High plasticity of temperament as a marker of flexible autonomic regulation of the cardiovascular system in urgent adaptive response to cold in young people

The properties of temperament are due to differences in the excitability of brain systems that integrate the behavior of an individual, his emotions and autonomic functions and play an important role in the adaptation of the body to the environment. The mechanisms of the relationship between individual characteristics of temperament properties and regulation of the cardiovascular system have not been fully elucidated. The aim of this study to assess the relationship between expression of temperament traits and the autonomic regulation of the cardiovascular system in the baseline condition and in response to exposure to cold. The study involved 25 healthy male volunteers aged between 18 and 21 years. Temperament traits were measured using the Structure of Temperament Questionnaire. During the study, heart rate variability (HRV) parameters (5 min), systolic and diastolic blood pressure (SBP and DBP) were recorded at room temperature. In the period from 5 to 10 min of exposure in an UShZ-25 N cold chamber (–20 °C), HRV were assessed. Immediately after the subjects came out from the cold chamber, blood pressure was measured. Then, 5 min after they left the cold chamber, SBP, DBP, HRV were recorded. The results showed that in young people with different expressions of temperamental properties, no differences were found in the regulation of heart rhythm by the autonomic nervous system in the baseline condition. The high object-related plasticity, i.e. the ease of switching from one type of activity to another, linked with autonomic flexibility and blood pressure control, which restrains a significant increase in blood pressure when exposed to short-term cold, and contributes to the preservation of health.