A pressure support system configured to deliver a pressurized flow of breathable gas to the airway of a subject, the pressure support system comprising: a pressure generator configured to generate the pressurized flow of breathable gas; one or more sensors configured to generate output signals conveying information related to whether the subject is ready to receive breath stacking therapy; and one or more processors configured to execute computer program modules, the computer program modules comprising: a control module configured to control the pressure generator to generate the pressurized flow of breathable gas according to a pressure control therapy regime, an event module configured to determine breath stacking events based on the output signals breaching readiness threshold levels and thereby indicating that the subject is ready to receive breath stacking therapy, and a breath stacking module configured to, responsive to the determination of a breath stacking event, control the pressure generator to generate, only during an inhalation, the pressurized flow of breathable gas according to a breath stacking therapy regime, at a second pressure level higher than a pressure level at which the pressurized flow of breathable gas is generated during an inhalation according to the pressure control therapy regime. a pressure generator configured to generate the pressurized flow of breathable gas; one or more sensors configured to generate output signals conveying information related to whether the subject is ready to receive breath stacking therapy; and one or more processors configured to execute computer program modules, the computer program modules comprising: a control module configured to control the pressure generator to generate the pressurized flow of breathable gas according to a pressure control therapy regime, an event module configured to determine breath stacking events based on the output signals breaching readiness threshold levels and thereby indicating that the subject is ready to receive breath stacking therapy, and a breath stacking module configured to, responsive to the determination of a breath stacking event, control the pressure generator to generate, only during an inhalation, the pressurized flow of breathable gas according to a breath stacking therapy regime, at a second pressure level higher than a pressure level at which the pressurized flow of breathable gas is generated during an inhalation according to the pressure control therapy regime. a control module configured to control the pressure generator to generate the pressurized flow of breathable gas according to a pressure control therapy regime, an event module configured to determine breath stacking events based on the output signals breaching readiness threshold levels and thereby indicating that the subject is ready to receive breath stacking therapy, and a breath stacking module configured to, responsive to the determination of a breath stacking event, control the pressure generator to generate, only during an inhalation, the pressurized flow of breathable gas according to a breath stacking therapy regime, at a second pressure level higher than a pressure level at which the pressurized flow of breathable gas is generated during an inhalation according to the pressure control therapy regime.