Regression of cardiac hypertrophy: Morphometric and biochemical studies in rat heart after swimming training1

Moderate endurance training prevents doxorubicin-induced in vivo mitochondriopathy and reduces the development of cardiac apoptosis

“…Nevertheless, moderate and systematic exercise generally is an excellent tool to provide enhanced parallel resistance to the cardiac muscle (3,4). It is possible that mitochondrial structural and biochemical adaptations induced by training, such as increased volume density, heat shock protein (HSP) expression, and upregulation of antioxidant enzyme activity, could be related to traininginduced enhanced cardiac resistance (18,25,44). This phenomenon, usually referred to as cross-tolerance, has been demonstrated by several studies in which endurance training induced cardioprotection after acute stress stimuli (13,43).…”

Aerobic Fitness Is Associated With Cardiomyocyte Contractile Capacity and Endothelial Function in Exercise Training and Detraining

“…Accordingly, changes in cardiomyocyte size and function parallel those observed in V O 2 max when an exercise regimen is implemented and withdrawn. Whereas regular exercise is known to increase cardiomyocyte function and dimensions [3][4][5][6] as well as endothelium-dependent arterial relaxation, 6 -10 the response to detraining has yet to be defined. In humans, detraining decreases V O 2 max, but myocardial and arterial effects remain unclear.…”

“…[11][12][13] Reported regression of training-induced hypertrophy ranges from none 13 to 20% over a period of 3 weeks. 14 Experimental data suggest hypertrophy regression at varying time courses, 3,[15][16][17] with no account on cardiomyocyte or arterial function. Thus, the aim of the present study was to assess the cardiomyocyte contractile capacity and endothelium-dependent arterial relaxation changes in animals undergoing a controlled program of exercise training and detraining.…”

Effects of Different Intensity Endurance Training on the Capillary Network in Rat Skeletal Muscle

“…There have been reports that the capillary luminal diameter of the heart muscle is augmented by endurance training in rats [1,2]. Their findings suggest that the capil lary luminal diameter can be altered in an adaptive response to increased muscle activity.…”