Peak oxygen uptake and regional oxygenation in response to a 10-day confinement to normobaric hypoxia

• 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 (FIO2 = 0.154) conditions. Oxygen uptake ((V) over dotO(2)), ventilation ((V) over dot E), and relative changes in regional hemoglobin oxygenation (Delta([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) over dotO(2peak) were similar pre and post in the EXP confinement, whereas (V) over dot(E) increased in the EXP post normoxic and hypoxic trials (P < 0.05). The exercise-induced drop in VL Delta[HbO(2)] was less in the post-than pre-EXP trial by 4.0 +/- 0.4 and 4.2 +/- 0.6 mMduring 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) over dotO(2peak), despite the enhanced VL oxygenation.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Physiology (hsv//eng)

Nyckelord

Altitude acclimatization

Cerebral frontal cortex

Exercise

Intercostal muscle

Near-infrared spectroscopy

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