Live high-train low for 24 days increases hemoglobin mass and red cell volume in elite endurance athletes

The effect of live high-train low on hemoglobin mass (Hb(mass)) and red cell volume (RCV) in elite endurance athletes is still controversial. We expected that Hbmass and RCV would increase, when using a presumably adequate hypoxic dose. An altitude group (AG) of 10 Swiss national team orienteers (5 men and 5 women) lived at 2,500 m ( 18 h per day) and trained at 1,800 and 1,000 m above sea level for 24 days. Before and after altitude, Hb(mass), RCV (carbon monoxide rebreathing method), blood, iron, and performance parameters were determined. Seven Swiss national team cross-country skiers (3 men and 4 women) served as sea level (500 - 1,600 m) control group (CG) for the changes in Hbmass and RCV. The AG increased Hbmass (805 +/- 209 vs. 848 +/- 225 g; P < 0.01) and RCV (2,353 +/- 611 vs. 2,470 +/- 653 ml; P < 0.01), whereas there was no change for the CG (Hb(mass): 849 +/- 197 vs. 858 +/- 205 g; RCV: 2,373 +/- 536 vs. 2,387 +/- 551 ml). Serum erythropoietin (P < 0.001), reticulocytes (P < 0.001), transferrin (P < 0.001), soluble transferrin receptor (P < 0.05), and hematocrit (P < 0.01) increased, whereas ferritin (P < 0.05) decreased in the AG. These changes were associated with an increased maximal oxygen uptake (3,515 +/- 837 vs. 3,660 +/- 770 ml/min; P < 0.05) and improved 5,000-m running times (1,098 +/- 104 vs. 1,080 +/- 98 s; P < 0.01) from pre- to postaltitude. Living at 2,500 m and training at lower altitudes for 24 days increases Hbmass and RCV. These changes may contribute to enhance performance of elite endurance athletes.