EXERCISE INDUCED CHANGES IN THE EQUINE ATHLETE'S HEART-DOES THE CLINICIAN NEED TO BOTHER?

摘要

Prolonged physical exercise induces dramatic changes in body composition and function. Luckily for all of us, the heart has a unique capacity for adapting to altered loading conditions. With increased oxygen demands during exercise the demand for blood flow is met by increased stroke volume as explained by Starling's law of the heart as well as increased heart rate (HR), both resulting in increased cardiac output. For the short-term, the heart can easily cope with the greater volume and/or pressure loads. However, when the overload is repeated or long lasting, a second mechanism becomes activated, leading to an altered expression of cardiac genes and an ensuing increase in ventricular muscle mass. Together with other cardiac changes, this physiological phenomenon is described in both human and equine athletes as the "Athlete's heart".