Aim: 

Alterations in blood chemistry, acid-base, electrolyte, lactate metabolism, and hydration status may be determinants of sleep disturbance, with frequent arousal in altitude.

Methods: 

The study population was six healthy male mountain marathon runners (age range, 37–44 years). Metabolic parameters were measured in capillary blood drawn from the ear lobes, in venous blood drawn from the brachial vein, and in urine. Sampling was done with subjects in the wakeful and the sleeping state at 122 m, on reaching an altitude of 2050 m, and then after 6, 30–31 and 38–41 hours of acclimatization at 3480 m.

Results: 

In brief, pO₂ and %SO₂ were lower at 2050 m and 3480 m than at sea level, and pO₂ was significantly higher after 38–41 hours than after 30–31 hours of acclimatization at 3480 m (P < 0.05). After ascent to 3480 m, %SO₂ decreased (P < 0.003). Compared to sea level values, pH increased at high altitude (P < 0.05), consistent with changes in pCO₂ and [HCO₃^-](P < 0.05). %SpaO₂ at a sleeping altitude of 3480 m was lower (P < 0.05) than at sea level. At high altitude, the % of W time and the DFA increased significantly, whereas NREM sleep, REM sleep, and TST time all decreased significantly (P < 0.05).

Conclusions: 

The study results confirm that the techniques used for evaluating most of the changes in blood chemistry, acid-base equilibrium, electrolyte, blood lactate and dehydration metabolism are fairly suitable for clinical assessment and for field research conducted at an altitude of approximately 3480 m.

SPONSOR FSA-SKY ORG –FIRST 2007