONCLUSION:(1) Compared with the control group, the morphological changes of myocardial tissue immediately after exercise became more obvious with the increasing intensity. (2) Compared with the control group, significantly increased levels of superoxide dismutase, succinic dehydrogenase and glutamic-oxaloacetic transaminase conld be found in the single-cycle group (P<0.05), and showed over-recovery at 12-36 hours after exercise;al indicators were significantly increased in the double-cycle group showing over-recovery at 24-48 hours (P<0.05);while in the triple-circle group, succinic dehydrogenase exhibited over-recovery only (P<0.05), and each indicator level was low probably indicating over fatigue. (3) These findings suggest that compared with the triple-cycle high-intensity training, single-cycle and double-cycle training wil be better, and it is advisable to undergo double-cycle aerobic exercise in practice.