The Athlete’s Heart – Gender Aspects K. Steding1, H. Engblom1, M. Carlsson1, H. Mosén1, T. Buhre2, B. Wohlfart1, H. Arheden1 1Dept. Clinical Physiology, Lund University, 2Dept. Sport Sciences, Malmö University Introduction: Training induced morphological changes to the heart in male subjects has previously been well described. Only a few studies include females. Objective: The aim of this study was to investigate if the morphological response to training differs between male and female athletes. Methods: Eighteen triathletes (6 female) and 59 controls (19 female) underwent cardiac magnetic resonance imaging (CMR). Total heart volume (THV), left ventricular mass (LVM) and end diastolic volume (EDV) was calculated using planimetry derived from steady state free precession cine images. Mann-Whitney non-parametric t-test was used to compare THV/body surface area (BSA), LVM/THV and EDV/THV in the four groups. Results: THV/BSA was significantly higher in athletes, both for males and females (p<0.0001, p<0.001 respectively). Male controls had a significantly higher THV/BSA when compared to female controls (p=0.004) and also LVM/THV (p=0.001). However, there were no significant differences between male and female athletes for any of the variables studied. Conclusion: Long term endurance training increases THV in the same order of magnitude in both male and female athletes. The differences seen between male and female control subjects are not found in male and female athletes.