Abstract: A magnetic muscle stimulator device comprises a water tank configured to hold a quantity of water, a pump, one or more fans, and a magnetic applicator comprising a coil. The coil generates a magnetic field in response to receiving an alternating current. The coil comprises a water passage in the interior of the coil. The pump receives water from the water tank through a first water pipe and transfers the water into the water passage of the coil through a second water pipe. The water absorbs heat from the coil while passing through the water passage of the coil. The pump receives the water from the water passage of the coil through a third pipe and returns the water into the water tank through a fourth pipe. The water is cooled by the fans while being returned from the water passage of the coil into the water tank.