Deep breathing to prevent acute mountain sickness

Mountain sickness can effect even the fittest among us. It is so prevalent that there are myriads of studies showing the lowest effective dose of acetazolamide, as it has unwelcome side effects. While other studies have shown that ibuprofen is effective without the side effects, these authors wanted to see if they could prevent AMS with simple breathing techniques.

They chose to do it with an unusual group of study participants as well. Usually, you get relatively healthy people who you know can complete the activity. They instead chose to use a group of nonathletes, all of which had almost no climbing experience. Going from 1970 m to 5895 m is quite a challenge, even if the terrain isn’t terribly technical. Many had medical problems that would typically preclude them from study, such as MS, RA, and metastatic cancer. Needless to say, this is not a group most would expect to be able to climb the peak successfully.

And yet they did, doing so in only 48 hours, instead of the usual 96+ hour climb. Also of note, they had a 92% success rate, much higher than the 61% success usually achieved. None of their group had any symptoms of severe AMS, and the 4 that had moderate AMS based on the Lake Louise Scoring System subsequently went back down to mild AMS after a 30 minute “breathing session.” 1 patient did have suspected HAPE, that resolved with descent and nifedipine.

How did they achieve such great results? The authors state that they were using the Wim Hof method, named after Wim Hof, of course. This is defined as mindset coaching, cold exposure, and breathing technique practice. Their methods section, lacking as it is a letter to the editor, doesn’t mention how long they trained before the ascent, just that they did. Mr. Hof’s own website advertises a 10 week video course. Of note, there is another study about the anti-inflammatory effects of this method as well, and their training was only 10 days in length.

At face value, it seems like the training was effective. This is balanced with the nigh unbelievable nature of the claims made by Mr. Hof and other proponents of his method. While I don’t want to dismiss this completely, I would argue that further studies certainly need to be performed before I recommend this method. On the other hand, you can (apparently) learn the method for free, and if you want to try it and take pharmacologic backup on your next climb, then the harm in trying is likely very low.

Buijze GA, Hopman MT. Controlled hyperventilation after training may accelerate altitude acclimatization. Wilderness Environ Med. 2014 Dec;25(4):484-6. [PMID 25443751]

References

• Kox M et al. Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans. Proc Natl Acad Sci U S A. 2014 May 20;111(20):7379-84 [PMC4034215]
• Hensley J. Climbing? Having trouble sleeping? EBM Gone Wild
• Hensley J. A novel prevention for acute mountain sickness. EBM Gone Wild
• Hensley J. Acute mountain sickness is more than one syndrome. EBM Gone Wild
• Hensley J. Predicting altitude sickness? EBM Gone Wild