The effect of acetazolamide on breath holding at high altitude

The effect of altitude and acetazolamide on breath holding was studied in 20 individuals. Breath holding time was reduced progressively during ascent. There was an additional reduction in the acetazolamide group at low but not at high altitude. The initial difference between the two groups may have been related to a lower CSF pH when on acetazolamide. At high altitude the finding of similar breath holding times in the two groups may have been due to acclimatization in the placebo group.