Mattress having a lying surface for a user, comprising - a foam-like, resilient mattress core and - a knitted spacer fabric arranged on the mattress core, - wherein the mattress core has a vibration cavity, which is provided and is designed such that a vibration device, comprising an unbalanced mass driven by an electric motor, can be arranged therein in order to generate vibrations in the mattress, - the width of the mattress is between 70 cm and 220 cm and - the length of the mattress is between 180 cm and 220 cm, wherein - the vibration device is in the form of a rod-shaped, cylindrical or tubular vibration rod in which the electric motor and the unbalanced mass as an eccentric body are arranged, - the length of the eccentric body is between 8 cm and 40 cm, preferably between 10 cm and 25 cm, - the mattress comprises at least one, preferably only one vibration rod, - the mattress core has a plurality of vibration cavities, each of which is designed for insertion of the vibration rod and to enclose the vibration rod, inserted therein, in its circumferential direction, and which are arranged in parallel with one another in the transverse direction of the lying surface in a region underneath the lying surface, in which region the lower legs of a user of the mattress lying supine on the lying surface are located when the mattress is used as intended, - the distance between two adjacent vibration cavities is between 15 mm and 45 mm, preferably between 20 mm and 30 mm, - the number of vibration cavities is between 5 and 15, preferably between 7 and 11, - the internal diameters of the vibration cavities are matched to the external diameter of the vibration rod such that the vibration rod can be form-fittingly or force-fittingly inserted into the vibration cavities, - and the vibration cavities are arranged over a region which extends at the foot end of the mattress in the longitudinal direction of the mattress over a region of which the lower end in the longitudinal direction of the mattress is at a distance of between 5 cm and 30 cm, preferably between 10 cm and 20 cm, from the lower end face in the longitudinal direction of the mattress and of which the upper end in the longitudinal direction of the mattress is at a distance of between 25% and 40%, preferably between 30% and 35% of the length of the mattress from the lower end face in the longitudinal direction of the mattress, - and so, in order to adjust the position of the vibration rod to the individual body measurements of the user and the lying position of the user on the lying surface, the vibration rod can be inserted into a vibration cavity which is located below the centers of the calves of the user. - a foam-like, resilient mattress core and - a knitted spacer fabric arranged on the mattress core, - wherein the mattress core has a vibration cavity, which is provided and is designed such that a vibration device, comprising an unbalanced mass driven by an electric motor, can be arranged therein in order to generate vibrations in the mattress, - the width of the mattress is between 70 cm and 220 cm and - the length of the mattress is between 180 cm and 220 cm, wherein - the vibration device is in the form of a rod-shaped, cylindrical or tubular vibration rod in which the electric motor and the unbalanced mass as an eccentric body are arranged, - the length of the eccentric body is between 8 cm and 40 cm, preferably between 10 cm and 25 cm, - the mattress comprises at least one, preferably only one vibration rod, - the mattress core has a plurality of vibration cavities, each of which is designed for insertion of the vibration rod and to enclose the vibration rod, inserted therein, in its circumferential direction, and which are arranged in parallel with one another in the transverse direction of the lying surface in a region underneath the lying surface, in which region the lower legs of a user of the mattress lying supine on the lying surface are located when the mattress is used as intended, - the distance between two adjacent vibration cavities is between 15 mm and 45 mm, preferably between 20 mm and 30 mm, - the number of vibration cavities is between 5 and 15, preferably between 7 and 11, - the internal diameters of the vibration cavities are matched to the external diameter of the vibration rod such that the vibration rod can be form-fittingly or force-fittingly inserted into the vibration cavities, - and the vibration cavities are arranged over a region which extends at the foot end of the mattress in the longitudinal direction of the mattress over a region of which the lower end in the longitudinal direction of the mattress is at a distance of between 5 cm and 30 cm, preferably between 10 cm and 20 cm, from the lower end face in the longitudinal direction of the mattress and of which the upper end in the longitudinal direction of the mattress is at a distance of between 25% and 40%, preferably between 30% and 35% of the length of the mattress from the lower end face in the longitudinal direction of the mattress, - and so, in order to adjust the position of the vibration rod to the individual body measurements of the user and the lying position of the user on the lying surface, the vibration rod can be inserted into a vibration cavity which is located below the centers of the calves of the user.