Everything is quite simple, the atmospheric pressure and the adaptation of our body are to blame.
As you know, pressure drops with height by about 1 mm of mercury for every 15 meters of height (or 1 hPa every 8 meters). In total, at the height of Elbrus, the pressure is exactly two times lower than at sea level. And at an altitude of 10-11 kilometers it is approximately 95mm.
It is clear that such pressure is completely uncomfortable for passengers, therefore, excess pressure is pumped into the cabin and maintained at about 650mm r / s (corresponds to an altitude of 1500-2000 meters above sea level). Automation, alas, is imperfect, and the pressure in the plane, especially during takeoff and landing, jumps steps, because of this, and "lays" ears, a headache, especially for passengers sensitive to changes in atmospheric pressure.
What to do? You can take a pain reliever before the flight, or just sit out those 1520 minutes of getting up and down. With "stuffy" ears, the fight is quite simple - we close the nose and "blow through" the ears, like scuba divers.
To understand how to deal with this, let's first figure out why this is happening.
When you rise to an altitude, atmospheric pressure decreases, but the pressure in the middle ear remains the same and begins to press on the eardrum. Because of this, there is a feeling of congestion. Accordingly, to get rid of this feeling, you need to somehow equalize the pressure. The middle ear cavity is connected to the nasopharynx (where the pressure is equal to atmospheric) by the Eustachian tube, and with an increase in its lumen, the pressure will equalize. And you can increase the lumen of the Eustachian tube in the following ways:
Swallow often (to stimulate salivation for this, stock up on chewing gum or sucking candy).
If that doesn't work, try yawning widely.
If it still doesn't feel better, you can try to “blow out” your ear: close your mouth, pinch your nose with your fingers and exhale into it. But this is a pretty radical way, use it carefully.
Or you can just use earplugs before climbing to keep the pressure in your ear from dropping.
The eardrum is "to blame" for everything. In addition to the ear, which we have on the side of the face, there is also an internal one, which has an outlet to the respiratory tract, and on the other side it is limited by the eardrum. if there is less air on the inside (i.e. inside the head) than outside, then the difference in pressure on both sides of the membrane causes it to bend inward, and vice versa, if the air outside your head is more discharged than inside, then the membrane bends outward (but this rarely happens, basically the membrane bends inward). When the plane descends / takes off, the pressure rises / falls outside, but inside it is the same as it was some time ago, and the membrane bends inward. To get it back into position, you yawn reflexively, trying to balance the pressure outside and inside your ear. Like this :)