Controversies in altitude medicine

Two areas of controversy in altitude medicine are briefly reviewed. The first area concerns the prevention of acute mountain sickness (AMS) with acetazolamide. It is argued that for full prevention of AMS symptoms 500-750 mg a day is necessary, but that symptom attenuation may be possible with lower doses. The second concerns the study of the relationship between cerebral blood flow and acute mountain sickness. Multiple methodological problems can be identified; some are related to the experimental settings and some to limitations of the technical tools that are used to estimate cerebral blood flow. For the moment it remains unknown whether or not a change in cerebral blood flow is an etiological factor for the development of acute mountain sickness.