14 years of fulltime traveling has seen us from sea level to 12K + a number of times. I'm a retired RN and hold degrees in biochemistry and physics. I know a couple of things :) Certainly, that 4K to 10K in a day can be a jolt to the system. It's all about taking it easy. Seriously.
Acclimate. Slowly. The 1st day when you really, really want to take that hike 'cuz it's so purty? Don't do it! Relax. Do as little as possible. Sit in a chair and just breathe. Deeply. Drink more fluids (plain water is best) than you think likely. 8 oz/hr is not too much. Your body will thank you tomorrow. And although that Rocky Mountain high might be inviting, stay off alcohol and caffeine for at least 48 hours.
You're welcome. :)