Keep in mind that you are traveling overland to highest plateau in the world; the drive goes constantly above 5000m during your journey except Lhasa (3,650m). Driving fast in such an elevation could cause medical conditions (Acute Mountain Sickness) which could be fatal. There is 50% less oxygen compared to sea level in high-altitudes places like in Tibet. The higher the altitude the less is the oxygen in air. Your body needs few days to acclimatize to this less oxygen environment. Although we provide enough information regarding AMS precaution matters, if you get AMS, we do not have other options to treat it other than medication. We advise specially the guest(s) with known heart or lungs or blood diseases to consult their doctor before traveling. Mild headaches, fever, loss of appetite or stomach disorder are symptoms of AMS.