There is nothing worse than nearly crapping yourself while traversing an icy forty degree mountain pitch. I remember a climb recently that caused a member of my team major issues on his way up. His bowels would not stop releasing which in some moments endangered our four man tope team. He is a humble, yet a little prideful man who pushed on and completed his summit bid in absolutely pristine outdoor conditions. Had there been any external environmental challenges, we could have failed in our attempt or possible failed in staying safe.
Not to say the situation was completely dire, but it is a big issue for many mountain climbers of any elevation. There are many factors that play into this issue; however, two variables are most likely the major culprits: pre-existing conditions within the body or a poor choice in diet in recent days. Both serve equally in nearly any digestive stress, but when they encounter the stress of elevation conditions they become intensified.
Generally, everyone has a challenge in breaking down one of the three major nutrient (proteins, fats and carbohydrates) into usable constituents. If any exists, then eating a food high in any of them could lead to an issue pretty quickly, aka runny, brown ooze (Irritable Bowel Syndrome) or complete stoppage (Constipation). Fiber and water do not always do the trick, and the prior tends to be the major issue here. Being backed up is majorly uncomfortable, while uncontrollable poopage just shuts down normal function.
Determining which issue is the issue can take time, but with consistency it can change your world. First thing is remove one of the three major nutrients for a few days to see if any of the symptoms change. If you notice a change, look into potentially adding a corresponding digestive enzyme that breaks down the protein (protease), fat (lipase) or carbohydrate (amylase). These two actions can greatly improve the break down and give your body the opportunity to recover form trying to do the work itself. This is not always the simple answer. Actually most of the time it is not, but the basics work sometimes. Specific situations do exist where more specific assessments are needed to determine if other variables could be playing a factor. Visit with a digestive specialist (Me) to learn more.
Note: I am not a medical physician, and I do not prescribe or diagnose illnesses or diseases. My scope is limited to the function of the digestive system as it relates to food and digestive enzymes.