This method has been proven for preparing traveling to high plateau in Tibet, China.
The training:
First 20 days: Walk 5 to 10 kilometers (3.1 to 6.72 miles) every other day. Walk every day if the body is in shape.
Next 20 days: Walk 5 to 10 kilometers in fast paces. If the body in shape, increase the physical activity, like climbing a mountain.
Next 30 days: Walk 5 to 10 kilometers in fast paces while wearing a double mask to cut down oxygen intake. This is to simulate the low density of oxygen in high altitude.
When comes actual climbing, after reaching 3,000 meters, it is advisable to take a break for a night every 500 meters of ascending and go back down 500 meters and sleep for the night. Drink 3 to 4 liters of water to keep the body properly hydrated. The urine should be ample and clear. Breathing fast as in hyperventilating, can help increase oxygen intake.
If get sick, go back down. Lack of oxygen can cause the body to kick in histamine which in turn will dilate the blood vessels. Over dilating of blood vessels can cause health problem or can be life threatening. If the dilation is in the brain it can cause headache. Over dilation can cause leaks because blood vessels are not leak proof. Leaking can cause edema. Which can cause serious headache if the edema is in the brain. A person can drown in his/her own fluid accumulated in the lungs, if heavy leaks end up in the lungs.
An herb called hong jin tian (Rhodiola rosea) has been used for preventing high altitude sickness by improving the function of the body.
If the red blood cell count is low, use some herb formula to improve the count, like shi quan da bu tang, si wu tang, ba zhen tang etc. These formulae can be obtain in Chinese herb stores.