IngentaConnect CARDIOVASCULAR ADAPTATIONS IN RATS SUBMITTED TO A RESISTANCE-TRAI...

Authors: Barauna, Valerio G¹; Junior, Miguel Luis B²; Costa Rosa, Luis Fernando BP²; Casarini, Dulce E³; Krieger, José Eduardo⁴; Oliveira, Edilamar M

Source: Clinical and Experimental Pharmacology and Physiology, Volume 32, Number 4, April 2005 , pp. 249-254(6)

Publisher: Blackwell Publishing

Abstract:

SUMMARY

1. The present study sought to evaluate cardiovascular adaptations, such as blood pressure (BP), heart rate (HR) and cardiac hypertrophy, to resistance training (RT) in a rat model.

2. The training protocol consisted of four sets of 10–12 repetitions of the squat exercise performed at 65–75% of one repetition maximum (1RM) over 4 weeks. Animals were randomly divided into three groups: control (n = 8, CO), electrically stimulated (n = 8, ES) and trained (n = 8, TR; also electrically stimulated). Blood pressure and HR were measured by a direct method in conscious rats after the training period.

3. All groups began with similar 1RM and 1RM/bodyweight (BW) ratio, however, at the end of the protocol only the TR group was different from the beginning (56% and 50%, respectively; both P < 0.01). The CO and ES groups had similar values for cardiac chambers weight/BW ratio, HR and diastolic, systolic and mean BP. Left ventricular hypertrophy (LVH) determined by the left ventricle (LV) weight/BW ratio was increased in the TR group (12%) when compared to CO (P < 0.01) or ES groups (P < 0.01). No changes were found in the weights of the atrium or right ventricle. Diastolic (14%) and mean BP (13%) were lower in the TR group (P < 0.05), whereas systolic BP and HR remained unchanged.

4. Collectively these results demonstrate that the rat RT model used is associated with significant development of cardiac hypertrophy and lowering of resting BP. These cardiovascular adaptations seem to a result of the training exercise and not influenced by stress since circulating catecholamine levels and adrenal gland weights remained unchanged in all groups.

Keywords: cardiovascular system; myocardial hypertrophy; resistance training; weight lifting

Document Type: Research article

DOI: 10.1111/j.1440-1681.2005.04180.x

Affiliations: 1: Laboratory of Biochemistry, School of Physical Education and Sport, University of São Paulo, São Paulo, 2: Laboratory of Metabolism, Institute of Biomedical Science, University of São Paulo, São Paulo, and 3: Nephrology Division, Kidney and Hypertension Hospital, UNIFESP, São Paulo, Brazil 4: Laboratory of Genetics and Molecular Cardiology and Unit of Applied Physiology, Heart Institute (InCor), University of São Paulo School of Medicine, São Paulo,

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CARDIOVASCULAR ADAPTATIONS IN RATS SUBMITTED TO A RESISTANCE-TRAINING MODEL