HeartMath has done numerous studies on the effect of positive emotions on stress, physiology and human performance. Many of these studies are available for viewing on either the HeartMath.com or the HeartMath Institute.org websites.
These studies have been published in prestigious journals including Stress Medicine American Journal of Cardiology, Preventive Cardiology Journal of the American College of Cardiology, Integrative Physiological and Behavioral Science and The Harvard Business Review.