The vehicle seat (1) has a headrest (2). An upholstered part (5) of the seat back (3) contains a gas chamber (6) which is compressed by a load altering the shape of the seat. The chamber has a connection (4) to a gas cushion (8) in the headrest to carry air to the cushion when the chamber is compressed. In a rear-end crash, the mass of the body of the seat user exerts a load on the upholstered part of the back and on the gas chamber, compressing it and inflating the gas cushion.
