What makes it so it's harder to run in higher elevation?

Question

I'm usually at only 100 feet above sea level. when I went to visit some family who are at 3600 feet above sea level I had my mom pull over the car like 2 miles before we got there so I could run the rest of the way since I was getting the feeling of needing to run from sitting in the car for so long but when I started running I was very disapointed in myself for not running like I usually can. I kept pushing myself to run but I got so out of breath it felt like I was gonna pass out, but then realized the elevation is a lot higher... can that really effect you that bad?

Answer 1

air is thinner in higher altitudes, so when you go higher up, then you will not be able to have as much air available to you

Answer 2

the air is thinner

Answer 3

It affects you a lot, the oxygen content in the air is a lot less, so you aren't getting as much as fast. If you stay long enough the number of red blood cells will increase and you will begin to improve.  This is a temporary gain, however, and once you return to normal elevation your red blood cell count will return to normal.

Answer 4

there's less oxygen in the air up there. You have to breathe harder/more rapidly to keep your body at the normal O2 levels.

Answer 5

Yup. The higher elevation you are the less oxygen there is in the air. That is one of the reasons you have to be in such good shape to climb Mount Everest and K2.