The aim of the present investigation was to examine how 8 weeks of intense endurance training influenced right and left ventricular volumes and mass in obese untrained subjects. Ten overweight subjects (19-47 years; body mass index of 34+/-5 kg/m(2)) underwent intensive endurance training (rowing) three times 30 min/week for 8 weeks at a relative intensity of 72+/-8% of their maximal heart rate response (mean+/-SD). Before and after 8 weeks of endurance training, the left and the right end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), stroke volume (SV) and ventricular mass (VM) were measured by Magnetic resonance imaging (MRI). Submaximal heart rate decreased from 126+/-5 to 113+/-3 b.p.m. (10%; P