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Exercise effects on cardiac size and left ventricular diastolic function: relationships to changes in fitness, fatness, blood pressure and insulin resistance
  1. K J Stewart,
  2. P Ouyang,
  3. A C Bacher,
  4. S Lima,
  5. E P Shapiro
  1. The Division of Cardiology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland USA
  1. Correspondence to:
    Professor Kerry J Stewart
    Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue, Baltimore, MD 21224, USA; kstewart{at}jhmi.edu

Abstract

Objectives: To determine exercise training effects on cardiac size and left ventricular (LV) diastolic function and relationships of exercise induced changes in physiological and body composition parameters with cardiac parameters.

Design: Prospective, randomised controlled trial.

Subjects: Men and women (63.6 (5.7) years, body mass index 29.5 (4.4) kg/m2) with untreated hypertension (systolic blood pressure (BP) 130–159 or diastolic BP 85–99 mm Hg).

Main outcome measures: Cardiac size and LV diastolic function, peak oxygen uptake (Vo2), muscle strength, general and abdominal fatness, and insulin resistance.

Interventions: 6 months of exercise training versus usual care.

Results: When analysed by group at six months, cardiac size and LV diastolic function did not differ between exercisers (n  =  51) and controls (n  =  53), whereas exercisers had significantly higher peak Vo2 (28 v 24 ml/kg/min) and strength (383 v 329 kg), and lower fatness (34% v 37%), diastolic BP (73 v 75 mm Hg) and insulin resistance (quantitative insulin sensitivity check index 0.35 v 0.34) versus controls (all p ⩽ 0.05). By regression analysis, among six month changes, increased peak Vo2 and reduced abdominal fat were associated with increased cardiac size. Increased peak Vo2 and reduced abdominal fat, BP and insulin resistance were associated with improved LV diastolic function. r Values ranged from 0.20 to 0.32 (p ⩽ 0.05).

Conclusions: When examined by group assignment, exercise had no effect on cardiac size or LV diastolic function. When individual variations in six month changes were examined, participants attaining the greatest increases in fitness and reductions in abdominal fatness, insulin resistance and BP showed a modest trend towards physiological hypertrophy characterised by increased cardiac size and improved LV diastolic function. These results suggest that decreased abdominal fatness may have a role in improving cardiovascular health.

  • A, peak late diastolic filling wave velocity
  • Am, peak mitral annular late diastolic velocity during atrial contraction
  • BP, blood pressure
  • DBP, diastolic blood pressure
  • E, peak early diastolic filling wave velocity
  • Em, peak mitral annular early diastolic velocity
  • LV, left ventricular
  • MRI, magnetic resonance imaging
  • QUICKI, quantitative insulin sensitivity check index
  • SBP, systolic blood pressure
  • Vo2, oxygen uptake
  • exercise
  • blood pressure
  • obesity
  • diastole
  • cardiac structure

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Footnotes

  • Published Online First 24 November 2005

  • This study was supported by a grant from the Heart, Lung, and Blood Institute, National Institutes of Health, R01HL59164 (Dr Stewart), and by the Johns Hopkins Bayview General Clinical Research Center (GCRC), M01-RR-02719, from the National Center for Research Resources, National Institutes of Health. The funding organisations were not involved in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.

  • Competing interests: none declared

  • Ethics approval: The Johns Hopkins Institutional Review Board, Baltimore, Maryland, approved the study. Informed written consent was obtained from each participant.

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