3.8 The effects of exercise
Cardiac disease is of most importance in the context of its effects on exercise tolerance. It is therefore logical to assume that examination of the animal during exercise is of value in assessing the significance of cardiac disease. Unfortuexamination of animals during and even after exercise is complicated by a number of factors. Only a limited range of tests can be performed during exerThere is also a tremendous difference in the fitness levels of different aniand it is often unwise to assume that cardiac disease is responsible for apparent exercise intolerance. Nevertheless, so long as the limitations are considered, examination of the horse during and after exercise is of considerable value in selected cases. In addition, in the UK, examination of horses after exercise forms part of the pre-purchase examination and may correctly or incorrectly lead to the suspicion of cardiac disease.
Very few veterinarians in practice will have the opportunity to subject animals to controlled exercise programmes such as those which are possible using a high-speed treadmill. In the field, facilities for evaluating horses at exercise may limit the value of any tests. There is little purpose in examining a racehorse which has poor racing performance in a small muddy field. The principal purpose of examinations at exercise is to evaluate any abnormal cardiac rhythm rather than to assess the exercise tolerance of the animal.
3.8.3 Heart rate
3.8.4 Standardised exercise tests