A device (1, 1') for taking a sample of human respiration of a person exercising, comprising at least one first holding element (3, 3'), at least one sensor unit (19, 19') comprising a calibration component as well as at least one first sensor for determining an oxygen concentration of inspired and/or expired air of a user, and/or at least one second sensor for determining a carbon dioxide concentration of the inspired and/or expired air of the user, and/or at least one third sensor for determining the volume flow of the inspired and/or expired air of the user and, optionally, at least one fourth sensor for determining a heart rate of the user, and at least one funnel-shaped and/or tubular housing element (17, 17'), wherein the at least one first holding element comprises at least one transverse arm (5, 5'), wherein the at least one transverse arm is adapted and arranged to hold the device on at least one first holding point (13, 13'), in particular on a nose, the back of the head and/or the back of the neck of a user, and the at least one first holding element can be or is connected directly or indirectly, in particular via at least one second holding element (9, 9'), to the at least one funnel-shaped and/or tubular housing element, such that the at least one funnel-shaped and/or tubular housing element can be or is held in front of a mouth of the user, and wherein the at least one sensor unit can be or is connected to the at least one first holding element, the at least one second holding element and/or the at least one funnel-shaped and/or tubular housing element, wherein the at least one sensor unit is arranged inside of the at least one funnel-shaped and/or tubular housing element, wherein the sensor unit is adapted and arranged to measure an oxygen and/or carbon dioxide concentration in the inspired and/or expired air and/or a volume flow of the inspired and/or expired air and, optionally, to measure a heart rate of the user, while the at least one funnel-shaped and/or tubular housing element is held at a distance in front of the mouth of the user, such that a partially open volumetric space for the inspired and/or expired air is provided by the funnel-shaped and/or tubular housing element, such that the face of the person exercising is substantially not sealed to the outside. at least one first holding element (3, 3'), at least one sensor unit (19, 19') comprising a calibration component as well as at least one first sensor for determining an oxygen concentration of inspired and/or expired air of a user, and/or at least one second sensor for determining a carbon dioxide concentration of the inspired and/or expired air of the user, and/or at least one third sensor for determining the volume flow of the inspired and/or expired air of the user and, optionally, at least one fourth sensor for determining a heart rate of the user, and at least one funnel-shaped and/or tubular housing element (17, 17'), wherein the at least one first holding element comprises at least one transverse arm (5, 5'), wherein the at least one transverse arm is adapted and arranged to hold the device on at least one first holding point (13, 13'), in particular on a nose, the back of the head and/or the back of the neck of a user, and the at least one first holding element can be or is connected directly or indirectly, in particular via at least one second holding element (9, 9'), to the at least one funnel-shaped and/or tubular housing element, such that the at least one funnel-shaped and/or tubular housing element can be or is held in front of a mouth of the user, and wherein the at least one sensor unit can be or is connected to the at least one first holding element, the at least one second holding element and/or the at least one funnel-shaped and/or tubular housing element, wherein the at least one sensor unit is arranged inside of the at least one funnel-shaped and/or tubular housing element, wherein the sensor unit is adapted and arranged to measure an oxygen and/or carbon dioxide concentration in the inspired and/or expired air and/or a volume flow of the inspired and/or expired air and, optionally, to measure a heart rate of the user, while the at least one funnel-shaped and/or tubular housing element is held at a distance in front of the mouth of the user, such that a partially open volumetric space for the inspired and/or expired air is provided by the funnel-shaped and/or tubular housing element, such that the face of the person exercising is substantially not sealed to the outside.