An electrically-powered, hand-held device with a mouthpiece intended to be used to perform routine breathing exercises solely in response to changes in breathing resistance to: 1) train the muscles of respiration and improve breathing capacity; and/or 2) slow breathing rate to promote mind-body relaxation and reduce stress/anxiety. It consists of an air chamber with a resistance-creating valve, a mouthpiece, and an adjustable resistance digital control, and it may communicate with a smart device software app for data display; some types include a nose clip. It may be used in the home and healthcare facility. This is a reusable device.