Relationship between arterial oxygen saturation and heart rate variability at high altitudes.
Autonomic nervous systems have important roles for survival of victims under hypobaric hypoxic condition. In the present study, we assessed the correlation between arterial oxygen saturation (Sp O 2 ) and heart rate variability (HRV) to identify the autonomic nervous responsiveness among trekkers at high altitude (n = 21). HRV was analyzed by the maximum entropy method. Sp O 2 among subjects at 3456 m (495 mm Hg) was 80% +/- 5% (mean +/- SD; range, 69%-93%). Sp O 2 and percentile entropy, and Sp O 2 and low-frequency variability, had positive correlation ( r = 0.455 and 0.518, respectively). Sp O 2 value among subjects with mountain sickness symptoms was not different from that among subjects without the symptoms. In conclusion, autonomic responses among high-altitude trekkers may be blunted under hypobaric hypoxic conditions. Deterioration of autonomic function measured by HRV might be more sensitive to hypoxia than clinical symptoms at high altitudes.
Saito
Shigeru
S
Department of Anesthesiology, Gunma University School of Medicine, Maebashi 371-8511, Japan. shigerus@showa.gunma-u.ac.jp
Tanobe
Kyoko
K
Yamada
Makiko
M
Nishihara
Fumio
F
D000328:Adult; D000531:Altitude; D000532:Altitude Sickness / Q000097:blood / Q000503:physiopathology; D001158:Arteries; D001342:Autonomic Nervous System Diseases / Q000097:blood* / Q000503:physiopathology; D001784:Blood Gas Analysis; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D000860:Hypoxia / Q000097:blood* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D012016:Reference Values
D010100:Oxygen