Heart Rate Variability Research Articles

Pilot turning behavior cognitive load analysis in simulated flight.

To identify the cognitive load of different turning tasks in simulated flight, a flight experiment was designed based on real "preliminary screening" training modules for pilots. Heart Rate Variability (HRV) and flight data were collected during the experiments using a flight simulator and a heart rate sensor bracelet. The turning behaviors in flight were classified into climbing turns, descending turns, and level flight turns. A recognition model for the cognitive load associated with these turning behaviors was developed using machine learning and deep learning algorithms. pnni_20, range_nni, rmssd, sdsd, nni_20, sd1, triangular_index indicators are negatively correlated with different turning load. The LSTM-Attention model excelled in recognizing turning tasks with varying cognitive load, achieving an F1 score of 0.9491. Specific HRV characteristics can be used to analyze cognitive load in different turn-ing tasks, and the LSTM-Attention model can provide references for future studies on the selection characteristics of pilot cognitive load, and offer guidance for pilot training, thus having significant implications for pilot training and flight safety.

Orienteering Is More than Just Running! Acute Effect of Competitive Pressure on Autonomic Cardiac Activity among Elite Orienteering Athletes.

Background and Objectives: Orienteering is a sport characterized by high physical exertion and intense mental demands, which increase susceptibility to errors. Understanding the impact of such errors on psychophysiological responses, particularly on heart rate variability (HRV), is essential. This study aimed to investigate the relationship between psychophysiological indicators and checkpoint errors made by elite orienteers during official competition. Materials and Methods: Fifty-three orienteers participated in this study, and their performance was continuously monitored and recorded by using a global positioning system (GPS) and HRV data. Errors made during the orienteering events were identified and analyzed. HRV data were examined in three temporal segments: before, during, and after the identified and standardized errors. Results: The analyses indicated that errors significantly impacted HRV indices across multiple domains: the time domain, frequency domain, and nonlinear domain. Additionally, a significant effect of sex on the normalized the root mean square of successive differences (r-MSSD) before and after the error was observed. Conclusions: The findings of this study underscore the significant impact of errors made by orienteers on cardiovascular responses, as evidenced by measurable alterations in HRV metrics. Cardiovascular activity, represented by the HRV, can provide useful information for coaches and sport psychologists to adopt effective training programs for athletes.

Influence of autonomic nervous dysfunction on eating during hemodialysis sessions: An observational study.

Although some studies have indicated that eating during hemodialysis may induce hypotension and cardiovascular events, some patients still consume food during their treatment. This prospective study was conducted to determine whether the need to eat during hemodialysis treatment was related to abnormal glucose metabolism and autonomic nerve dysfunction. Seventy patients were enrolled in this study, and their demographic features and various laboratory parameters were analyzed. At each routine hemodialysis visit, predialysis, intradialysis, and postdialysis blood pressure measurements were systematically conducted. A 24-hour ambulatory electrocardiogram (ECG) was performed during the hemodialysis interval, and heart rate variability (HRV) values were calculated. Additionally, whether the patients ate during the hemodialysis treatments was recorded. Another 20 people who underwent physical examinations during the same period and were matched for sex and age were included in the control group. The HRV values of the hemodialysis patients were generally lower than those of the control group. Univariate analysis revealed significant differences in sex, age, calcium antagonist use, blood calcium levels, insulin levels, diastolic blood pressure (DBP) measurements, and HRV indices between hemodialysis patients who ate and those who did not eat during hemodialysis (P < .05), whereas there were no significant differences in diabetes status or in the hemoglobin, albumin, blood glucose and C-peptide levels (P > .05). Multivariate analysis revealed that low values for very low frequency (VLF) and postdialysis DBP were risk factors for fasting intolerance during hemodialysis treatments. Autonomic dysfunction may affect whether hemodialysis patients tolerate fasting during dialysis. VLF evaluation may provide information that can be used to develop a more reasonable intradialytic nutritional supplementation method.

Elevated correlations in cardiac–neural dynamics: An impact of mantra meditation on stress alleviation

Mantra meditation is a widely practiced technique with a demonstrated ability to promote relaxation and alleviate stress. This study aims to evaluate the impact of regular mantra meditation practice on electroencephalogram (EEG) patterns and heart rate variability (HRV) in young adults grappling with increased stress levels. Furthermore, the study explored possible correlations between these two physiological markers. Thirty-eight participants practiced mantra meditation for eight weeks, and their EEG and HRV were recorded before and after. The pre-post analysis evaluated brain activity and autonomic nervous system regulation alterations by examining EEG and HRV in the time, frequency, and nonlinear domains. Data analysis revealed significant correlations between EEG patterns and HRV indices following mantra meditation, suggesting a potential interconnection between neural and cardiovascular regulation. A notable increase in Root Mean Square of Successive Differences (RMSSD) and Standard Deviation of NN intervals (SDNN) within HRV, along with a decrease in Heart Rate (HR) and Stress Index (SI) and an increase in EEG alpha and theta power, accompanied by a reduction in their ratio, was observed. Three pivotal correlations consistently increased during eight weeks: Alpha/Theta Ratio (ATR) with Low-Frequency/High-Frequency Ratio (LHR), ATR with SD2/SD1 Ratio (SDR), and Relaxation Index (RI) with Stress Index (SI). After eight weeks, these correlations attained statistical significance, optimizing the balance between calmness and vigilance, boosting parasympathetic activity, and reducing chaos between the parasympathetic and sympathetic systems. The study elucidates the scientific mechanisms of mantra meditation, enriching research on its stress-reducing effects and emphasizing mental and physical well-being.

Low-intensity focused ultrasound combined with microbubbles for non-invasive downregulation of rabbit carotid body activity in the treatment of hypertension.

Targeting the carotid body (CB) is a new approach in treating hypertension. This study investigates the efficacy and safety of ultrasound combined with microbubbles in targeting CB to treat hypertension. Twenty-seven hypertensive rabbits were randomly assigned to three groups: microbubbles only (sham group, n = 11), ultrasound plus microbubbles (LIFU group, n = 11), and bilateral carotid sinus nerve denervation (CSND group, n = 5). Four weeks post-intervention, blood pressure, hypoxic ventilatory response (HVR), blood pressure variability (BPV), heart rate variability (HRV), biochemical indicators, neurohormones, and histopathology were assessed in all groups. The results indicated significant reductions in systolic and diastolic blood pressure in the LIFU and CSND groups post-intervention, along with decreases in BPV, HRV, and catecholamines. HVR results showed a 35.10% reduction in CB activity in the LIFU group compared to the sham group, which was significantly lower than the reduction in the CSND group compared to the sham group (73.85%). Histopathology and transmission electron microscopy confirmed CB damage and cell apoptosis, with immunofluorescence showing a reduction in type I and II cells. In conclusion, LIFU combined with microbubbles can reduce blood pressure by lowering CB and sympathetic nerve activity.

Long-term effects of siponimod on cardiovascular and autonomic nervous system in secondary progressive multiple sclerosis.

Siponimod, a second-generation, selective sphingosine 1-phosphate receptor (S1PR) 1 and 5 modulator, represents an important therapeutic choice for active secondary progressive multiple sclerosis (SPMS). Besides the beneficial immunomodulatory effects, siponimod impacts cardiovascular function through S1PR1 modulation. Short-term vagomimetic effects on cardiac activity have proved to be mitigated by dose titration. However, long-term consequences are less known. This study aimed to investigate the long-term impact of siponimod on cardiac autonomic modulation in people with SPMS (pwSPMS). Heart rate variability (HRV) and vascular hemodynamic parameters were evaluated using Multiple Trigonometric Regressive Spectral analysis in 47 pwSPMS before siponimod therapy and after one, three, six and 12months of treatment. Autonomic activation tests (tilt test for the sympathetic and deep breathing test for the parasympathetic cardiac modulation) were performed at each examination. pwSPMS preserved regular cardiovascular modulation responses during the autonomic tests reflected in the variation of several HRV parameters, such as RMSSD, pNN50, total power of HRV, high-frequency and low-frequency bands of the spectral domain or hemodynamic vascular parameters (Cwk, Zao, TPR, MAP) and baroreflex sensitivity (BRS). In the long-term follow-up, RMSSD, pNN50, total power, BRS and CwK presented a significant decrease, underlining a reduction of the parasympathetic and a shift towards sympathetic predominance in cardiac autonomic modulation that tends to stabilise after 1year of treatment. Due to dose titration, the short-term effects of siponimod on cardiac autonomic modulation are mitigated. The long-term impact on cardiac autonomic modulation is similar to fingolimod. The autonomic activation tests showed normal cardiovascular responses during 1-year follow-up in pwSPMS, confirming the safety profile of siponimod. Further research on autonomic function could reveal whether the observed sympathetic activation is a compensatory response to S1P signaling intervention or a feature of the disease, while also shedding light on the role of S1PR modulation in MS.

Predicting sleep based on physical activity, light exposure, and Heart rate variability data using wearable devices

Objective We aimed to improve the performance of sleep prediction algorithms by increasing the data amount, adding variables reflecting psychological state, and adjusting the data length. Materials and Methods We used ActiGraph GT3X+® and Galaxy Watch Active2™ to collect physical activity and light exposure data. We collected heart rate variability (HRV) data with the Galaxy Watch. We evaluated the performance of sleep prediction algorithms based on different data sources (wearable devices only, sleep diary only, or both), data lengths (1, 2, or 3 days), and analysis methods. We defined the target outcome, ‘good sleep’, as ≥90% sleep efficiency. Results Among 278 participants who denied having sleep disturbance, we used data including 2136 total days and nights from 230 participants. The performance of the sleep prediction algorithms improved with an increased amount of data and added HRV data. The model with the best performance was the extreme gradient boosting model; XGBoost, using both sources combined data with HRV, and 2-day data (accuracy=.85, area under the curve =.80). Conclusions The results show that the performance of the sleep prediction models improved by increasing the data amount and adding HRV data. Further studies targeting insomnia patients and applied researches on non-pharmacological insomnia treatment are needed.

Variation of Seismocardiogram-Derived Cardiac Time Intervals and Heart Rate Variability Metrics Across the Sternum

Abstract Cardiac time intervals (CTIs) are vital indicators of cardiac health and can be noninvasively assessed using a combination of electrocardiography (ECG) and seismocardiography (SCG), a method of capturing cardiac-induced chest vibrations via accelerometers. SCG signals can be measured from different chest locations. However, more investigations are needed to evaluate the impact of sensor placement on SCG-derived cardiac parameters. This study investigates the effect of accelerometer placement along the sternum on SCG-derived CTI estimations and heart rate variability (HRV) parameters. A semi-automated algorithm was developed to detect SCG fiducial points and seven CTIs from thirteen healthy individuals. Comparative analysis with manually selected peaks and gold-standard ECG was conducted to assess fiducial point detection accuracy. Results indicate the highest recall and precision in aortic valve opening (0.84–1.00 and 0.96–1.00, respectively) and mitral valve closure (0.77–1.00 and 0.93–1.00, respectively) detection. Aortic valve closure (0.43–1.00 and 0.61–1.00, respectively) and mitral valve opening (0.64–1.00 and 0.91–1.00, respectively) detection, although slightly less accurate due to signal intensity variations, demonstrated overall effectiveness compared to manually selected peaks. Furthermore, SCG-derived heart rates showed a high correlation coefficient (r &amp;gt; 0.9) with the gold-standard ECG heart rates. Single-factor ANOVA revealed significant differences (p &amp;lt; 0.05) in SCG-derived CTI estimations based on sensor locations on the sternum, highlighting the importance of sensor placement for accurate assessments.

Correlation properties of heart rate variability for exercise prescription during prolonged running at constant speeds: A randomized cross‐over trial

Correlation properties of heart rate variability for exercise prescription during prolonged running at constant speeds: A randomized cross‐over trial

Electrophysiological detection of exam stress inhealth schools' students.

Anxiety is a common issue among university students, many of them experience anxiety, depression, and stress during their school life. This study aimed to compare the acute physiological stress responses of students divided into two groups according to their perceived anxiety levels (positive test anxiety, PTA+, and negative test anxiety, PTA-). Heart rate variability (HRV) and electrodermal activity (EDA) were used to assess stress.Thirty-one healthy volunteers participated in the study. Participants completed anxiety assessments, including the Westside Test Anxiety Scale (WTAS), the State-Trait Anxiety Inventory (STAI), and the Test State Anxiety Inventory (TSAI). Based on their scores, participants were categorized into PTA+ and PTA- groups. All participants underwent 24-h continuous recordings of pulse and electrodermal activity (EDA) on two separate occasions: one day prior to a written exam and during a designated exam-free day serving as a baseline control.We compared the HRV and EDA data obtained on a regular day and on an exam day between the two groups. Results showed that the PTA+ group had significantly higher heart rate, stress index, low frequency, and short-term detrended fluctuation analysis (DFAα1) on the exam day. The tonic EDA component was also higher in the PTA+ group. Stress-related HRV and EDA parameters were negatively correlated with exam scores.In conclusion, the study found that physiological stress indicators obtained from HRV and EDA are associated with perceived exam anxiety in students.

Effects of Physical Therapy Integrated with Dance/Movement Therapy on Heart Rate Variability and Fall-Related Variables: A Preliminary Controlled Trial

AbstractFalls among older adults are influenced by both physical and psychological risk factors. This pilot study specifically examined the impact of integrating Dance/Movement Therapy (DMT) into a regimen of physical therapy exercises (PTE) for fall prevention. The primary objectives included examining the effect of post-PTE+DMT intervention on heart rate variability (HRV), a psychophysiological marker, and fall risk factors. Additionally, this study aimed to examine correlations between HRV and levels of fall risk. Eight community-dwelling older adults (median = 83 [interquartile ranges: 80.5–85.75]) from a day center for senior citizens were randomly assigned to either a PTE+DMT group or a PTE group. A post intervention battery of HRV, physical and psychological fall risk assessments, was conducted. The results of nonparametric analysis demonstrated the potential impact of the PTE+DMT intervention in improving balance and self-efficacy measures related to falls when compared to participation in PTE alone. No statistically significant differences were observed between the groups in term of HRV and other physical and psychological fall risk factors. The emerging trends in the associations between HRV, fall risk, and balance levels suggest the potential utility of HRV as an objective psychophysiological marker for assessing fall risk levels. Moreover, the results underscore the potential advantages of interventions that integrate both physical and psychological components to mitigate fall risk in older adults, emphasizing the intricate mind–body connection.The ClinicalTrials.gov ID: NCT05948735, July 7, 2023.

Exploring Heart Rate Variability Biofeedback as a Nonpharmacological Intervention for Enhancing Perioperative Care: A Narrative Review.

Heart rate variability biofeedback (HRVBF) is a non-invasive therapeutic technique that aims to regulate variability in heart rate. This intervention has promise in mitigating perioperative stress, a critical factor for surgical patient outcomes. This comprehensive review aimed to explore the current evidence on the perioperative role of HRV biofeedback in improving patient outcomes, reducing perioperative stress, enhancing recovery, and optimizing anaesthesia management. A review of the PubMed and Google Scholar databases was conducted to identify articles focused on HRVBF in relation to the perioperative period. Studies were selected using appropriate keywords in English (MeSH). Ample potential applications of HRVBF in clinical anaesthesia have been identified and proven feasible. It is a non-invasive and an easy method an anaesthesiologists has at its disposal with potential utility in reducing perioperative stress, as a tool of optimization of comorbidities, analgesia supplementation and in predicting catastrophic complications. Although HRVBF has the potential to enhance anaesthesia management and improve patient outcomes, several limitations and challenges must be addressed to maximize its clinical utility. Overcoming these obstacles through research and technological advancements will be crucial for realizing the full benefits of HRVBF in perioperative care.

Особенности взаимосвязи регуляции кардиоритма и компонентов внутренней картины болезни у студентов

&lt;p&gt;The work is aimed at identifying the features of the mechanisms of regulation of cardiac rhythm, which determine adaptive behavior in situations of health disorders. Materials from two empirical studies conducted on a sample of 1&lt;sup&gt;st&lt;/sup&gt; to 4&lt;sup&gt;th&lt;/sup&gt; year students at Yelets University are presented. The study 1 (N=160) involved respondents aged 17 to 23 years of both sexes, of whom 37.5% had various health problems. In study 2 (N=60), students (average age 21&amp;plusmn;2.3 years), of which 50% belong to the category of chronically ill, 50% had periodic health problems. Study 2 included five stages, in which four levels of the internal picture of the disease (IPD) were diagnosed and cardiac rhythm measurements were performed at rest and against the background of existing disease memories. The following methods were used: SF-36 Health Status Survey, Health, Activity, and Mood questionnaire, SCL-90-R, &amp;ldquo;Coping behavior in stressful situations&amp;rdquo;, &amp;ldquo;Level of subjective control&amp;rdquo;, TATD method. The fixation of the heart rate variability was carried out using the hardware and software complex OMEGA-M. The results obtained allow us to say that there is a correlation between the individual components of IPD and the parameters of regulation of heart rate variability. The optimal state of the body's homeostatic systems, which ensure successful adaptation, is characterized by the activity of the parasympathetic department of autonomic nervous system in the process of cardioregulation.&lt;/p&gt;

Epigallocatechin gallate enhances sympathetic heart rate variability and decreases blood pressure in obese subjects: a randomized control trial

This study aimed to investigate effects of epigallocatechin gallate (EGCG) on blood pressure (BP) and autonomic nervous system, indicated by 5-min heart rate variability (HRV) measurement in obese subjects, and determine correlations of BP with metabolic factors. In a double-blind, randomized controlled trial, obese subjects (n = 30) were randomly allocated to receive 150 mg EGCG (n = 15) or placebo (n = 15) twice a day without dietary restrictions. After 8-week EGCG treatment, systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) significantly decreased, while the low-frequency (LF) to high-frequency power (HF) ratio (LF/HF ratio) significantly increased (P < 0.05 all), indicating a shift toward sympathetic dominance, either directly or indirectly after BP lowering. SBP had positive correlations with obesity parameters, leptin, insulin, and insulin resistance but had a negative correlation with insulin sensitivity. DBP was positively correlated with age and HF in normalized unit, but negatively correlated with height and LF in ms2. High-density lipoprotein cholesterol (HDL-C) was negatively correlated with SBP, DBP, and MAP reflecting its protective effect against elevated BP. In conclusion, the 8-week EGCG treatment decreased BP and increased the LF/HF ratio, reflecting increased sympathetic activity, either a direct EGCG effect or an indirect compensatory response following BP reduction.

Multi-Sensor Biomarker Using Accelerometer and ECG Data

The development of multi-sensor biomarkers offers a promising avenue for enhancing personalized healthcare and remote monitoring. This study focuses on the integration of accelerometer and electrocardiogram (ECG) data to create a comprehensive multi-sensor biomarker capable of assessing both physical activity and cardiovascular health. Accelerometers track movement patterns, activity levels, and postures, while ECG sensors monitor heart rate, heart rate variability (HRV), and overall cardiac function. By combining these data streams, it is possible to correlate physical exertion with heart performance, resulting in a more holistic health assessment. This research employs advanced machine learning algorithms to analyze synchronized accelerometer and ECG data, identifying patterns that reflect an individual's physiological state. The primary goal is to develop a reliable, real-time biomarker that can detect early signs of disease, monitor chronic conditions, and support preventive health measures. This multi-sensor approach aims to improve accuracy in health assessments by providing deeper insights into the relationship between physical activity and cardiovascular function.

The ability of peripheral neurophysiological biomarkers to predict future psychological conditions among geriatric populations

ObjectiveThough the association between peripheral neurophysiological biomarkers and psychological conditions is widely discussed, there is still limited evidence about the ability of peripheral biomarkers to predict psychological outcomes, especially among geriatric populations. MethodsThe study is designed as a prospective cohort study. We collected information from participants aged over 55 years. The participants were evaluated at the start of the study (T0) and 6–9 months later (T1). Information about demographic profiles, peripheral neurophysiological biomarker recordings (including heart rate variability, finger temperature, skin conductance, and electromyogram), and psychological measurements (including Brief Symptom Rating Scale-5, Chinese Happiness Inventory, and Short Portable Mental Status Questionnaire) were collected at T0. At T1, participants reported self-rated questionnaires for psychological outcomes (Patient Health Questionnaire-15, health anxiety questionnaire, Beck Depression Inventory-II, and Beck Anxiety Inventory) and were evaluated with Mini-Mental State Examination by the staff. The association between the peripheral biomarkers and psychological outcomes was evaluated via multiple regression models. ResultsA total of 385 participants were included in the study and the average age was 74.49 ± 7.34 years. Both stepwise multiple linear and logistic models showed a significant association between decreased skin conductance and increased/presence of depression at T1. The receiver operating characteristic (ROC) curve analysis of skin conductance for depression was fair (area under curve = 0.812). ConclusionsThe ability of skin conductance to predict depression among geriatric populations may facilitate the detection of geriatric depression and future research on the pathophysiology.

Anthropometric Predictors of Heart Rate Variability in Overweight Individuals: A Comparative Study.

Introduction The autonomic nervous system is crucial in regulating cardiovascular function. Heart rate variability (HRV) analysis, a non-invasive method to assess autonomic function, reflects the beat-to-beat variations in heart rate and provides insights into the dynamic interplay between sympathetic and parasympathetic influences on the cardiovascular system. In this study, we aimed to find the HRV parameters in overweight individuals by comparing different anthropometric parameters, including body mass index (BMI), percentage body fat (%BF), waist circumference (WC), and waist-hip ratio (WHR). Method The descriptive cross-sectional study was conducted on 132 healthy first-year MBBS students (82 males and 50 females), aged between 17 and 23 years. Anthropometric parameters (BMI, %BF, WC, WHR) and HRV were recorded for the participants. The HRV parameters were analyzed for either gender. A student 't' test was used to test the difference between groups BMI <25 kg/m2 and = or >25 kg/m2,and a p-value less than 0.05 was taken to be statistically significant. The Pearson correlation coefficient was used to show the relationship between HRV parameters and BMI, %BF, WC, and WHR as the independent variables. Result A total of 132healthy individuals participated in the study, including 82 males and 50 females. The participants had a mean age of 18.72 ± 0.98 years. Our results suggest that while WC and WHR can be used alongside BMI to indicate sympathetic hyperactivity in males, BMI remains the most significant predictor in females. We found gender-specific differences in high-frequency (HF) related to various anthropometric measures, but these differences were not statistically significant. The low-frequency:high-frequency (LF/HF) ratio exhibits strong positive correlations with all measured anthropometric parameters, suggesting that increased values in BMI, %BF, WC, and WHR are associated with greater sympathetic involvement. Conclusion WC and WHR, alongside BMI, are reliable indicators of heightened sympathetic activity in both males and females. These measures should be utilized to assess healthy individuals for the early diagnosis of dysautonomia, disrupt the cycle of sympathetic overactivity, and prevent cardiovascular complications. All these anthropometric parameters are valuable for indicating sympathovagal balance, making them essential tools in the proactive management of autonomic dysfunction and associated health risks.

Alleviation of physiological stress response by apple aroma

ABSTRACT Objective The study evaluated the potential of apple aroma to alleviate physiological stress response induced by a short-term cognitive stressor. It investigated the effects of apple aroma on cardiac and peripheral autonomic nervous system activity under stressful conditions. Methods Within-subject experiments were conducted with 25 healthy male university students with a 30-minute calculation task under three conditions: Apple, Chamomile (CHA), and Di propylene glycol (DPG) (scentless air). The aroma administration was precisely controlled and counterbalanced. Cardiac activity on electrocardiograms and nose tip temperature were recorded throughout the experiment. A visual analog scale and a scent questionnaire were subjective measures. Results Apple aroma demonstrated a significantly smaller increase in heart rate (t [24] = 3.36, p = 0.008 vs. DPG, t [24] = 4.06, p = 0.001 vs. CHA), and a decrease in the high-frequency component of heart rate variability (t [24] = 2.81, p = 0.029 vs. DPG, t [24] = 3.48, p = 0.006 vs. CHA) compared to the other conditions, representing a smaller enhancement of cardiac sympathetic nervous system activity and smaller suppression of cardiac parasympathetic nervous system activity respectively. Conclusion Apple aroma showed efficacy in alleviating the physiological stress response in terms of cardiac activity. Apple was also considered significantly preferable and comfortable compared to the other conditions, which would be beneficial in the context of aromatherapy.

Heart rate variability in horses with and without severe equine asthma.

Equine asthma in severe form (severe equine asthma [sEA]) shares remarkable similarities with human asthma. Human studies detected changes in the autonomic nervous system function in asthmatic patients based on heart rate variability (HRV) analysis. Observational study. To investigate the relationship between sEA and HRV in horses. Twenty horses diagnosed with sEA and 20 asymptomatic (non-sEA) horses were investigated. SEA horses showed clinical signs. The RR intervals of the ECG were recorded for 1 h at rest between 9 AM and 11 AM using a heart rate (HR) monitor. HRV data were calculated using Kubios software. Parameters recorded for the sEA and non-sEA groups were compared using one-way MANOVA model. The significance level was set at α = 0.05. SD2 (mean 99.6 ± SD 25.3 vs. 42.5 ± 17.1), SDNN (82.7 ± 20.7 vs. 41.3 ± 14.3), TINN (398.1 ± 104.9 vs. 209.3 ± 71.9), SD2/SD1 ratio (1.7 ± 0.2 vs. 1.1 ± 0.3), Total power (4740.2 ± 1977.9 vs. 1503.0 ± 1179.3), LF (2415.3 ± 1072.4 vs. 707.4 ± 649.9), SD1 (60.9 ± 15.9 vs. 39.2 ± 14.1), RMSSD (86.0 ± 22.6 vs. 55.3 ± 19.8) and HF (1575.8 ± 902.5 vs. 578.1 ± 491.1) were lower in sEA horses compared with the non-sEA horses (p < 0.01 for each variable). SD2, SDNN, TNN, the SD2/SD1 ratio and Total power showed the greatest discriminatory power in differentiating the sEA and non-sEA groups. Small sample size. Our findings indicate that like humans, asthmatic horses show an overall reduction in autonomic control. A relative increase of the parasympathetic modulation of the heart was also observed. After further investigations, HRV measurement might be a non-invasive approach to monitor autonomic nervous system responses of sEA horses.

PSXIII-13 Evaluation of physiological functions and performance in laying hens in different housing systems

Abstract Egg production faces many challenges of economics, disease control and animal welfare concerns. Therefore, investigation of physiological characteristics in laying hens should be required for further discussion on such issues from a scientific point of view. In this study, we evaluated physiological functions and production parameters of hens raised in three different housing systems, conventional battery cage (CC), enriched cage (EC) and aviary system (AV). Lohmann Selected Leghorn Lite laying hens (n = 251) were used. At first, all the pullets were housed in CC. Then, a telemetric transmitter was implanted to randomly selected 18 hens on d 171 after birth to record electrocardiograms (ECGs), heart rate (HR), body temperature (BT) and locomotor activity (LA). Heart rate variability (HRV), which was analyzed using ECG, has been established as a suitable method for investigating autonomic nervous functions, and to assess stress and well-being of housing systems. On d 200 after birth, some of the hens were randomly selected and transferred to EC or AV (CC; n = 88, EC; n = 72, AV; n = 91), including hens implanted a transmitter (6 hens in each group). All parameters at 10 d before and 1 wk after the group division were compared. Egg laying rate (ELR), feed conversion ratio (FCR) and shell deformation were evaluated for egg production parameters. Hens were basically housed under the same management condition, and a constant light-dark cycle (light-on from 0300 to 1930 h). Feeding was conducted during light-phase, and water was supplied ad libitum. Statistical significance was defined as P &amp;lt; 0.05. Comparing the physiological parameter, HR during dark-phase and LA during light-phase after transferred to EC or AV were greater than those in CC. However, there was no significant difference in HR during light-phase or LA during dark-phase between CC and the other two groups. The high frequency (HF) power of HRV, which reflects parasympathetic nervous function, was high during the dark-phase (7.59 ± 1.56) and low during the light-phase (6.04 ± 0.78) in CC. This diurnal variation disappeared in EC or AV because the HF power during the dark-phase decreased. As for production, ELR, FCR and shell deformation were decreased after moved to AV, which were not found in other two groups after the group division. This study was conducted to clarify the effects of housing systems on the physiological functions and productivity of laying hens, and these results suggest that CC might provide hens with parasympathetic dominance with greater quality of rest in dark-phase, and AV causes the reduction of egg production. However, we cannot completely rule out the possibility that these results are influenced by movement to a different housing system. Therefore, further analysis should be performed to assess the relations between physiological functions, management and egg production.