How hard is it to breathe on Mount Everest?

Related questions

1. How cold is it at the top of Mount Everest right now?
2. Why can't a helicopter fly to the top of Everest?
3. How fit must you be to climb Everest?
4. Has anyone got to the top of Mount Everest?
5. Do Sherpas use oxygen on Everest?
6. How much are Everest Sherpas paid?
7. Is it hard to climb Mt Everest?
8. Why do Sherpas climb Mount Everest?
9. How did Namgyal Sherpa die?
10. Has anyone died on Kilimanjaro?

Tags

1. #third
2. #tasks
3. #level
4. #requires
5. #become
6. #muscles
7. #breath
8. #breathing
9. #pulls
10. #harder
11. #extra
12. #atmosphere
13. #because
14. #increases
15. #tries
16. #effort
17. #everest
18. #require
19. #physical
20. #oxygen