The changes in the control of breathing in man at high altitude have been studied at 5,800 m (19,000 ft). The differences between 1owlanders and Sherpas were compared at 4,880 m (16,000 ft.). Ventilatory response to C0\(_2\), hypoxia and exercise were studied, and acid-base status of the blood and CSF measured. Acclimatization to altitude is characterized by a shift of the C0\(_2\) response curve to the left and an increase in its slope. The hypoxic sensitivity appears unchanged. On moderate exercise there results a progressive increase in ventilatory equivalent with increasing altitude. At maximum work rate ventilation increases more rapidly due to falling Sao\(_2\). Sherpas show no significant difference in response to C0\(_2\) but a remarkable lack of response to hypoxia. The C0\(_2\) response showed little change in slope with change of P0 \(_2\) and on exercise acutely changing PO\(_2\)had little effect on ventilation. Sherpas ventilate less on exercise and have higher maximum 0\(_2\) intakes per kg than lowlanders. The arterial pH of highlanders is normal whereas in lowlanders it remains slightly elevated after k-6 weeks at altitude. CSF pH of highlanders is about 0.04 units more acid than lowlanders at the same altitude, indicating a greater central contribution to respiratory drive and a reduced peripheral component. The role of anaerobic cerebral metabolism in respiratory acclimatization is discussed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:583078 |
| Date | January 1968 |
| Creators | Milledge, J. S. |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/4510/ |
Page generated in 0.0121 seconds