Cardiovascular adaptations to intense swim training in sedentary middle-aged men and women

W. H. Martin, J. Montgomery, P. G. Snell, J. R. Corbett, J. J. Sokolov, J. C. Buckey, D. A. Maloney, C. G. Blomqvist

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Abstract

Central and peripheral cardiovascular adaptations to 12 weeks of intense swim training were characterized in 12 previously sedentary middle-aged men and women. Peak oxygen uptake (V̇O2) during upright bicycle exercise improved from 29.2 ± 5.6 to 34.7 ± 6.7 ml/kg/min (mean ± SD, p < .01) because of similar increases in peak cardiac output (CO) and calculated arteriovenous oxygen difference (both p = .02). Peak supine V̇O2 was 10% higher after training (p < .005) solely because of enhanced CO (p = .005). Peak heart rate decreased in both postures; therefore stroke volume at peak exercise was greater by 10% and 18% in the upright and supine postures, respectively (p = .05 and p = .005). There was an identical 18% rise (p = .01) in peak supine left ventricular end-diastolic volume index by radionuclide ventriculography but no change in left ventricular ejection fraction or end-systolic volume index (ESVI). Peak systolic blood pressure (SBP) was unchanged in the upright posture but was 8% higher (p = .002) during recumbency despite a similar total peripheral resistance and SBP/ESVI ratio. Maximal calf conductance (G(max)), assessed separately by venous occlusion plethysmography after local ischemic exercise to fatigue, was augmented 20% (p < .02) by training, resulting in an 18% greater hyperemic blood flow (p = .05). Peak V̇O2, CO, and G(max) were unchanged in five nonexercising control subjects. We conclude that in middle-aged humans, intense swim training for 12 weeks produces adaptations that include a greater capacity for vasodilatation in skeletal muscle and an enhanced cardiac pump capacity.

Original languageEnglish (US)
Pages (from-to)323-330
Number of pages8
JournalCirculation
Volume75
Issue number2
Publication statusPublished - 1987

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ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Martin, W. H., Montgomery, J., Snell, P. G., Corbett, J. R., Sokolov, J. J., Buckey, J. C., ... Blomqvist, C. G. (1987). Cardiovascular adaptations to intense swim training in sedentary middle-aged men and women. Circulation, 75(2), 323-330.