It will be more than just thin air in the mountain that you have to deal with. Downhill skiing can be very physically demanding, even for people with healthy lungs. The cold air also will aggravate your condition by causing your bronchioles to constrict further. If you are at the early stage of the disease, you can still train and prepare yourself for the trip, and have a good time. It is not going to be easy. Here is what you have to do.
1. If you smoke, quit.
2. Join a fitness center, and perform aerobic and resistance exercises at least 3 to 4 times a week. Get at least 30 minutes of aerobic exercise per workout.
3. Go on a healthy diet. Eat plenty of fruits and vegetables, lean cuts of meats, and avoid sugary foods.
4. Regular massage therapy can ease symptoms of COPD.
5. Get a physical with your doctor just before your trip, and bring all medications with you. I wish you the best of luck. http://best4health.net