If you have a mountain near you, it’s good to ride a couple of times before going to the high mountains. Also do any kind of regular physical activities a couple of months before the trip like jogging, gym, cycling or anything similar that you prefer. That will get your endurance levels up and you will thank yourself once on the mountain. Of course, while skiing or snowboarding you will choose your own amount of time that you are able to spend on slopes. But it’s always nice to prove to yourself that you can do more than expected.