and so too does the pressure of air. Many different factors affect the density of air. Most measurably, as altitude increases, air becomes less dense, decreasing atmospheric pressure. Standard ...

Stay hydrated: “Drinking more will help. Your body is more stressed at altitude as it tries to maintain its regular function.

To maintain the pressure in the cabin equal to that at low altitude, even while the airplane is at 30,000 feet, the incoming air is held within the cabin by opening and closing an outflow valve ...