RESUMEN

We investigated the effect of hypoxic acclimatization per se, without any concomitant influence of strenuous physical activity on muscle and cerebral oxygenation. Eight healthy male subjects participated in a crossover-designed study. In random order, they conducted a 10-day normoxic (CON) and a 10-day hypoxic (EXP) confinement. Pre and post both CON and EXP confinements, subjects conducted two incremental-load cycling exercises to exhaustion; one under normoxic, and the other under hypoxic (F(I)O(2) = 0.154) conditions. Oxygen uptake (V˙O(2)), ventilation (V˙(E)), and relative changes in regional hemoglobin oxygenation (Δ([HbO(2)]) in the cerebral cortex and in the serratus anterior (SA) and vastus lateralis (VL) muscles were measured. No changes were observed in the CON confinement. Peak work rate and V˙O(2peak) were similar pre and post in the EXP confinement, whereas V˙(E) increased in the EXP post normoxic and hypoxic trials (P < 0.05). The exercise-induced drop in VL Δ[HbO(2)] was less in the post- than pre-EXP trial by 4.0 ± 0.4 and 4.2 ± 0.6 µM during normoxic and hypoxic exercise, respectively. No major changes were observed in cerebral or SA oxygenation. These results demonstrate that a 10-day hypoxic exposure without any concomitant physical activity had no effect on normoxic or hypoxic V˙O(2peak), despite the enhanced VL oxygenation.

Asunto(s)

Aclimatación/fisiología , Corteza Cerebral/metabolismo , Hipoxia/metabolismo , Consumo de Oxígeno/fisiología , Oxígeno/metabolismo , Esfuerzo Físico/fisiología , Músculo Cuádriceps/metabolismo , Adolescente , Adulto , Corteza Cerebral/fisiología , Estudios Cruzados , Ejercicio Físico/fisiología , Hemoglobinas/metabolismo , Humanos , Hipoxia/fisiopatología , Masculino , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiología , Oxihemoglobinas/metabolismo , Músculo Cuádriceps/fisiología , Espectroscopía Infrarroja Corta , Adulto Joven