Device features and design elements for long-term adhesion

An electronic device for long-term adhesion to a mammal, the device comprising:

• a housing comprising a physiologic data collection circuit, the housing positioned over a flexible layer comprising synthetic fibers, the flexible layer extending from beneath the housing and comprising an electrode positioned on an underside of the flexible layer distal from the housing, wherein the flexible layer comprises:
• a polymer upper layer overlying an electrical connection, the electrical connection extending linearly from the data collection circuit to the electrode when viewed from above the electronic device,
• an upper adhesive layer positioned under the polymer upper layer, the upper adhesive layer adhering the polymer upper layer to a polymer lower layer underlying the electrical connection, and
• a lower adhesive layer positioned on the underside of the flexible layer and extending from beneath the housing to the electrode, the lower adhesive layer configured to provide adhesion to the skin of the mammal.