Migraine at Altitude – Is It Due to Hypoxia or Hypobaria?

Bolay and Rapoport present an intriguing perspective on the association of migraine with low atmospheric pressure. Their study highlights a commonly experienced migraine trigger in some parts of the world, such as Alberta in Canada, where the periodic occurrence of a Chinook wind affects barometric pressure significantly. Whether low atmospheric pressure can trigger migraine independently is, however, an interesting discussion point. Other variables might also be worthy of examination. High altitudes, such as the extreme altitude referenced in the article by Bolay and Rapoport, may complicate the association of low atmospheric pressure with the triggering of a migraine. The altitude where high-altitude headaches occur typically, forming an important element of acute mountain sickness, is anywhere above 2500 m in altitude among those not acclimatized as well as rapid ascenders. The hypobaric hypoxia suffered, along with the associated headache, renders it difficult to suggest the independent influence of low atmospheric pressure. This is because the high-altitude headache is caused by the hypoxia, and not by the low atmospheric pressure. Oxygen inhalation usually cures such a headache. This suggests hypoxia, rather than low atmospheric pressure, may cause the high-altitude headache. It could be contended, therefore, that altitudetriggered migraine and high-altitude headache are probably due to hypobaric hypoxia rather than low atmospheric pressure. Acknowledgment: I would like to express my sincere thanks to Dr. Buddha Basnyat, president of Mountain Medicine Society of Nepal, for his guidance and invaluable time in reading this letter.