Abstract. This study aimsto investigate changes in heart rate variability (HRV)in military personnelwith concussions.Men who received a brain concussion as a result of a mine-explosive brain injury during the Russian-Ukrainian war were examined.The study included 30menwith mild traumatic braininjury (concussion, age 37.4±1.70years)and 32 healthy men (control, age 37.1±1.65 years) aged from 25 to 50 years, who were examined Blood pressure, heart rate and ECG measurements were taken from 10:00 to noon, in the supine and standing positions (within 5 minutes).HRV scores were calculated in the time domainand frequency domain. Inpeopleafter a concussion,there wassignificantly lower control in the values of SDNN, and TP which characterisethetotal powerof neurohumoral regulation of heart rate (p<0.05). The differences in the indicators characterizing vagal influences were especially pronounced: in patients with concussion, RMSSD and HF were lower than in controls. The activity ofthe baroreflex centreof the medulla oblongata, assessed by the spectral power of low-frequency waves (LF), in people with a concussion was significantlylower compared to controls (p<0.05). The sympathovagalbalance (LF/HF) in people after a concussion, compared with the control, is shifted towards the predominance of the sympathetic division of the ANS.The average BAin the group of people with conсussion was51,8±3,62years, and in the control group –40,84±2,38 years (p<0,05). The difference between BAand CAis14,4±2,18 yearsin the groupof people with contusion and3,75±2,12inthe control group (p<0,01). The data obtained in our study allow us to conclude that concussion may be a factor that disrupts autonomic regulation and accelerates ageing.
The body mass index was calculated. All subjects were instructed to avoid alcohol or caffeinated drinks after 10:00 pm. (22:00) the night before the examination. In addition, they refrained from smoking 1 hour before the measurement. Blood pressure (BP), heart rate and ECG measurements were taken from 10:00 to noon, in the supine and standing positions (at 5 minutes). During the ECG recording, the subject was instructed to breathe according to his normal rate. ECG registration was carried out using the ECG-recorder DiaCard (Solvaig, Ukraine). ECG and HRV analysis performed by DiaCard ECG-recorder v. 1.0.0.73. The duration of the QT interval was measured by recording ECG in the supine position at 5 minutes. HRV scores were calculated in the time domain and frequency domain : SDNN The standard deviation of NN intervals; variance of all NN intervals. RMSSD The square root of the mean of the squares of the successive differences between adjacent NNs; parasympathetic
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NN50 The proportion of pairs of successive NNs that differ by more than 50 ms; parasympathetic activity. TP Total power ( 0,40 Hz); variance of all NN intervals. VLF Power in a very low-frequency range (0,003-0,040 Hz); humoral influences. LF Power in the low-frequency range (0,040-0,150 ); sympathetic and vagal influences. HF Power in the high-frequency range (0,150-0,400 Hz); parasympathetic activity. LF/HF Sympathetic-vagal index.
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23 Note: the term "NN" is used in place of RR-interval ECG to emphasize the fact that the processed beats are "normal" beats The formula for calculating the biological age was obtained by the method of multiple stepwise regression. The indicators of BP, ECG and HRV were selected, which correlate as much as possible with age and little among themselves. Statistical processing of the obtained data was carried out with the help of Excel 2007 and Statistica 7 (StatSoft, USA) programs. Standard statistical procedures, including variation and regression analyses, were used. Results and discussion The average age and anthropometric data of the examined people are shown in Tab. 1. The average age and anthropometric data of the examined people Indicators Control N=32 Concussion N=30 Age, years 37.11.65 37.41.70 Height, cm 176.21.87 177.71.18 Body mass, kg 78.42.56 81.62.31 Body mass index, kg/m2 25.260.76 25.850.64
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Waist circumference, cm 87.51.77 89.81.62 The data presented in Table 1 indicate the absence of significant differences in age and anthropometric parameters in the two compared groups of men. The results of measuring BP, heart rate and HRV analysis in the studied persons, depending on the presence of a concussion, are shown in Tab. 2. Average values of indicators (Mm) of BP, QT and HRV in men after concussion compared with healthy men (control) Indicators Control N=32 Concussion N=30 Registration in the supine position Systolic blood pressure, mm Hg 1223.71 1293.22 Diastolic blood pressure, mm Hg 822.77 802,53 Heart rate beats per minute 652.07 722.42* QT, ms 3615.76 3686.98 SDNN, ms 45.752,92 34.12.59** RMSSD, ms 33.53,21 23.62.62* pNN50, % 12.72,27 5.461.93* P, ms2 2240256 1291208** VLF, ms2 714101 57291* LF, ms2 78198 46593* HF, ms2 74484 25181** LF/HF 1.050,22 1.850,31* Registration in a standing position
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