Originally Posted by
rickair7777
The military goes on O2 at 10,000.
I personally see serious cognitive degradation around 14,000. But I ski and hike in the mountains so I'm used to physical activity up to 10 or 12.
If you are inactive, overweight, and/or a smoker, mild hypoxia at 7-9K might not be unusual. My wife falls asleep much over 8.
Cardio exercise should help, and also check to see if you have an iron deficiency.
I don't know how much is exercise and how much is predisposed. I have a good friend who spends the first couple days he's in the mountains practically bed ridden with altitude sickness. He's completed the Ironman in Hawaii and is in fantastic shape. On the other hand, I've experienced no symptoms while in great shape, or 30 pounds overweight as I am now up to about 9,000.
Exercise never hurts, but one of the other big contributors to hypoxia is dehydration. Make sure you're drinking tons of water. If I'm not running to the lav to take a leak at the end of each leg I'm not drinking enough water.