We present new results of a spectroscopic survey of circumstellar H i in the direction of evolved stars made with the Nançay Radiotelescope. The H i line at 21 cm has been detected in the circumstellar shells of a variety of evolved stars : AGB stars, oxygen-rich and carbon-rich, Semi-Regular and Miras, and Planetary Nebulae. The emissions are generally spatially resolved, i.e. larger than 4 ′ , indicating shell sizes of the order of 1 pc which opens the possibility to trace the history of mass loss over the past ∼ 10 4 − 10 5 years. The lineprofiles are sometimes composite. The individual components have generally a quasi-Gaussian shape; in particular they seldom show the double-horn profile that would be expected from the spatially resolved optically thin emission of a uniformly expanding shell. This probably implies that the expansion velocity decreases outwards in the external shells (0.1-1 pc) of these evolved stars.The H i line-profiles do not necessarily match those of the CO rotational lines. Furthermore, the centroid velocities do not always agree with those measured in the CO lines and/or the stellar radial velocities. The H i emissions may also be shifted in position with respect to the central stars. Without excluding the possibility of asymmetric mass ejection, we suggest that these two effects could also be related to a non-isotropic interaction with the local interstellar medium.