<human>:  What is high altitude sickness?
<bot>: High altitude sickness is a condition that occurs when a person is exposed to high altitudes. It is caused by low levels of oxygen in the blood. The symptoms include headache, nausea, vomiting, dizziness, and shortness of breath. It is important to take precautions to avoid high altitude sickness, such as avoiding strenuous exercise and drinking plenty of water.