1) cardio fitness (ability to do x amount of work)
2) altitude adaptation (ability to exist at altitude)
It takes from several days to several months to adapt to altitude, depending on exactly what you mean by adapt. The first 24-72 are the highest risk for altitude sickness (which can be life threatening).
1) cardio fitness (ability to do x amount of work)
2) altitude adaptation (ability to exist at altitude)
It takes from several days to several months to adapt to altitude, depending on exactly what you mean by adapt. The first 24-72 are the highest risk for altitude sickness (which can be life threatening).
Both factor into performance at altitude.