The invention relates to a sensor element (110) for determining at least one physical variable of a gas in a sample gas chamber (112), particularly for determining an amount of a gas component in an exhaust gas of an internal combustion engine. The sensor element (110) comprises at least one first electrode (114), at least one second electrode (118), and at least one solid electrolyte (116) connecting the first electrode (114) and the second electrode (118). The second electrode (118) is disposed in at least one electrode hollow space (120). The sensor element (110) comprises at least one gas access path (122), by way of which gas from the sample gas chamber (112) can be applied to the electrode hollow space (120). The gas access path (122) comprises at least one first section (124) having at least one porous flow barrier (126) and at least one second section (130) having at least one diffusion channel (136). The first section (124) and the second section (130) are connected in series. The first section (124) has a first diffusion resistance, and the gas access path (122) has a total diffusion resistance. The first diffusion resistance constitutes a portion of 20% to 80% of the total diffusion resistance.