Controlled hyperventilation after training may accelerate altitude acclimatization.

To the Editor: On January 28, 2014, a group of 26 trekkers (aged 29 to 65 years), under the supervision of the authors, ascended one of the world’s highest mountains (Mt. Kilimanjaro, 5895 m) in 48 hours (Figure 1). While doing so, the group appears to have broken new medical ground, utilizing a new method to largely prevent, and as needed, reverse, symptoms of acute mountain sickness (AMS). Seemingly an unlikely group of people for such a feat, the group consisted of nonathletes with little or no prior climbing experience, inhabitants of low altitudes, some with typically handicapping diagnoses such as multiple sclerosis, rheumatoid arthritis, and metastasized cancer. The team was predicted by mountaineering experts to fail owing to those demographics. It was assessed at the highest risk for exhaustion and altitude sickness due to very rapid ascent (4500 m per day), high final altitude (44000 m), and unknown history of AMS (according to a recent literature review). To offset these significant disadvantages, the group received special training, including mindset coaching, cold exposure, and breathing technique practice, as previously described and currently under investigation