Effects of strenuous exercise on the quantitative morphology of left ventricular myocardium in the rat

Anversa, Piero; Beghi, Cesare; Levicky, V.; McDonald, Susan L.; Kikkawa, Yutaka; Olivetti, G

doi:10.1016/s0022-2828(85)80027-4

Cited by 29 publications

(9 citation statements)

References 17 publications

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“…Physiologic LV hypertrophy due to an episodic volume load, such as that caused by physical activity, results from the addition of sarcomeres in series accounting for the lengthening of cardiac myocytes and increase in mass, a process distinct from the concentric hypertrophy that results from a pressure load (e.g., high blood pressure or weight-lifting) (18,19). Studies of the hearts of exercised animals compared with those of sedentary animals show hypertrophy of the RV out of proportion to the LV, with a 21 to 31% increase in RV mass and 7 to 12% increase in LV mass, as well as an increase in RV and septal myocyte length of up to 26% (20)(21)(22)(23). A recent study in rats with stable pulmonary hypertension suggested that physical activity helped to improve RV function and remodeling, but in those with progressive pulmonary hypertension physical activity accelerated RV failure (24).…”

Section: Discussionmentioning

confidence: 99%

Physical Activity and Right Ventricular Structure and Function

Aaron¹,

Tandri²,

Barr³

et al. 2011

Am J Respir Crit Care Med

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Section: Discussionmentioning

confidence: 99%

Physical Activity and Right Ventricular Structure and Function

Aaron¹,

Tandri²,

Barr³

et al. 2011

Am J Respir Crit Care Med

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“…Anversa et al (13) showed that a moderate treadmill exercise program increased capillary numerical density in the right but not the left ventricle. Following a more strenuous exercise program, capillary numerical density again did not change in the left ventricle (12), but actually decreased in the right ventricle (11,14). These findings raise concern that combined analysis of tissue from both ventricles might obscure individual differences in capillarization induced by exercise training in either the left or the right ventricle.…”

Section: Structural Adaptationsmentioning

confidence: 97%

Regulation of Coronary Blood Flow During Exercise

Duncker

Bache

2008

Physiological Reviews

783

684

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Exercise is the most important physiological stimulus for increased myocardial oxygen demand. The requirement of exercising muscle for increased blood flow necessitates an increase in cardiac output that results in increases in the three main determinants of myocardial oxygen demand: heart rate, myocardial contractility, and ventricular work. The approximately sixfold increase in oxygen demands of the left ventricle during heavy exercise is met principally by augmenting coronary blood flow (~5-fold), as hemoglobin concentration and oxygen extraction (which is already 70-80% at rest) increase only modestly in most species. In contrast, in the right ventricle, oxygen extraction is lower at rest and increases substantially during exercise, similar to skeletal muscle, suggesting fundamental differences in blood flow regulation between these two cardiac chambers. The increase in heart rate also increases the relative time spent in systole, thereby increasing the net extravascular compressive forces acting on the microvasculature within the wall of the left ventricle, in particular in its subendocardial layers. Hence, appropriate adjustment of coronary vascular resistance is critical for the cardiac response to exercise. Coronary resistance vessel tone results from the culmination of myriad vasodilator and vasoconstrictors influences, including neurohormones and endothelial and myocardial factors. Unraveling of the integrative mechanisms controlling coronary vasodilation in response to exercise has been difficult, in part due to the redundancies in coronary vasomotor control and differences between animal species. Exercise training is associated with adaptations in the coronary microvasculature including increased arteriolar densities and/or diameters, which provide a morphometric basis for the observed increase in peak coronary blood flow rates in exercise-trained animals. In larger animals trained by treadmill exercise, the formation of new capillaries maintains capillary density at a level commensurate with the degree of exercise-induced physiological myocardial hypertrophy. Nevertheless, training alters the distribution of coronary vascular resistance so that more capillaries are recruited, resulting in an increase in the permeability-surface area product without a change in capillary numerical density. Maintenance of alpha- and ss-adrenergic tone in the presence of lower circulating catecholamine levels appears to be due to increased receptor responsiveness to adrenergic stimulation. Exercise training also alters local control of coronary resistance vessels. Thus arterioles exhibit increased myogenic tone, likely due to a calcium-dependent protein kinase C signaling-mediated alteration in voltage-gated calcium channel activity in response to stretch. Conversely, training augments endothelium-dependent vasodilation throughout the coronary microcirculation. This enhanced responsiveness appears to result principally from an increased expression of nitric oxide (NO) synthase. Finally, physical conditioning decreases e...

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“…Thus it would be expected that exercise at higher intensities provides a greater stimulus for capillary growth than that of moderate exercise. Surprisingly, the chronic effects of intense or extraneous exercise on myocardial vasculature have been sparsely studied [14, 15] and yet no specific impact of exercise intensity can be derived from those, since the total exercise volume was not controlled. In other words, if an exercise training regime is employed leading to an increased total training volume, a resulting greater physiological adaptation could be attributed to the higher total amount of work and not to the specific impact of the intensity itself.…”

Section: Introductionmentioning

confidence: 99%

Interval and Continuous Exercise Training Produce Similar Increases in Skeletal Muscle and Left Ventricle Microvascular Density in Rats

Pereira

Moraes

Tibiriçá

et al. 2013

BioMed Research International

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Interval training (IT), consisting of alternated periods of high and low intensity exercise, has been proposed as a strategy to induce more marked biological adaptations than continuous exercise training (CT). The purpose of this study was to assess the effects of IT and CT with equivalent total energy expenditure on capillary skeletal and cardiac muscles in rats. Wistar rats ran on a treadmill for 30 min per day with no slope (0%), 4 times/week for 13 weeks. CT has constant load of 70% max; IT has cycles of 90% max for 1 min followed by 1 min at 50% max. CT and IT increased endurance and muscle oxidative capacity and attenuated body weight gain to a similar extent (P > 0.05). In addition, CT and IT similarly increased functional capillary density of skeletal muscle (CT: 30.6 ± 11.7%; IT: 28.7 ± 11.9%) and the capillary-to-fiber ratio in skeletal muscle (CT: 28.7 ± 14.4%; IT: 40.1 ± 17.2%) and in the left ventricle (CT: 57.3 ± 53.1%; IT: 54.3 ± 40.5%). In conclusion, at equivalent total work volumes, interval exercise training induced similar functional and structural alterations in the microcirculation of skeletal muscle and myocardium in healthy rats compared to continuous exercise training.

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Effects of strenuous exercise on the quantitative morphology of left ventricular myocardium in the rat

Cited by 29 publications

References 17 publications

Physical Activity and Right Ventricular Structure and Function

Physical Activity and Right Ventricular Structure and Function

Regulation of Coronary Blood Flow During Exercise

Interval and Continuous Exercise Training Produce Similar Increases in Skeletal Muscle and Left Ventricle Microvascular Density in Rats

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