Abstract: Disclosed are implant and method for gradually restricting vascular blood flow in a host blood vessel. The implant N comprising an elongated body and at least one holding member. Implant body comprising a flow restricting portion enclosing a variable minimal internal diameter. Holding member is configured for restraining implant body to maintain the variable minimal internal diameter in a first minimal internal diameter, and to physically yield voluntarily after a first predetermined average duration of being continuously subjected to internal human body conditions, thereby releasing and allowing the implant body to elastically deform voluntarily such that the variable minimal internal diameter changes to a second minimal internal diameter, smaller than the first minimal internal diameter.