British Journal of Pharmacology: "Exercise as a drug: the pharmacological benefits of exercise."<br>Harvard Health Publishing: "Exercising to relax."<br>Journal of the American Physical Therapy Association: "Chronic Stress, Cortisol Dysfunction, and Pain: A Psychoneuroendocrine Rationale for Stress Management in Pain Rehabilitation."<br>Johns Hopkins Medicine: "The Truth Behind ‘Runner's High' and Other Mental Benefits of Running."<br>National Institute on Aging: "Four Types of Exercise Can Improve Your Health and Physical Ability."<br>Harvard Health Publishing: "Exercise is an all-natural treatment to fight depression."<br>National Institutes of Health: "Exercise Benefits Brain Function: The Monoamine Connection," "The neuroethology of friendship."