You should have seen what going the other direction did for running. Coming from 10,000 feet and going to Boot Camp in San Diego, right around 8 feet.
I had a guy setting across from me in the chow hall one day and he was staring at me. I finally asked if I had a booger or something. He siad, "Don't you breathe?" I could do the 3 mile run and my legs got tired but I was never winded. I went back up there this Fall. It was the first time I have been back in a long time. I was shocked at how big it has become. The only thing in Silverthorne I recognized was the Mint Bar. The town has crossed the river. Back when I grew up there it was on the one side of the Blue only. The lake was also the lowest I have ever seen it, and by a lot.