Increase In SDNN Research Articles

Improved heart rate variability in postmenopausal women following short-term combined exercise training

Imbalances in cardiac autonomic nervous systems are associated with cardiovascular risk factors and poor cardiac outcomes. Heart rate variability (HRV) is a practical and reproducible measure of cardiac autonomic nervous system function. Exercise training promotes positive adjustments in HRV. However, previous studies have reported mixed results. Therefore, this study aimed to investigate the effects of short-term combined exercise training on heart rate variability in post-menopausal women. Thirty-four women aged 50-80 years, at least 12 months post-menopause, were divided into a control (CON) group and an exercise (EX) training group. The participants in the exercise group underwent a 2-week of combined exercise program consisting of aerobic, strength, flexibility, and balance exercises. HRV was recorded using an Actiheart device, before and after the final exercise intervention in a sitting position. The significant main effects of time and group were found in the parameter of SDNN (p time = 0.039; p group = 0.026). Post-hoc analysis showed a borderline increase in SDNN in the EX group (POST: 48.79 ± 17.88 VS 44.54 ± 17.39, p = 0.055). No significant change was observed in the CON group (POST: 35.55 ± 13.51 VS 33.17 ± 8.74, p = 0.288). Statistical analysis of other HRV components revealed no significant results (all P > 0.05). In conclusion, a 2-week of combined exercise training program, including aerobic, resistance, balance, and flexibility exercises improves global cardiac autonomic function in post-menopausal women. Keywords: combined exercise training, heart rate variability, blood pressure, menopause, and women

The influence of breathing exercises on the heart rate variability parameters of female medical students

We studied the influence of breathing exercises (BE) with an imposed rhythm on the dynamics of heart rate variability (HRV) parameters in order to study the nature of adaptive processes in the body of girls with different initial levels of total HRV. Heart rate, time indicators: SDNN, mNN, RMSSD, pNN50 - and spectral parameters: TP, HF and HFnu, LF and LFnu, LF/HF - as well as IVR and IN indices were evaluated. According to the level of SDNN, individuals with conditionally low and conditionally high levels of total HRV were identified - groups LV (40 (31; 47) ms) and HV (64 (58; 70) ms). At rest, HRV parameters in HV-girls were significantly higher than in the LV-subgroup. After BE, a significant increase in SDNN and TP was observed in the LV-subgroup, against the background of a decrease in HF and HFnu and an increase in LF and LFnu, and the LF/HF ratio after BE increased by 80%. In HV-girls after BE, an increase of 6% in heart rate was recorded, but not in total HRV parameters: a decrease in HF and HFnu was compensated by an increase in LFnu, as a result, the LF/HF ratio increased significantly by almost 1.5 times compared to the rest level. In LV-girls, the indicators of autonomic balance index (AVR) and stress-index (SI) were higher by 2.6–2.7 than in the HV-subgroup. After BE, a decrease of 24 and 19% in the parameters of AVR and SI was observed in the LV, but not in the HV-subgroup. Thus, the adaptation of the work of the heart to BE occurred in a similar way in LV- and HV-individuals, however, it differed in different adaptive costs of such an effort for LV- and HV-subjects.

The use of face masks and the impact on heart rate variability during baseline ECG

We compared electrocardiograms (ECGs) findings with one year difference between each other with and without use of face mask at the moment to be tested. The first ECG was done one year before without face mask, and the second ECG with a mask one year later after 3 months of mandatory use for epidemiological COVID-19 pandemic justifications in healthy youth elite athletes. Regarding heart rate variability (HRV), an increase in RMSSD was recorded when the test was performed with a mask (M): 108.5 ± 90 ms vs. No mask (NM): 72.9 ± 54.2 ms (p <0.002). And also an increase in SDNN, when the test was done with a M: 86.2 ± 47.2 ms vs. NM: 65.9 ± 43.5 ms (p <0.036). The results on ECG are consistent with the increasing predominance of parasympathetic regulation, which is responsible for regulation of the autonomic loop when the subject is using face mask.

Effects of prolonged working hours on heart rate variability in internal medicine physicians

Prior studies have utilized heart rate variability (HRV) as the assessment tools for psychological and physiological stress during 24-h shift. However, data regarding effects of prolonged working hours > 24 h on HRV are limited. We aimed to compare between pre- and post-call HRV among physicians who worked 24 plus 8 h. The study included 60 physicians in the internal medicine training. All subjects underwent Holter ECG monitoring for HRV assessment. We compared between HRV of an 8-h regular workday (8am to 4 pm) before on-call duty (pre-call HRV) and an 8-h workday after 24-h on-call duty (post-call HRV). The mean age was 26 ± 2.5 years. Mean total sleep time during on-call duty was 238.9 ± 88.3 min. In overall population, the time-domain and frequency-domain HRV parameters were not different between pre- and post-call day. However, the physicians reported their sleep time in the 1st quartile (< 180 min) had significant increase in SDNN, pNN50, high frequency (HF), and decrease in low/high frequency ratio (LF/HF). In contrast, the physicians reported their sleep time in the 4th quartile (> 307.5 min) had significant decrease in pNN50, LF, HF, and increase in heart rate. Multiple linear regression revealed total sleep time as an independent factor associated with pre- and post-call HRV alterations. More sleep during on call (> 5 h) was associated with HRV pattern suggesting both increased sympathetic activity and reduced parasympathetic activity, while less sleep (< 3 h) during on call was associated with post-call parasympathetic rebound HRV pattern.

The effect of CPAP therapy on heart rate variability in patients with obstructive sleep apnea

The aim of this study was to analyze the relationship between the initiation of CPAP therapy and HRV in patients with OSA. The study group consisted of 37 patients, aged 34–79 (mean 54.95 years) with OSA treated with CPAP. Two subgroups of patients were distinguished: less than severe (AHI < 30, n = 16) and severe OSA (AHI ≥ 30, n = 21). The second study was carried out around a month after the initiation of therapy. CPAP therapy caused the improvement in polysomnographic parameters, however, in most parameters in time and frequency analysis, there were no significant positive changes in parasympathetic tone. Moreover, in HRV time analysis, the reduced rMSSD and pNN50 parameters in the hours of night rest and rMSSD and SDSD during the 15-min N3 sleep period were noted. Especially, in the group with AHI ≥ 30, we observed significant decreases in rMSSD and pNN50 for the entire time. The changes were mainly for the night periods including the N3 sleep period, which is especially connected with sleep apnea (parameters: rMSSD, SDSD, and pNN50). In spectral analysis, the decrease in HF from the 15-min daily activity period and the N3 sleep period was observed. Inverse correlations were seen between the maximum, median, and mean positive airway pressure (PAP) and the change in rMSSD, SDNN, and SDSD, mainly during night hours and the N3 sleep period. Only in patients with AHI < 30 the increase in SDNN was observed in 15-min N3 sleep period. The beneficial increase in SDNN parameter from time analysis was observed only in one sleep period in less ill patients with OSA. The lack of significant changes was observed in the majority of the parameters of heart rate variability after initiation of CPAP therapy in a short observational time; however, the shift towards reduced HRV was observed in patients with AHI > 30, so the response to CPAP therapy may depends on the severity of the apnea. The results may suggest that a longer observational period is needed in such studies, and the problem is still not fully elucidated.

CORRECTION OF AUTONOMIC DYSFUNCTION IN OVERWEIGHT CHILDREN BY NORMALIZING BODY COMPOSITION.

The aim: To investigated the effect of a 3-month body weight correction program on the functional state of the ANS in children of primary school age who had an increased body mass index and signs of autonomic dysfunction. Materials and methods: 82 children aged 9 to 11 were examined. During 3 months, all examinees underwent a body weight correction course. Body composition was mea¬sured by the bioimpedance method using the body composition analyzer «TANITA-BC-601» (Japan). The functional state of autonomic regulation was assessed using heart rate variability (HRV) indicators obtained by recording standard 5-minute ECG intervals using the computer hardware and software complex "CARDIOLAB" (XAI-MEDICA, Ukraine). Results: Statistical processing of HRV indicators showed that 51 children (62.2%) had signs of autonomic dysfunction. In the first group, there was a statistically significant decrease in body weight (from 47.33±4.62 to 44.12±3.96), BMI (from 28.15±2.64 to 26.63±2.87), TFC (from 33.54±3.68 to 30.89±2.81), VF (from 7.056±1.814 to 4.817±2.017) with a simultaneous statistically probable increase in the FFM index (from 60.27±2.47 to 63.15±2,38). According to the time domain indicators of HRV, children in first group have increased the TP of autonomous heart rhythm regulation, as indicated by a statistically significant increase in SDNN from 38.43±6.39 ms to 51.65±7.19 ms (р<0.05); the activity of the sympathetic link of the ANS decreased according to AMo from 41.23±6.17% to 34.29±5.83% (р<0.05) and the intensity of autonomic regulation according to IS, which decreased from 116.3±31,6 units to 81.2±29.1 units (p<0.05). Conclusions: 3-month body weight correction program led to the elimination of signs of autonomic dysfunction in 43.9% of the examined persons.

Influence of an Early Mobilization Protocol on the Autonomic Behavior of Patients Undergoing Percutaneous Transluminal Coronary Angioplasty.

ResumoFundamento:Gráficos de recorrência (GR) permitem uma análise não linear da variabilidade de frequência cardíaca (VFC) e fornecem informações sobre o sistema nervoso autônomo (SNA).Objetivos:Avaliar se a mobilização precoce em pacientes submetidos a angioplastia coronária transluminal percutânea (ACTP) influencia os componentes quantitativos e qualitativos dos GR.Métodos:Um total de 32 participantes que foram submetidos a ACTP foram divididos entre um grupo de controle (GC - sem exercícios físicos) e grupo de mobilização precoce (GMP - com exercícios físicos) A frequência cardíaca batimento a batimento foi registrada utilizando um cardiofrequencímetro em ambos os grupos na admissão e na alta. Os índices lineares nos domínios de tempo e frequência foram analisados, bem como os índices não lineares obtidos pelos GR. O protocolo fisioterapêutico de mobilização precoce começou 12-18 horas após a ACTP. Um teste T não pareado bicaudal foi utilizado para as comparações, e p-valores <0,05 foram aceitos como significativos.Resultados:Ao comparar os dois grupos, na alta, o GMP apresentou um aumento no SDNN (23,55 ± 12,05 a 37,29 ± 16,25; p=0,042), índice triangular (8,99 ± 3,03 a 9,66 ± 3,07; p=0,014) e VLF (694,20 ± 468,20 a 848,37 ± 526,51; p=0,004), mas não apresentou alterações significativas na avaliação não linear. Além disso, na análise qualitativa dos GR, observou-se um padrão mais difuso e menos geométrico no GMP, indicando maior variabilidade, enquanto no GC, notou-se um padrão geométrico mais alterado.Conclusão:O protocolo de mobilização precoce promove uma melhoria no comportamento autonômico, conforme avaliado por VFC e GR, e pode ser considerado um procedimento útil para a melhor recuperação de pacientes submetidos a ACTP.

Effects of 12-week Pilates training program on cardiac autonomic modulation: a randomized controlled clinical trial.

Aim: To evaluate the effects of 12-week Pilates training program on cardiac autonomic modulation. Materials& methods: A randomized controlled trial of a 12-week Pilates training program was conducted. A total of 54 men were randomly allocated to either a control or a Pilates group. Initially, the RR intervals were captured for 20min for later analysis of heart rate variability (HRV). The training protocol was then initiated, in which the Pilates group performed 36 sessions of the Pilates method for approximately 60min each session, three-times a week, totaling 12 weeks. The control group was instructed to maintain their normal activities during this period. One week after the end of the training, the final evaluations were performed with the capture of RR intervals in both the groups. Linear indices in the time (SDNN and rMSSD) and frequency (low frequency [LF] and high frequency [HF]) domains, and the Poincaré plot (SD1 and SD2) were used. Nonlinear indices were also analyzed (approximate entropy and detrended fluctuation analysis). Descriptive statistics and generalized mixed models were performed. Results: There was a group effect for LF (ms2) and a time effect for SD2. There was a training effect observed by the time*group interactions in which an increase in global HRV indices was found for the Pilates group after 12weeks (SDNN: mean difference [MD] =9.82; standard deviation [SD] =18.52; ES=-0.514; LF [ms2]: MD=334.23; SD=669.43; ES=-0.547; SD2: MD=14.58; SD=24.28; ES=-0.693). Conclusion: A 12-week Pilates training program promotes significant improvement in global modulation of HRV in the Pilates group considering the significant increase in SDNN, LF (ms2) and SD2 indices. Trial registration number: NCT03232866.

Application of the heated oxygen-helium mixture in rehabilitation of military servicers with arterial hypertension at the ambulatory-polycinic stage

Background. The professional activity of military personnel is characterized by complexity, high requirements for the state of physical and mental health, therefore, maintaining health and professional longevity is a priority task for the law enforcement agencies of the Russian Federation.&#x0D; Aims. The purpose of the study was to evaluate the effectiveness of the use of heated oxygen-helium mixture (OHM) in the rehabilitation of military personnel with arterial hypertension at the outpatient stage.&#x0D; Methods. The study included 68 people aged 32 to 56 (43,7 4,1) years. The patients were divided into two groups: Group I (n = 33) practically healthy volunteers, Group II (n = 35) patients with a verified diagnosis: arterial hypertension of I and II degrees, low and medium risk, the duration of the disease ranged from 1,5 to 18 (6.3 1.3) years. All patients included in the study underwent a course of inhalation of a heated OHM (the temperature of the mixture in the mask was 50С). Breathing was carried out in a cyclic-fractionated mode: breathing with a mixture 5 minutes, then breathing with atmospheric air 5 minutes (one cycle), 3 cycles per procedure. The course of treatment consisted of 1 procedure per day for 10 days from the first day of the study. The clinical efficacy of restorative treatment was assessed in three stages before the start of therapy, after the 5th and 10th procedures according to the following indicators: assessment of vegetative status using indicators of heart rate variability; express diagnostics of the psychoemotional state using the SAN questionnaire (well-being, activity, mood); assessment of adaptation of the cardiovascular system to physical activity using Martine's test with 20 squats.&#x0D; Results. In the second group, positive dynamics was noted in the form of normalization of the autonomic status, an increase in the activity of the parasympathetic division of the autonomic nervous system (an increase in SDNN, RMSSD indicators to 55 [4868] and 40 [3851 msec, respectively), a decrease in the tone of the sympathetic nervous system (normalization of the coefficient vagosympathetic balance LF/HF up to 1.1 [0.741.5]). The indicators of the SAN questionnaire have increased, which indicates an improvement in the psychoemotional state of servicemen. Patients with arterial hypertension, had positive dynamics in the rate of adaptive processes of restoration of the cardiovascular system after exercise (recovery time is 3.0 0.5 after the course).&#x0D; Conclusions. The use of a course of inhalations of a heated oxygen-helium mixture in the rehabilitation of servicemen with arterial hypertension has demonstrated its effectiveness in normalizing the psychoemotional state and vegetative status. In order to prevent the progression of arterial hypertension, this method can be included in rehabilitation programs at the outpatient and polyclinic stage.

Sustained Attention and Types of Dynamics of Cardiovascular Reactivity during a Short-Term, Human Whole-Body Exposure to Cold Air

Background: Despite global warming and the improvement of personal protective equipment against unfavorable climatic factors, cold remains an important environmental challenge for humans. The aim of the work was to reveal the peculiarities of the dynamics of cardiovascular parameters in humans with short-term, whole-body exposure to cold air, depending on the parameters of voluntary attention. Methods and Results: The study involved 28 healthy male volunteers aged between18 and 21 years, born and living in Arkhangelsk. Testing to assess sustained attention parameters using the Toulouse-Pierón Attention Test with the measurement of the index of accuracy (C, units) (the ability to voluntary concentration) and processing speed (V, units), had been previously performed. Subsequent stages of the study included recording the studied parameters before (Stage 1), during 10-minute exposure to the cold air (Stage 2), and 5 minutes after cold exposure (Stage 3). The registration of indicators in Stages 1 and 3 was carried out indoors at an air temperature of +20 °C. The registration of indicators in Stage 2 was carried out in a cold chamber at -20 °C. Determining the body temperature in the ear canal (Tear, °C) and on the skin of the dorsum of the right hand (Tskin, °C) was performed using a B.Well WF-1000 medical electronic infrared thermometer. Parameters of blood pressure (SBP and DBP) and heart rate variability (HRV) were evaluated. As a result of cluster analysis, 2 groups were identified: Group 1 (n=14) and Group 2 (n=14). In Group 2, the index V was significantly lower than in Group 1(P=0.02). In Group I, Tskin in Stage 1 was significantly higher than in Group 2 (P=0.03). In Stage 2, Tskin decreased in both groups, but lower Tskin values (P=0.001) were recorded in Group 2 than in Group I. In Stage 2, there was a statistically significant increase in SBP in Group 2 (P=0.01). In Group 1, initial SDNN and all HRV spectral indices were significantly higher than in Group 2. In Stage 2, there was a significant increase in SDNN in both groups. However, in Group 2, we found a statistically significant increase in VLF in Stage 2 (P=0.01), while in Group I this indicator remained unchanged. In Stage 3, HRV parameters in Group 1 recovered to baseline values, while in Group 2, HRV parameters remained elevated relative to baseline values. Conclusion: Individuals with high processing speed and preserved attention span have higher vagal activity and skin temperature. When such individuals are exposed to cold, they experience a moderate increase in BP and baroreflex response. In persons with a reduced speed of information processing but with sufficient accuracy of attention, there is a more pronounced mobilization of regulation resources on the part of the cardiovascular, neurovegetative systems to maintain the core temperature of the body.

Medication management of autonomic nervous system disorders in adolescents with tuberculosis

To manage autonomic disorders in adolescents with tuberculosis, 100 people from 12 to 15 years old were examined and randomly divided into two groups: Group 1 received standard anti-tuberculosis therapy, and in Group 2, additionally to standard therapy, comprehensive treatment with Magne B6was used for 2 months, and then Valerian extract was used for another 2 months. For comparison, 50 healthy adolescents were examined. Before treatment, all adolescents with tuberculosis experienced a decrease in heart rate variability, a pronounced autonomic imbalance with the prevalence of sympathicotonia and overexertion of compensatory mechanisms. In Group 1, during the comprehensive treatment there were an increase in SDNN and Mo and decrease in AMo and tension index at rest. Active orthostatic test (AOT) was accompanied by a significant increase in SDNN, Mo and a decrease in AMo, which indicated an increase in the activity of the parasympathetic autonomic nervous system and decreased activity of the sympathetic autonomic nervous system. In the group receiving standard therapy, hypersympathycotonia persisted and manifested through significant (p &lt; 0.05) reduction in such parameters as SDNN, increased heart rate, AMo, and Mo shift to short intervals. Medication management resulted in the vegetative balance by increasing heart rate variability, reducing hypersympathicotonia, improving the autonomic support of the cardiovascular system at rest and during AOT.

Effects of exergames on heart rate variability of women with fibromyalgia: A randomized controlled trial

The objective of the present manuscript was to evaluate the effects of 24-weeks exergame intervention on the heart rate variability (HRV) of women with fibromyalgia. First, 56 women with fibromyalgia were assessed for eligibility. A total of 55 women fulfilled the inclusion criteria and participated in this single-blinded, randomized controlled trial. A 24-weeks of exergames were completed by the exercise group in the university facilities. It was focused on the mobility, postural control, upper and lower limbs coordination, aerobic fitness and strength. A total of 120 min per week, divided into two sessions of 60 min, was completed. A short-term 5 min record at rest was used to assess the HRV. Time (SDNN and RMSSD) and non-linear indexes (Higuchi´s Fractal Dimension, SD1, SD2, ln stress score, and SD1/SD2) of HRV were extracted. Fifty participants (achieving an 89.28% of adherence), recruited from the local fibromyalgia association completed the study. They were randomly divided into an exercise (age = 54.04[8.45]) and a control group (52.72[9.98]). Significant interaction (group*time) effects in SDNN, ln stress score, SD2, and SD1/SD2 ratio were found. The EG showed an increase of SDNN and a decreased ln stress score and SD2. The CG showed an increased ln stress score, SD1/SD2. In conclusion, 24-weeks of exergame intervention based on the tool VirtualEx-FM improved the autonomic control in patients with fibromyalgia. However, significant effects on Higuchi´s fractal dimension were not found. This is the first study using exergame as a therapy in women with fibromyalgia which has led to an improvement the autonomic balance in these patients.

Influence of the breathing methods of the heated oxygen-helium mixture on the indicators of variability of the heart rhythm and functions of external respiration in military servers with chronic obstructive

The purpose of the research was to study the effectiveness of using heated oxygen-helium mixture in the medical rehabilitation of patients with chronic obstructive bronchitis.&#x0D; Material and methods. The study included 68 patients aged 32 to 56 years (43.7 4.1 years). The first group (n = 33) contained of practically healthy volunteers and the second group (n = 35) of patients with a verified diagnosis: chronic obstructive bronchitis, moderate to moderate degree of obstruction, the duration of the disease ranged from 2 to 16 years (5.4 1.4). In both groups, heated oxygen-helium mixture was used (the temperature of the mixture in the mask was 50С). Patients of the second group 30 minutes before inhalation of the heated oxygen-helium mixture used short or long-acting bronchodilators. The study was carried out before the start of therapy, after 5, 10 procedures. Estimated indicators of heart rate variability and respiratory function.&#x0D; Results and conclusion. The use of heated oxygen-helium mixture allowed to increase the activity of the parasympathetic department of the autonomic nervous system and reduce the tone of the sympathetic department, normalize the functioning of the bodys regulatory systems. The research data showed an increase in SDNN, RMSSD, a decrease in LF/HF wave power, and a decrease in the centralization index. After the 5th breathing procedure of the heated oxygen-helium mixture, the second group showed an increase in external respiration function by an average of 16%, and after a full course, by 20%, which indicates an improvement in pulmonary ventilation and a decrease in the degree of obstructive disorders.&#x0D; The use of heated oxygen-helium mixture is a promising method that does not give complications, can reduce the severity of obstructive syndrome, helps to restore the bodys adaptive systems, and can be used as one of the methods in the comprehensive rehabilitation of patients with chronic obstructive bronchitis.

Analysis of 24-Hour Heart Rate Variability among Panic Disorder Patients without Previous Drug Treatment and Comorbid Disorders

One of the METHODS used to assess autonomic nervous system dysfunction in the etiology of panic disorder (PD) is heart rate variability (HRV). HRV is controlled by the sympathetic and parasympathetic (vagal) branches of the autonomic nervous system and reflects the capacity of autonomic stimulation by the parasympathetic system. The aim of this study was to evaluate heart rate variability (HRV) time domain parameters based on twenty four hour holter ECG analysis among drug-naive patients with panic disorder (PD) without any other medical and psychiatric comorbidity. The study group consisted of 41 patients with PD and 46 healthy controls. Participants were evaluated with SCID-1 for psychiatric diagnoses. Then Hamilton Depression Rating Scale (HDRS), Hamilton Anxiety Rating Scale (HARS), Panic Disorder Severity Scale (PDSS) and Clinical Global Impression Scale (CGI-S) were applied to participants. Twenty four hour Holter ECG outcomes were analyzed on a computer program and time domain parameters were evaluated. Among the parameters analyzed from HRV, SDANN was significantly higher (p <0.001); duration of RMSSD, NN50 and pNN50 were lower in PD group than the control group (p = 0.003, p = 0.005, p = 0.047, respectively). In the correlation analysis, there was a moderate negative correlation between CGI-S and NN50 and pNN50. In logistic regression analysis, the increase in SDNN was found to increase the probability of PD by 1.11 (95% CI, 1.010-1.209); the increase in SDANN was found to decrease the probability of PD by 0.892 (95% CI, 0.818-0.973), and the increase in pNN50 was found to decrease the probability of PD by 0.523 (95% CI, 0.342-0.801). The data obtained in our study confirm that there is a decrease in some HRV parameters like RMSSD, NN50 and pNN50 reflecting parasympathetic activity among patients with PD.

Heart Rate Variability and Performance of Commercial Airline Pilots during Flight Simulations.

Pilots undergo a variety of stressors that may affect their performance during all phases of flight. Heart rate variability (HRV) has been considered as a reliable indicator of the parasympathetic and sympathetic activities of human autonomic nervous system, which can be used to characterize the sympathetic stress response of pilots during flight. In this study, thirty active commercial airline pilots were recruited to fly three flight segments in a Federal Aviation Administration (FAA)-certified A320 flight simulator with each segment at a different carbon dioxide (CO2) concentration on the flight deck. The pilots performed a series of maneuvers of varying difficulty, and their performance was evaluated by FAA designated pilot examiners. The HRV metrics (SDNN, RMSSD and LF/HF ratio) of each pilot both before and during flight simulations were measured with a Movisens EcgMove3 sensor. The average SDNN, RMSSD and LF/HF ratio of the pilots during flight simulations were 34.1 ± 12.7 ms, 23.8 ± 10.2 ms and 5.7 ± 2.8 respectively. Decreased HRV was associated with aging, obesity and performing difficult maneuvers. Both CO2 exposure and HRV had an independent effect on the pilot performance, while their interaction was not significant. The generalized additive mixed effect model results showed that a pilot performed better on a maneuver when his stress response was lower, as indicated by higher SDNN and RMSSD and lower LF/HF ratio. An interquartile range (IQR) increase in SDNN (21.97 ms) and RMSSD (16.00 ms) and an IQR decrease in LF/HF ratio (4.69) was associated with an increase in the odds of passing a maneuver by 37%, 22% and 20%, respectively.

Normalization of heart rate variability with taurine and meldonium complex in post-infarction patients with type 2 diabetes mellitus.

The purpose of this study is to scrutiny the Dynamics of heart rate variability (HRV) in patients with PICS with 2nd type DM against the background of Taurine (TN) and meldonium (ME). The results of the investigations prove the decrease of the oxidative stress, which is basis of DACN, under the influence of sulfur-containing amino acid taurine (TN), and meldonium (ME) — a competitive inhibitor of gamma-butyrobetaine hydroxylase. Biochemical mechanisms of synergistic action of ME and TN are also described. The results of the studies of 98 patients with PICS and concomitant 2nd type diabetes mellitus were analyzed. They were distributed by simple randomization method into two groups, comparable according to age and sex: the main group (MG) (n = 68): and group of comparison (GoC) (n = 30). HRV was evaluated twice daily at the Cardiosense HMEGG system: at baseline and after 12 weeks of treatment. For the assessment of HRV the frequency and spectral parameters were used. While evaluating the different methods of treatment, their influence on the range of spectral and time indices of HRV was determined (p = 0.001 by the criterion of Kruskall-Wallis). It was learned that the combined application of ME and TN gives a statistically significant (p <0.01) increase of SDNN, HF at night, pNN — on 50% by day (p <0.01, p <0.001 and p <0.01 respectively), and statistically significant decrease in LF at night, compared to GHG.

Autonomic changes induced by pre-competitive stress in cyclists in relation to physical fitness and anxiety.

Cycling is a sport which requires great physical effort from athletes. The stress and anxiety of competition might interfere greatly with performance, by impacting the autonomic system. Physiological alterations, such as situations that irritate, frighten or excite the individual can cause a stress response, defined as a response of the organism to reestablish the homeostasis, regardless of its relationship to a sports situation. The aim of this study was to present data on the autonomic changes induced by precompetitive stress in cyclists and their relation with physical fitness and anxiety. Twelve healthy cyclists aged between 18 and 40 years, with previous experience in competition at the regional level, participated in the study. Heart rate variability (HRV) and physical fitness (body mass index, body fat and aerobic capacity) were measured 5 days before the Mountain Bike championship and remeasured 45 minutes before the start of the race (HRV and Anciety). Paired T test, effect size and correlational test were used. Cycling competition is a stressful situation capable of altering autonomic and hemodynamic parameters. We observed the increase in SDNN, reflecting an increase in sympathetic autonomic control. There were correlations between physical fitness with some autonomic parameters, while anxiety correlated with the years of experience in competition.

Heart rate variability changes as an indicator of decompression-related physiological stress

Many aspects of the physiological stress related to the exposure to the hyperbaric environment have been studied, but no research has been made to evaluate the impacts of scuba diving on heart rate variability (HRV). We investigated the effects of a simulated dive to 557 KPa (45 meters of salt water) for a 30-minute bottom time on the frequency and time domains estimators of HRV. Electrocardiogram records were obtained with superficial electrodes for 30 minutes before the simulated dive and, subsequently, for one hour after the dive. Each of these time-series was then subdivided into non-overlapping windows of 256 consecutive R-R intervals. A control group was submitted to the same protocol, breathing the same gases used in the simulated dive, while not being exposed to the hyperbaric environment. In the control group we observed a significant increase in SDNN (the square root of the variance of the R-R intervals), RMSSD (the square root of the mean squared differences of successive R-R intervals), and in two bands (high and low) of the power spectrum of frequencies. The subjects in the simulated dive presented only an increase in the low-frequency estimator without any further relevant changes in other estimators of HRV. This study suggests that the low-frequency increase without concomitant high-frequency increase might be an indicator of the physiological stress caused by decompression and that such a dissimilarity in responses might be correlated to the dive-related impairment of the endothelial function.

Acute effects of whole body vibration on heart rate variability in elderly people

BackgroundWhole body vibration (WBV) has been widely used as a modality for physical activity. In fact, WBV has been used for physical rehabilitation, and to improve muscle performance; but there is little information about its effects on heart rate variability (HRV). AimThe aim of this study was to evaluate the effect of vibration on HRV of the elderly using the vibratory platform. MethodsEleven older adults (7 men, 4 women), aged between 60 and 75 years, were subjected to WBV. The study consisted of a single session of WBV with volunteers standing upright for 10 min on the oscillating platform, with frequency of vibration set at 20 Hz (displacement ± 6 mm; orbital vibration). Pre (baseline) and post-WBV electrocardiograph signals were acquired using a cardiac monitor; and data were statistically analyzed using paired Student's t-test or Wilcoxon test, as appropriate. ResultsThe results demonstrated an increase in SDNN (standard deviation (SD) beat-to-beat, N–N intervals), rMSSD (square root of the mean squared difference of successive N–Ns) and pNN50 (proportion of N–N50 divided by total number of N–Ns) post WBV (p = 0.032, p = 0.024 e p = 0.044, respectively), compared to baseline. The present study thus demonstrated that time domain variables (i.e., SDNN, rMSSD, and pNN50) increase post WBV. ConclusionsOlder individuals are at high risk of developing cardiovascular diseases. As seen in the study, WBV improves HRV; and may help reduce risk of cardiac ailments. Moreover, WBV does not require extensive physical activity on the part of the participant. This makes WBV potentially beneficial to the elderly population. Further studies on WBV using different frequencies and training schedules may improve its applicability in clinics.

A Hybrid Signal Processing of RR Intervals from QTc Variation Searching Arrhythmia and Improving Heart Rate Variability Assessment in Acute Large Artery Ischemic Stroke.

Sudden death caused by abnormal QTc and atrial fibrillation (AF) has been reported in stroke. Heart rate variability (HRV) is reduced with missing beats of RRI during arrhythmic episode and abnormal QTc variation during acute stroke. In this study, we develop a hybrid signal processing by Pan Tompkins QRS detection and Kalman filter estimator for meaningful missing beats and searching AF with prolonged QTc. We use this hybrid model to investigate RRIs of Lead II ECG in thirty acute stroke patients with long QTc and AF (LQTc-AF) and normal QTc without AF (NQTc-nonAF) and then assess them by HRV. In LQTc-AF Kalman, higher mean heart rate with lower mean RRIs compared to NQTc-nonAF Kalman was characterized. LQTc-AF Kalman showed significant increase in SDNN, HF, SD2, SD2/SD1, and sample entropy. SDNN and HF associated with high RMSSD, pNN50, and SD1 reflect predominant parasympathetic drive for sympathovagal balance in LQTc-AF Kalman. Greater SD2, SD2/SD1, and sample entropy indicate more scatter of Poincaré plot. Compared with conventional Labchart, fractal scaling exponent of α1 (DFA) is higher in LQTc-AF Kalman. Remarkable complexity with parasympathetic drive in LQTc-AF Kalman suggests an influence of missing beats during stroke.