INCREASED LEFT-VENTRICULAR MUSCLE MASS AFTER LONG-TERM ALTITUDE TRAINING IN ATHLETES

The effects of long-term altitude training on altitude and sea-level p hysiological characteristics in elite endurance athletes were investig ated. Seven Swedish elite cross-country skiers (five men, two women; m ean age 27 years) spent 1 month training at 1900 m above sea level in Italy. Rollerski treadmill tests were performed before and 5 and 11 da ys after the altitude sojourn, three tests were also performed at alti tude. Before and 1, 11 and 35 days after the altitude camp, echocardio graphic and blood volume measurements were performed. The heart rates at both maximal (P < 0.05) and submaximal (P < 0.01) work loads were d ecreased by 5-9 beats min(-1) at altitude. The haemoglobin concentrati on and haematocrit increased quickly at altitude with a corresponding decrease on return to sea level. The blood volume (7%) and total haemo globin (3%) tended to be higher day 11 post-altitude (MS). There were no significant changes in diastolic internal diameter or wall thicknes s of the left ventricle, but the calculated cardiac left ventricular m uscle mass was increased post-altitude (9-10%, P < 0.01). The maximal oxygen uptake increased in six of the seven skiers after the altitude training (day 11, mean 3%, NS). In conclusion, training at moderate al titude may cause a reduction in heart rates during exercise. Moreover, after long-term training at altitude, there may be an increase in the cardiac left ventricular muscle mass.