were slightly lower at 54±1.24 beats/min and higher at 1.12±0.03 s (р≤0.001). In addition, sympathotonic pigs were characterized by the largest amplitude of the distribution mode of 39.55±2.23% (р≤0.001). It was somewhat lower in normotonics 25.00±0.83% and the lowest in vagotonics 11.90±0.54% (р≤0.001). The greatest difference between the maximum and minimum value of the mode was in vagotonic animals (0.25±0.01 s, p≤0.001), slightly lower in normotonic animals (0.13±0.01 s) and the lowest in sympathotonic animals (0, 07±0.01 s, p≤0.05). In vagotonic animals, on the contrary, a lower heart rate (р≤0.001), a longer R-R interval (р≤0.001), a smaller amplitude of the mode (р≤0.001), a lower stress index, an autonomous rhythm index, an autonomous balance index (р≤ 0.001), a greater difference between the maximum and minimum value of the mode (Δx). Thus, taking into account the obtained results, pigs, depending on the influence of the tone of the autonomic nervous system, have differences in the activity of the cardiovascular system Research and study of the role of the autonomic nervous system in regulating the activity of the cardiovascular system in animals is relevant, as it will allow to deepen the existing knowledge about the vegetative regulation of the physiological functions of the pig body. The aim of the work was to study indicators of heart rate variability depending on the tone of the autonomic nervous system in pigs. Experimental studies were conducted on pigs. Three groups of animals were formed: normotonics, sympathotonics and vagotonics. On the basis of the conducted research, it was established that the normotonic animals had average values of the indicators that were studied in comparison with other experimental groups. In sympathotonic animals, a high heart rate of 95±1.41 beats/min (p≤0.001) and a low R-R interval intensity of 0.63±0.01 s (р≤0.001) were established. In vagotonics, these indicators
normotonics, sympathotonics, vagotonics, pigs, autonomic nervous system
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