1.   They cut off circulation, made it harder to breathe during altitude changes, and wreaked havoc on varicose veins.

2.   Although the ride is gentle overall, you must expect a certain amount of turbulence and a few dramatic altitude changes.

3.   Puzzled by the sudden altitude change, air traffic controllers asked the crew for its condition.

4.   When you take such an abrupt climb up, the altitude changes.