For Tibet travel, you would worry about Tibet mountain sickness. Acute Mountain Sickness (AMS) is an illness that affects people who climb mountains or travel above 2500 meters altitude. It often occurs when your body cannot adjust to a high level of altitude. Because most places in Tibet Autonomous Region (TAR) are higher than this level, Acute Mountain Sickness (AMS), also called Altitude Sickness is the biggest health risk to tourists in Tibet. AMS is common at high altitudes due to the decreasing availability of oxygen. Most people will experience differing degrees of symptoms at high elevation.