Runner's High May Also Strengthen Hearts
Endorphins and other morphine-like substances known as opioids, which are released during exercise, don't just make you feel good -- they may also protect you from heart attacks, according to University of Iowa researchers.
It has long been known that the so-called "runner's high" is caused by natural opioids that are released during exercise. However, a UI study, which is published in the online edition of the American Journal of Physiology - Heart and Circulatory Physiology, suggests that these opioids may also be responsible for some of exercise's cardiovascular benefits.
Working with rats, UI researchers showed that blocking the receptors that bind morphine, endorphins and other opioids eliminates the cardiovascular benefits of exercise. Moreover, the UI team showed that exercise was associated with increased expression of several genes involved in opioid pathways that appear to be critical in protecting the heart.
"This is the first evidence linking the natural opioids produced during exercise to the cardio-protective effects of exercise," said Eric Dickson, M.D., (photo, left) UI associate professor and head of emergency medicine in the Roy J. and Lucille A. Carver College of Medicine and the study's lead investigator. "We have known for a long time that exercise is great for the heart. This study helps us better understand why."