An incentive spirometer is provided that allows a user to achieve Sustained Maximal Inspiration (SMI) through the use of helical tubes. Specifically, the incentive spirometer includes three chambers, wherein each chamber includes a ball traveling upwards through three helical tubes in sequential order and subsequently dropping down through a basket. Here, each of the helical tubes and corresponding baskets generally represent various levels of lung capacity achieved with repetitive use and operation of the incentive spirometer.