Rubbers exposed to high-pressure diffusive gas may exhibit cavitation during decompression, when the gas previously sorbed into the polymer expands faster than desorption out of the material. The present experimental study addresses the evolution of cavity field under repeated pressure cycles. A 2D optical method and a 3D approach based on in-situ tomography were applied to an unfilled EPDM exposed to hydrogen up to 15 MPa. The pressure cycle profile (decompression rate, duration of the desorption stage and intermediate pressure between two consecutive cycles) was changed in order to variably synchronize the mechanical hydrostatic pressure and the hydrogen gas content field, at different stages of the cavity growth.