April 19, 2017:
China has a serious problem in Tibet with altitude sickness among its troops and has had to bring in large quantities of special equipment to deal with it. This is mainly about coping when a lot more troops are brought in for an emergency like a major rebellion among the ethnic Tibetans or, more likely, a buildup for an invasion of adjacent Indian territory that is at a lower altitude. That means the Indian troops defending don’t have to worry about altitude sickness but the invading Chinese do, at least until the Chinese get down from the highlands.
To help Chinese troops cope troops new units arriving in Tibet will be able to rely on 165 oxygen generation stations, eight hyperbaric oxygen chambers (for dealing with severe cases), 12 mobile (on trucks) oxygen supply systems, nearly 5,000 small oxygen generators and nearly 7,000 oxygen cylinders that can be distributed as needed and refilled. Troops in the field will have access to a few minutes of oxygen as needed and for troops at bases bedside oxygen masks can also be provided. The Chinese Army is testing the distribution and use of all this equipment as troops arrive from the lowlands for training exercises in Tibet.
Altitude sickness occurs when people who grew up near sea level (most of the world's population) move to altitudes greater than 2,100 meters (7,000 feet). Below that, the air contains 21 percent oxygen. Above that, the percentage of oxygen declines, and that produces shortness of breath, disorientation, nosebleeds, nausea, dehydration, difficulty sleeping and eating, headaches and, if you stay up there long enough, chronic and long term disability. The average altitude of Tibet is 4,100 meters (14,000 feet).
What hurts you the most is the lower air pressure at higher altitudes, which means your lungs transport less oxygen to your blood. Most people can adapt, sort of. Some can't. But the Tibetans have evolved to deal with it. The majority of Chinese soldiers coming to the Tibetan highlands (which is most of Tibet) require a few days, or weeks, to acclimate. But they are still susceptible to altitude sickness if they exert themselves, especially for extended periods. This makes the troops much less effective. If a lot of troops are brought in and promptly sent into action there will be more troops suffering from altitude sickness.
Researchers recently discovered that most Tibetans evolved in the last 3-6,000 years to deal with this problem. It appears that the most of the people moving to, and staying in, highland Tibet, where those with the rare genes that made them resistant to altitude sickness. These people became the dominant population in Tibet, mainly because they were healthier at high altitudes. Nearly all Tibetans have this gene (which controls how their red blood cells operate, to maintain sufficient oxygen levels) while very few lowland Chinese do.
For nearly a decade now the Chinese military has been spending a lot of time, effort and money trying to solve this problem. Currently, most of the troops in the Chinese Chengdu Military Region are in the eastern, lowland half. In the western portion (Tibet), they station the 52nd and 53d Mountain Brigades, and struggle to keep these 5,000 troops fit for duty. If there's an emergency, as there was in 2008, the nearby 13th and 14th Group Armies can send troops from their lowland bases. Over 20 percent of these troops will be hampered by altitude sickness once they reach the highlands, and commanders are trained to deal with that. The new oxygen equipment program is designed to deal with that.
By 2010 Chinese troops operating at the highest altitudes (4,500 meters, on the Indian border) had access to exercise rooms (one of 1,000 square meters and another of 3,000 square meters) that are supplied with an oxygen enriched atmosphere. Troops exercising in these rooms increase the oxygen in the blood, and are much less likely to get hit with a case of altitude sickness. Thus the troops can stay in shape without getting sick. For border patrols at high altitudes, troops usually carry oxygen bottles and breathing masks.
So far, the Chinese have only been able to limit the attrition from altitude sickness, not eliminate it especially when it involves a lot of troops arriving for an emergency.