Here's the problem with Dr. Pepper. It has caffeine in it and caffeine restricts the blood flow and the blood flow is what carries the oxygen. That is the case with a lot of drinks when up high including drinking a lot of coffee. I'm not talking about one cup in the morning, but several will be bad for you. Tell him to switch to root beer for the trip. It does not have any caffeine in it.

Great info, as mentioned previously try to limit caffeine intake and hydrate with water. Caffeine can cause your blood vessels to constrict which will slow the amount of blood you can push through your body. Another thing to remember is the atmospheric pressure is reduced which makes the oxygen level less dense or harder to breathe in same levels you can at lower altitude. Those two things can make it feel like you're starving for air because you are moving less oxygen. Once you start getting tingling feeling in your hands, feet, nose or start having trouble seeing your body is telling you you're not getting enough oxygen, so rest if nothing changes move to lower altitude. Take the time to get acclimated and if possible have oxygen available in the event you have an emergency, if all else fails get to lower altitude.

So what yall are saying is Dr Pepper is the cure for altitude sickness. RIght on!