title: Left ventricular systolic performance during prolonged strenuous exercise in female triathletes.
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 PlusMinus; 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 PlusMinus; 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.
authors.affiliation: Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada. mark.haykowsky@ualberta.ca
authors.forename: Jonathan
authors.initials: J
authors.lastname: McGavock
authors.forename: Mark
authors.initials: M
authors.lastname: Haykowsky
authors.forename: Darren
authors.initials: D
authors.lastname: Warburton
authors.forename: Dylan
authors.initials: D
authors.lastname: Taylor
authors.forename: Arthur
authors.initials: A
authors.lastname: Quinney
authors.forename: Robert
authors.initials: R
authors.lastname: Welsh