There are a few groups of people who should avoid high altitudes: People with heart or lung conditions: High altitudes can put extra strain on your heart and lungs. If you have a history of heart or lung problems, it’s best to avoid high altitudes. Pregnant women: Pregnancy puts extra strain on your heart and lungs, so it’s best to avoid high altitudes. Children: Children’s bodies are still developing, so they may not be able to handle the stress of high altitudes as well as adults. If you fall into one of these groups, talk to your doctor before planning a trip to a high altitude.