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Changes in respiratory control after 5 days at altitude
Ron B Somogyi1, David Preiss, Alex Vesely
1Department of Physiology, University of Toronto, Medical Science Bldg, Room 3326, 1 Kings College Circle, Toronto, Ont., Canada, M5S 1A8.
Respiratory Physiology & Neurobiology
|January 18, 2005
Summary
High altitude exposure alters breathing control and acid-base balance. Studies show a lower carbon dioxide threshold and respiratory alkalosis, with pH corrected by increased albumin concentration.
Area of Science:
- Physiology
- Altitude Medicine
- Respiratory Control
Background:
- Understanding human physiological adaptation to high altitude is crucial.
- Chemoreflex control of breathing and acid-base balance are key regulatory systems affected by altitude.
Purpose of the Study:
- To investigate changes in chemoreflex control of breathing.
- To examine acid-base balance alterations after short-term altitude exposure.
Main Methods:
- Six healthy males resided at 3480 m for 5 days.
- Modified rebreathing tests assessed hypoxic and hyperoxic ventilatory responses.
- Blood samples analyzed for acid-base status using Stewart's quantitative chemistry.
Main Results:
- A significant fall in the partial pressure of carbon dioxide (PCO2) threshold for ventilation was observed.
- Respiratory alkalosis occurred, indicated by decreased resting end-tidal PCO2.
- Albumin concentration significantly increased, while strong ion difference remained unchanged.
Conclusions:
- Short-term altitude exposure lowers the chemoreflex threshold for breathing.
- Respiratory alkalosis is compensated by an elevated albumin concentration, influencing acid-base balance.