Altitude and Altitude sickness La Paz is at 13,000 feet, El Alto (where the airport is) is at 14,000 feet. Altitude sickness is a very real thing, don't let it ruin your trip. To help avoid altitude sickness try to start at a lower altitude and work your way up. I couldn't do thing and everything still worked out for me. I had a doctor prescribe some Acetazolamide (Diamox) and I think it helped. I also was diligent about working out and believe that helped. Be hydrated, rested and calm and get help if you need it. Don't go anywhere in a hurry your first few days, relax and stroll rather than stride. Everyone says that a few coca leaves do wonders, but I get drug tested at work and even though the leaves are not a drug, I"M SURE that they would show up in a test so that was a no-go for me. Even though I did not get sick, I really noticed the thin are the first day or two. Know the symptoms of altitude sickness and get medical help or reduce altitude if you get them; they are headache, dizziness, nausea, vomiting, fatigue and loss of energy, shortness of breath, problems sleeping, and loss of appetite; get help if you need it.