As a plane ascends or descends, the cabin air pressure changes but if you aren’t awake to pop your ears the pressure could damage your eardrums.
British pharmacist Angela Chalmers told Express: "A quick change in altitude affects the air pressure in the ear. This leads to a vacuum in the Eustachian tubes, which makes the ears feel blocked and sound dull.
"Try not to sleep during takeoff and descent as you will not be swallowing as frequently and this can lead to blocked ears."