Exercise-induced cardiac fatigue of equine endurance athletes

Projektleder: Lektor Rikke Buhl, e-mail: rib@sund.ku.dk

Athletes develop increased heart size due to chronic pressure and volume overload as a result of extended physical exercise. This physiological phenomenon has been described in both human and equine athletes as “Athlete’s heart”. In general, this is considered benign, but both in human and equine athletes reports of athletes dying during or after high intensity training contribute to the theory that athletes heart may predispose to cardiac arrhythmias with eventually can become fatal for the athlete.

Endurance horses represent a group of racehorses racing over longer distances (up to 160 km). The races are getting increasingly popular all over the world but from a welfare point of view these long races put an extreme stress on the horses and only a minority of the horses complete the races. Therefore increased knowledge about the physiological changes occurring in these horses during exercise is needed.

The proposed study will increase our understanding of how the heart responds to long term physical exercise and to study the “Athlete’s Heart” and development of arrhythmias during these extreme conditions. This knowledge will eventually enable veterinarians to monitor the cardiovascular system of these horses and to interrupt the participation of the horse before collapse or metabolic diseases occur and will eventually increase the welfare of horses.

The objectives of this study are to standardize and validate electrocardiographic recordings in endurance horses. Furthermore we want to describe the function of the equine heart during an endurance race regarding exercise-induced arrhythmias, heart rate variability, and release of myocardial markers into systemic circulation.

Perspective of the research

This study will enable us to continue and elaborate this interesting research field regarding “Athlete’s Heart”. The knowledge is limited both in human and horses and in the future understanding of exercise induced cardiac stress can be further clarified. It is our goal to expand the comparative and translational research within human and equine athletes.

Partners on the project

• PhD student Mette Flethøj Madsen, Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen.
• Associate Professor Jørgen Kanters, Department of Biomedical Sciences, Laboratory of Experimental Cardiology, Faculty of Health and Medical Sciences, University of Copenhagen.
• Professor Lisbeth Høier Olsen, Department of Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen