Abstract: An expansion indicator device is used around a waist of a user to indicate whether a threshold amount of stomach cavity expansion is achieved as the user breathes and includes a strap, a power source, a feedback indicator and a switch assembly. The strap is fabricated from a stiff yet flexible material and is sized and adapted to be secured around the waist of the user. The feedback indicator is operative between an activation state whereby the power source is connected to the feedback indicator thereby energizing the feedback indicator and a de-activation state whereby the power source is disconnected from the feedback indicator thereby de-energizing the feedback indicator. The switch assembly interconnected to the power source and the feedback indicator and is operatively connected to the strap so that, as the user breathes, the switch assembly is operative to move between a closed condition and an opened condition.