also depends on your red blood cell counts and whether

you have the small red blood cell issue.

Many Asians have small red blood cell symptom. I forgot the proper name that shows up on your blood test lab report. You dont feel a thing even if you have this, you only feel you may sometime become short of breath when you exert yourselve, or you seem lack of endurance - that is because your red blood cells being small, they dont carry enough oxygen like the normal size red blood cell, and you become deprived of oxygen during exertion.

I have this problem, discovered many years ago when the company I worked for offered a very thorough pysical for each employee as part of benefit package. My youngest brother also has this problem - he discovered this when he did a thorough blood test before he got married. My other siblings dont have the same problem.

That is why I know I wouldn't go climb mountain top - my body simply is not equipped for that, by genetics.