Why biofeedback would help this problem: Many people with asthma have an unusual breathing pattern in which they take a deep breath and then breathe in and out with very shallow, rapid breaths rather than exhaling all the way. This prevents their being able to take reasonably deep breaths and leaves them chronically short of breath. Many workers consider it essential to train asthmatics not to barrel breathe. Pneumographic biofeedback is perfect for detecting and retraining this pattern. Asthmatics can be taught to recognize and correct abnormal interactions between heart rate variability and breathing. Correcting this abnormal relationship has been shown to reduce the symptoms of asthma.