Research

Left ventricular systolic performance during prolonged strenuous exercise in female triathletes

Jonathan McGavock¹, Mark Haykowsky^2,3, Darren Warburton^1,4, Dylan Taylor³, Arthur Quinney¹ and Robert Welsh³

¹  Faculty of Physical Education, University of Alberta, Edmonton, AB. Canada

²  Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB. Canada

³  Division of Cardiology, Faculty of Medicine, University of Alberta, Edmonton, AB. Canada

⁴  Current address: Allan McGavin Sports Medicine Centre, Faculty of Physical Education, University of British Columbia, Vancouver, BC. Canada

Dynamic Medicine 2003, 2:2doi:10.1186/1476-5918-2-2

Published:	8 April 2003

Abstract

Background

The effect of prolonged strenuous exercise (PSE) on left ventricular (LV) systolic function has not been well studied in younger female triathletes. This study examined LV systolic function prior to, during and immediately following PSE (i.e., 40 km bicycle time trial followed by a 10 km run) in 13 younger (29 ± 6 years) female triathletes.

Methods

Two-dimensional echocardiographic images were obtained prior to, at 30-minute intervals during and immediately following PSE. Heart rate, systolic blood pressure, end-diastolic and end-systolic cavity areas were measured at each time point. Echocardiographic and hemodynamic measures were also combined to obtain LV end-systolic wall stress and myocardial contractility (i.e., systolic blood pressure – end-systolic cavity area relation).

Results

Subjects exercised at an intensity equivalent to 90 ± 3% of maximal heart rate. Heart rate, systolic blood pressure, systolic blood pressure – end-systolic cavity area relation and fractional area change increased while end-diastolic and end-systolic cavity areas decreased during exertion.

Conclusions

PSE is associated with enhanced LV systolic function secondary to an increase in myocardial contractility in younger female triathletes.