EFFECT OF 40 DAYS SLEEPING IN NORMOBARIC HYPOXIA ON TOTAL HEMOGLOBIN MASS IN COMPETITIVE RUNNERS

Abstract

Living high and training low is a concept which allegedly provides the hematological benefits accompanying the adaptation to high altitude while allowing the athlete to maintain a quality training regimen in a sea level environment. Whether or not the altitude benefits can be achieved when exposures are limited to sleeping in a simulated high altitude (HA) environment is open for debate. PURPOSE To determine plasma (PV) and red cell (RBC) volumes and total hemoglobin mass (THb) responses in runners during 40 days of sleeping in a “nitrogen house” while maintaining a vigorous training regimen at sea level. METHODS Eight elite-level distance runners (age 23 ±6 yrs; VO2max 78.2 ±3.5 mL.kg−1.min−1) spent 8–10 hrs/night in HA ranging from 1980 to 3650 m; three controls (C) lived at sea level. The runners exposed to normobaric hypoxia and the C subjects trained at sea level throughout the experimental period. Blood volume and THb were determined by the CO method before and again after 41.7 ±5.9 days of HA. RESULTS Results are presented in the Table (mean ±S.E.; *p < 0.05). Initial and 40-day serum ferritin levels for the HA group averaged 75 ±45 and 68 ±40 ng·mL > −1, respectively. The significant increase in Hct with HA was the combined effect of slight increases (NS) in RBC and THb, and a decrease (NS) in PV. CONCLUSION Forty nights sleeping 8–10 hours in HA elicited both a significant fluid shift(hemoconcentration) and the suggestion of increases in RBC and THb. However, changes in the latter parameters were NS and the effectiveness of this regimen for increasing the oxygen carrying capacity of the blood remains equivocal.Table: No Caption Available