Definition of Biofeedback Research Spotlight The databases often return hundreds of medical studies for a single wellness approach. This section summarizes a sampling of five studies – providing just a taste of the available research.  Biofeedback Improves Heart and Lung Function During SleepA small study (2013) indicated that heart rate variability biofeedback before sleep improves cardiorespiratory resting function during sleep.Access this Biofeedback study Biofeedback Effective…