A support column with a vertical tube has a coaxially installed gas spring including a cylinder divided by a piston into first and second working chambers. A piston rod passes through the second working chamber in a sealed manner to the outside, where it is attached to a bottom support piece of the vertical tube. The cylinder projects out of the vertical tube and is guided with freedom to slide back and forth in a guide sleeve installed in the end of the vertical tube opposite the bottom support piece. A connection between the first and second working chambers can be blocked by a manually actuatable valve. A second valve between the chambers, which is closed when the gas spring is under load, can be switched to the open position after the load on the gas spring has been absent for a certain period of time.