The invention relates to a length-adjustable shaft comprising - an outer sleeve-shaped axial part; - an inner axial part which can be pushed into and deployed out of the outer axial part in a telescopic fashion and which encloses a buffer chamber; - having a bearing which is arranged between the two axial parts and which can be lubricated with a lubricant; - that end of the inner axial part which can be pushed into the outer axial part has an end wall; - a ventilation opening is provided which connects, in a conducting fashion, the buffer chamber to the cavity which is enclosed by the outer axial part. The invention is characterized by the following features: the ventilation opening comprises at least one bore which is offset with respect to the rotational axis of the shaft.