1. Utilisation of the time constant calculated from heart rate recovery after exercise for evaluation of autonomic activity in horses
- Author
-
T, Hada, H, Ohmura, K, Mukai, D, Eto, T, Takahashi, and A, Hiraga
- Subjects
Atropine ,Male ,Physical fitness ,Propranolol ,Autonomic Nervous System ,Oxygen Consumption ,Heart Rate ,Physical Conditioning, Animal ,Heart rate ,Animals ,Medicine ,Heart rate variability ,Horses ,business.industry ,Parasympatholytics ,VO2 max ,General Medicine ,Training effect ,Autonomic nervous system ,Physical Fitness ,Anesthesia ,Exercise Test ,Female ,business ,medicine.drug - Abstract
Summary Reasons for performing study: Heart rate (HR) recovery immediately after exercise is controlled by autonomic functions and the time constant (T) calculated from HR recovery is thought to be an index of parasympathetic activity in man. Objectives: To investigate whether it is possible to evaluate autonomic function using the time constant in horses. Methods: Five Thoroughbred horses were subjected to a standard exercise test. Following pre-medication with saline, atropine and/or propranolol, the horses ran for 2.5 min at a speed of 8 m/sec at a 10% incline and T was calculated from HR after the exercise. Secondly, 7 Thoroughbred horses were then trained for 11 weeks and T and maximal oxygen uptake (VO2max) measured at intervals of 1 or 2 weeks. In 6 horses, T with atropine pre-medication was also measured before and after the whole training period. Furthermore, the HR variability at rest was evaluated by power spectral analysis at intervals of 3 or 4 weeks. Results: Time constant was increased by atropine and/or propranolol pre-medication, decreased with the progress of training and inversely correlated with VO2max during training (r = 0.43, P
- Published
- 2006
- Full Text
- View/download PDF