\( \dot V{O_2} \) on-Transient Kinetics with a Centrally Acting Calcium Channel Blocker

  • R. J. Petrella
  • D. A. Cunningham
  • D. H. Paterson
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 393)

Abstract

We (1) have recently shown that maximal aerobic capacity \((\dot V{O_{2\max }})\) is increased significantly in normal elderly subjects coincident with improved left ventricular diastolic function following ingestion of the centrally acting Ca2+ channel blocker, verapamil. In addition, we have shown that exercise training has resulted in increased \(\dot V{O_{2\max }}\) and faster gas exchange kinetics among the elderly (2). Hughson and Smyth (3) reported a slower increase of \(\dot V{O_2}\) to steady state with submaximal exercise and Tesch and Kaiser (4) reported a lower \(\dot V{O_{2\max }}\) under the influence of β-adrenergic blockade in normal young subjects. The slowed responses in elderly subjects (2) and younger subjects (3) during β-adrenergic blockade may reflect impaired central or peripheral components of the \(\dot V{O_2}\) response (5,6). Whipp et al. (7) have described the kinetics of the gas transport system by a first order model and termed the initial 20s of the \(\dot V{O_2}\) response “cardiodynamic”. This period reflects the central or cardiac component of the \(\dot V{O_2}\) on-transient (Phase 1). The effects of a centrally acting Ca2+ channel blocker which increased \(\dot V{O_{2\max }}\) and improved left ventricular function in the elderly (1), may also be reflected in improved kinetics in the non-steady state response to an exercise perturbation. This may result from improvement in the central component of the \(\dot V{O_2}\) on-transient response. In order to examine this, we have analyzed the gas exchange responses in elderly men to a step increase in power output to a sub-anaerobic threshold level (40 W) before and 4 hours after ingestion of 240mg of verapamil SR.

Keywords

Verapamil Lawson 

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Copyright information

© Springer Science+Business Media New York 1995

Authors and Affiliations

  • R. J. Petrella
    • 1
  • D. A. Cunningham
    • 1
  • D. H. Paterson
    • 1
  1. 1.Faculties of Medicine and Kinesiology and The Centre for Activity and AgeingThe University of Western OntarioLondonCanada

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