Cardiac fatigue following high altitude competitive running: No evidence for cumulative effect in the medium long term

The aim of this study was to assess the effects of prolonged, repetitive, competitive high altitude running on left ventricular performance. We studied 11 world-class athletes (8 males, 3 females, mean age 30 ± 3 years) in 2 consecutive years (1994-1995) before and after two high altitude races performed in Italy. On both occasions we recorded the 12-lead ECG as well as mono, two-dimensional and Doppler echocardiograms, 24 hours before, within 30 min and 24 hours after the end of the race. Measurements included heart rate, blood pressure, ejection fraction, early (E) and late (A) transmitral inflow velocities, their ratio (E/A) and percent atrial contribution (AC). Similar studies were obtained in 11 age and sex matched control subjects at baseline and following a maximal exercise testing. Blood pressure in athletes was not modified after both races, while heart rate immediately after the end of the race was significantly increased (p