This one's pretty self-explanatory, so we will leave you with this delightful YouTube video!
High Altitude Flatus Expulsion (HAFE). “We would like to report our observations upon a new gastrointestinal syndrome, which we shall refer to by the acronym HAFE (high altitude flatus expulsion). This phenomenon was most recently witnessed by us during an expedition in the San Juan Mountains of southwestern Colorado, with similar experiences during excursions past. The syndrome is strictly associated with ascent, and is characterized by an increase in both the volume and the frequency of the passage of flatus, which spontaneously occurs while climbing to altitudes of 11,000 feet or greater. The eructations (known to veteran back-packers as “Rocky Mountain barking spiders”) do not appear to vary with exercise, but may well be closely linked to diet. The fact that the syndrome invariably abated on descent leads us to postulate a mechanism whereby the victim is afflicted by the expansion of colonic gas at the decreased atmospheric pressure of high altitude. This is somewhat analogous to the rapid intravascular expansion of nitrogen which afflicts deep-sea divers and triggers decompression illness. While not as catastrophic as barotrauma nor as debilitating as HAPE (high altitude pulmonary edema), HAFE nonetheless represents a significant inconvenience to those who prefer to hike in company.” Related content: Discoblog: NCBI ROFL: Finding the frequency of Fido’s farts. Discoblog: NCBI ROFL: It’s like a Brita filter for your butt. Discoblog: NCBI ROFL: ha ha poop