Heart rate variability is related to self-reported physical activity in a healthy adolescent population

Preterm birth risk stratification through longitudinal heart rate and HRV monitoring in daily life

Preterm birth (PTB) remains a global health concern, impacting neonatal mortality and lifelong health consequences. Traditional methods for estimating PTB rely on electronic health records or biomedical signals, limited to short-term assessments in clinical settings. Recent studies have leveraged wearable technologies for in-home maternal health monitoring, offering continuous assessment of maternal autonomic nervous system (ANS) activity and facilitating the exploration of PTB risk. In this paper, we conduct a longitudinal study to assess the risk of PTB by examining maternal ANS activity through heart rate (HR) and heart rate variability (HRV). To achieve this, we collect long-term raw photoplethysmogram (PPG) signals from 58 pregnant women (including seven preterm cases) from gestational weeks 12-15 to three months post-delivery using smartwatches in daily life settings. We employ a PPG processing pipeline to accurately extract HR and HRV, and an autoencoder machine learning model with SHAP analysis to generate explainable abnormality scores indicative of PTB risk. Our results reveal distinctive patterns in PTB abnormality scores during the second pregnancy trimester, indicating the potential for early PTB risk estimation. Moreover, we find that HR, average of interbeat intervals (AVNN), SD1SD2 ratio, and standard deviation of interbeat intervals (SDNN) emerge as significant PTB indicators.

Cardiorespiratory fitness, perceived fitness and autonomic function in in-patients with different depression severity compared with healthy controls

Over 300 million individuals worldwide suffer from major depressive disorder (MDD). Individuals with MDD are less physically active than healthy people which results in lower cardiorespiratory fitness (CRF) and less favorable perceived fitness compared with healthy controls. Additionally, individuals with MDD may show autonomic system dysfunction. The purpose of the present study was to evaluate the CRF, perceived fitness and autonomic function in in-patients with MDD of different severity compared with healthy controls. We used data from 212 in-patients (age: 40.7 ± 12.6 y, 53% female) with MDD and from 141 healthy controls (age: 36.7 ± 12.7 y, 58% female). We assessed CRF with the Åstrand-Rhyming test, self-reported perceived fitness and autonomic function by heart rate variability (HRV). In specific, we used resting heart rate, time- and frequency-based parameters for HRV. In-patients completed the Beck Depression Inventory-II (BDI-II) to self-assess the subjectively rated severity of depression. Based on these scores, participants were grouped into mild, moderate and severe MDD. The main finding was an inverse association between depression severity and CRF as well as perceived fitness compared with healthy controls. Resting heart rate was elevated with increasing depression severity. The time-based but not the frequency-based autonomic function parameters showed an inverse association with depression severity. The pattern of results suggests that among in-patients with major depressive disorder, those with particularly high self-assessed severity scores show a lower CRF, less favorable perceived fitness and partial autonomic dysfunction compared to healthy controls. To counteract these conditions, physical activity interventions may be effective.

Using explainable machine learning and fitbit data to investigate predictors of adolescent obesity

Sociodemographic and lifestyle factors (sleep, physical activity, and sedentary behavior) may predict obesity risk in early adolescence; a critical period during the life course. Analyzing data from 2971 participants (M = 11.94, SD = 0.64 years) wearing Fitbit Charge HR 2 devices in the Adolescent Brain Cognitive Development (ABCD) Study, glass box machine learning models identified obesity predictors from Fitbit-derived measures of sleep, cardiovascular fitness, and sociodemographic status. Key predictors of obesity include identifying as Non-White race, low household income, later bedtime, short sleep duration, variable sleep timing, low daily step counts, and high heart rates (AUCMean = 0.726). Findings highlight the importance of inadequate sleep, physical inactivity, and socioeconomic disparities, for obesity risk. Results also show the clinical applicability of wearables for continuous monitoring of sleep and cardiovascular fitness in adolescents. Identifying the tipping points in the predictors of obesity risk can inform interventions and treatment strategies to reduce obesity rates in adolescents.

Heart rate variability is reduced in COVID-19 survivors and associated with physical activity and fatigue

Reduced heart rate variability (HRV) and fatigue are common after COVID-19 infection and both are potentially influenced by physical activity (PA). We compared resting HRV, PA from accelerometers and questionnaires, and self-reported fatigue in 41 COVID-19 survivors (~8 months postinfection, 38 ± 17 years) with 41 matched controls. Differences in HRV were observed on acceleration capacity (p = 0.041), deceleration capacity (p = 0.032), high-frequency peak frequency (p = 0.019), absolute low-frequency power (p = 0.042), relative very low-frequency power (p = 0.012), SD2 (from Poincare plot; p = 0.047), and DFA2 (slope of long-term detrended fluctuation analysis; p = 0.004). Fatigue was greater in COVID-19 survivors (p < 0.001) with no differences in PA. Moderate-vigorous physical activity (MVPA) (Standardized Beta = -0.427, p = 0.003) and steps per day (Standardized Beta = -0.402, p = 0.007) were associated with DFA2 in COVID-19 survivors after controlling for age, sex, and body fat percentage. Fatigue was correlated to less MVPA (Spearman's rho = 0.342, p = 0.031) and fewer steps per day (rho = 0.329, p = 0.038) in COVID-19 survivors, and was indirectly linked to HRV through these PA mediators (Estimate = -0.20; p = 0.040). We present a model showing the complex relations between HRV, PA, and fatigue that provides the foundation for strategies to improve outcomes and rehabilitation after COVID-19 infection.

Association between Sleep Quality and Cardiac Autonomic Modulation in Adolescents: A Cross Sectional Study

Objective  To analyze the impact of sleep quality/duration on cardiac autonomic modulation on physically active adolescents with obesity. Materials and Methods  The present cross-sectional study included 1,150 boys with a mean age of 16.6 ± 1.2 years. The assessment of cardiac functions included the frequency domain of heart rate variability (HRV; low frequency - LF; high frequency - HF; and the ratio between these bands -LF/HF -, defined as the sympathovagal balance), and each parameter was categorized as low / high . Physical activity levels and sleep quality/duration were obtained by questionnaires. Abdominal obesity was assessed and defined as waist circumference > 80 th percentile. Results  Poor sleep quality resulted in lower HF (odds ratio [OR]: 1.8; 95% confidence interval [95%CI]: 1.01-3.21]) regardless of physical activity and abdominal obesity. Moreover, the study found no association between sleep duration and HRV parameters in adolescents. Conclusion  Sleep quality, not sleep duration, reduces parasympathetic cardiac modulation apart from other factors such as physical activity and abdominal obesity in adolescents.

Heart Rate Variability as a Reliable Biomarker Following Concussion: A Critically Appraised Topic

CLINICAL SCENARIO

Recent systematic reviews show conflicting information regarding the effect of concussion on cardiac autonomic function. Controlled aerobic exercise is the most popular intervention for those recovering from a concussion. There is a gap in the literature supporting the utility of objective metrics during exertional return to play protocols and rehabilitation.

CLINICAL QUESTION

Can heart rate variability (HRV) during physical exertion be a reliable biomarker over time for those who suffered a sport-related concussion?

SUMMARY OF KEY FINDINGS

A literature search produced 3 studies relevant to the clinical question. One, a prospective-matched control group cohort study, reported disturbances in HRV during physical exertion in those with a history of concussion, and identified persistent HRV dysfunction after resolution of subjective complaints, return to play, and with multiple concussive events. Second, a cross-sectional cohort study found an HRV difference in those with and without a history of concussion and in HRV related to age and sex. Finally, the prospective longitudinal case-control cohort study did not find sex or age differences in HRV and concluded that, although postconcussion HRV improved as time passed, resting HRV was not as clinically meaningful as HRV during exertional activities.

CLINICAL BOTTOM LINE

There is emerging evidence to support the use of HRV as an observable biomarker, over time, of autonomic function during physical exertion following a sport-related concussion. However, the meaningfulness of HRV data is not fully understood and the utility seems individualized to the level of athlete, age, and sex and, therefore, cannot be generalizable. In order to be more clinically meaningful and to assist with current clinical decision making regarding RTP, a preinjury baseline assessment would be beneficial as an individualized reference for baseline comparison.

STRENGTH OF RECOMMENDATION

Although HRV is not fully understood, currently, there is grade B evidence to support the use of individualized baseline exertional HRV data as comparative objective metric to assess the autonomic nervous system function, over time, following a concussive event.

Effects of physical activity on heart rate variability in children and adolescents: a systematic review and meta-analysis

The aim of the study was to investigate the effects of physical activity (PA) on heart rate variability (HRV) in children and adolescents. We conducted a research of Web of Science, PubMed, ScienceDirect, Springer-Link and EBSCO-host. The revised Newcastle-Ottawa Scale was used in an investigative analysis to assess bias risk. A total of 21 studies were included. Overall, medium-sized associations were found between PA and low frequency and high frequency in children and adolescents. High PA level had significantly higher standard deviation of RR intervals and root of the mean of the sum of the squares of differences between adjacent RR intervals in children and adolescents. The effects of PA on HRV were consistent in children and adolescents. Our systematic review and meta-analysis revealed medium-sized between PA and HRV in children and adolescents. Promoting children's and adolescents' participation in moderate-to-vigorous physical activity (MVPA) will increase parasympathetic nerve activity and decreased sympathetic nerve activity. Our findings support motivating children and adolescents to engage in more MVPA in their daily lives to improve autonomic nervous system function and promote cardiovascular safety.

Relationship between vigorous physical activity and health care costs among adolescents: ABCD Growth Study

Background

The relationship between physical activity and health care costs among adolescents is not yet clear in the literature.

Objective

To analyze the relationship between physical activity and annual health care costs among adolescents.

Methods

The present sample was composed of 85 adolescents of both sexes with ages ranging from 11 to 18 years (mean age 15.6 ± 2.1). Health care costs were self-reported every month for 12 months, and information on health care values was verified with local pharmacies, private health care plans, and the National Health Service. The time spent in different physical activity intensities was objectively measured by accelerometers. Confounding variables were: sex, age, somatic maturation, body fatness, blood pressure, and components of dyslipidemia and insulin resistance. Multivariate models were generated using generalized linear models with gamma distribution and a log-link function.

Results

The overall annual health care cost was US$ 733.60/ R$ 2,342.38 (medication: US$ 400.46 / R$ 1,278.66; primary and secondary care: US$ 333.14 / R$ 1,063.70). The time spent in vigorous physical activity (minutes/day) was negatively related to health care costs (r = -0.342 [95% CI: -0.537,—0.139]; β = -0.06 cents (95% CI: -0.089, -0.031).

Conclusion

Vigorous physical activity seems to be associated with lower health care costs among adolescents.

Daily physical activity, cardiorespiratory fitness, nutritional status, endothelial function, and autonomic modulation in school-age adolescents: A principal component analysis

PURPOSE

This study evaluated the association between cardiorespiratory fitness, abdominal obesity, blood pressure, endothelial function, and autonomic modulation in school-age adolescents exhibiting different levels of habitual physical activity and nutritional status, through a multivariate statistical approach.

METHODS

101 adolescents aged 15-18 years (54 females) underwent assessments of daily physical activity, body mass index, cardiorespiratory fitness, reactive hyperemia, and heart rate variability. Based on BMI adjusted for age and sex (z-BMI), 21 adolescents were classified as 'overweight' (9 girls), and 9 as 'obese' (4 girls). The common variation between those variables was assessed through Principal Component Analysis (PCA).

RESULTS

Main axis of common variation of outcomes analyzed defined four principal components (PCs) accounting for 69.7% of overall variance, related to 'abdominal obesity and blood pressure' (PC1; eigenvalue=2.76), 'cardiorespiratory fitness, endothelial function, and autonomic modulation' (PC2, eigenvalue=1.98), 'cardiorespiratory fitness' (PC3, eigenvalue=1.21), and 'sedentary behavior' (PC4, eigenvalue=1.02). Girls reported longer screen time and sedentary behavior than boys. Notwithstanding, in both sexes poorer cardiorespiratory fitness corresponded to lower reactive hyperemia and vagal modulation, irrespective of the nutritional status. Overall, adolescents classified as 'obese' and 'sedentary' exhibited poorer CRF concomitantly to autonomic and endothelial dysfunctions.

CONCLUSION

In school-age adolescents, endothelial and autonomic dysfunctions related to poor cardiorespiratory fitness, irrespective of the nutritional status and physical activity level. However, endothelial and autonomic dysfunctions were more prevalent among adolescents combining poor cardiorespiratory fitness, reduced levels of daily physical activity, and overweight/obesity.

Performing more than 20 purposeful gameplay headers in a soccer season may alter autonomic function in female youth soccer players

This study evaluated the effects of cumulative purposeful soccer heading on autonomic nervous system function in 22 female youth soccer players (13.3 ± 0.9 years). A 10 minute electrocardiogram recording was collected at baseline and following the 20 game season (post-season) to calculate measures of heart rate variability (HRV), including standard deviation of the normal-normal intervals, total power, high frequency (HF), low frequency (LF), LF:HF, normalized HF and normalized LF. Participants were categorized into low- (<20 headers per season; n = 13) and high- (>20 headers per season; n = 9) exposure groups. Mann-Whitney U tests demonstrated no significant differences between groups for any HRV metric. However, the increased normalized LF power (low exposure 8.67 and high exposure -31.17, respectively; r = 0.35) and LF:HF power (-6.39 and 15.80, respectively; r = 0.35), between groups had moderate practical significance. Therefore, female youth players who perform more than 20 purposeful headers during a soccer season may exhibit altered autonomic function.

Autonomic Profile, Physical Activity, Body Mass Index and Academic Performance of School Students

The aim of this study was to analyze the autonomic modulation, physical activity, body mass index, and academic performance of preschool and school students by grade. Extracurricular physical activity, heart rate variability, body mass index, and objective and subjective academic performance were analyzed in 180 preschool and primary school students (7.91 ± 2.29 years). Significant lower heart rate and higher parasympathetic modulation were found in 10–12-year-old primary education students. The 8–9-year-old students obtained the worst results in English and in five of the subjective academic performance items. Students aged 10–12 years old presented the highest body composition values. No significant differences were found on the extracurricular physical activity by age. No correlation between autonomic profile, physical activity, and body composition with objective academic performance was found. Nerveless subjective academic performance perception of teachers presented a negative correlation with body composition and the parasympathetic modulation. School students presented an increased body mass index and parasympathetic modulation by age. Physical activity of all students, independently of the age, were lower than the official recommendations.

Changes in Continuous, Long-Term Heart Rate Variability and Individualized Physiological Responses to Wellness and Vacation Interventions Using a Wearable Sensor

There are many approaches to maintaining wellness, including taking a simple vacation to attending highly structured wellness retreats, which typically regulate the attendee's personal time and activities. In a healthy English-speaking cohort of 112 women and men (aged 30–80 years), this study examined the effects of participating in either a 6-days intensive wellness retreat based on Ayurvedic medicine principles or unstructured 6-days vacation at the same wellness center setting. Heart rate variability (HRV) was monitored continuously using a wearable ECG sensor patch for up to 7 days prior to, during, and 1-month following participation in the interventions. Additionally, salivary cortisol levels were assessed for all participants at multiple times during the day. Continual HRV monitoring data in the real-world setting was seen to be associated with demographic [HRV_ALF: β_Age = 0.98 (95% CI = 0.96–0.98), false discovery rate (FDR) < 0.001] and physiological characteristics [HRV_PLF: β = 0.98 (95% CI = 0.98–1), FDR =0.005] of participants. HRV features were also able to quantify known diurnal variations [HRV_LF/HF: β_{ACT:night vs. early−morning} = 2.69 (SE = 1.26), FDR < 0.001] along with notable inter- and intraperson heterogeneity in response to intervention. A statistically significant increase in HRV_ALF [β = 1.48 (SE = 1.1), FDR < 0.001] was observed for all participants during the resort visit. Personalized HRV analysis at an individual level showed a distinct individualized response to intervention, further supporting the utility of using continuous real-world tracking of HRV at an individual level to objectively measure responses to potentially stressful or relaxing settings.

Physical activity is associated with cardiac autonomic function in adolescent men

Introduction

Moderate to vigorous physical activity (MVPA) has been shown to be associated with autonomic regulation of the heart measured with heart rate variability (HRV). Only a limited amount of studies have examined this relationship among adolescents, and the effects of increasing PA on HRV is not well established. The aim of this study was to investigate how overall self-reported PA associates with HRV in a large population of adolescent men.

Methods

The study was part of the Finnish MOPO study consisting of 3629 young men (mean age 18, SD 1 years) enrolled for military call-ups in 2009–2013. Overall PA, including both the intensity and frequency of habitual exercise, was assessed by a questionnaire and the respondents categorized into four groups of PA (low, moderate, high and top). Short-term HRV, physical performance and body composition were measured.

Results

HRV, as indicated by mean ln rMSSD, increased according the PA categories as follows: low (3.65 ms (SD 0.7), p<0.001 vs. other groups), moderate (3.78 ms (0.6) p<0.001), high (3.85 ms (0.6) p<0.001) and top activity (3.93 ms (0.6) p<0.001) According to the multivariable linear regression analysis, a significant positive relationship (β = 0.129, p<0.05) was observed between self-reported PA and ln rMSSD independent of body mass index, waist circumference and fat percentage.

Conclusions

Physical activity was positively associated with cardiac autonomic regulation, in adolescent men. A linear increase in HRV according to PA was observed, suggesting that even slight increments in PA might be beneficial for cardiac autonomic regulation The results emphasize the importance of physical activity in improving cardiac health in young people.

Autonomic responses induced by aerobic submaximal exercise in obese and overweight adolescents

BACKGROUND

Graded exercises tests are performed in adult populations; nonetheless, the use of this type of assessment is greatly understudied in overweight and obese adolescents.

OBJECTIVE

To investigate heart rate autonomic responses to submaximal aerobic exercise in obese and overweight adolescents.

METHODS

We recruited 40 adolescents divided into two groups: (1) overweight group comprising 10 boys and 10 girls between Z-score +1 and +2 and (2) obese group comprising 10 boys and 10 girls above Z-score &gt;+2. Heart rate variability was analysed before (T1) and after exercise (T2-T4) on treadmill at a slope of 0%, with 70% of the maximal estimated heart rate (220 - age) for 20 minutes.

RESULTS

Heart rate in the overweight group was: 93.2±10.52 bpm versus 120.8±13.49 bpm versus 94.6±11.65 bpm versus 93.0±9.23 bpm, and in the obese group was: 92.0±15.41 bpm versus 117.6±16.31 bpm versus 92.1±12.9 bpm versus 91.8±14.33 bpm. High frequency in the overweight group was: 640±633.1 ms2 versus 84±174.66 ms2 versus 603.5±655.31 ms2 versus 762.6±807.21 ms2, and in the obese group was: 628.4±779.81 ms2 versus 65.4±119.34 ms2 versus 506.2±482.70 ms2 versus 677.9±939.05 ms2; and root mean square of successive differences in the overweight group was: 37.9±18.81 ms versus 10.9±8.41 ms versus 32.8±24.07 ms versus 36.7±21.86 ms, and in the obese group was: 38.7±23.17 ms versus 11.5±8.62 ms versus 32.3±16.74 ms versus 37.3±24.21 ms. These values significantly changed during exercise compared with resting values in overweight and obese groups. Moreover, we also reported no significant difference of resting parasympathetic control of heart rate between obese and overweight adolescents.

CONCLUSION

There was no significant difference of autonomic responses elicited by submaximal aerobic exercise between overweight and obese adolescents.

Effect of gender-related depression on heart rate variability during an autonomic nervous test

Patients with depression have lower heart rate variability (HRV) compared with controls. However, studies have indicated HRV difference between male and female controls. The gender effect might be interactive with the depression effect on the HRV, resulting in a low accuracy of recognising the patients with depression from the controls. Our study explores the effect of gender-related depression on HRV. Four ANS tests including resting, deep breathing, Valsalva, and orthostatic test are employed as stimuli. HRV were collected from 182 subjects comprising 91 depressive patients (33 females/58 males) and 91 controls (33 females/58 males) in the four tests. Time and frequency domains and nonlinear parameters are employed to quantify HRV. Two-way ANOVA is applied to evaluate the effect of gender-related depression. Most HRV parameters of the patients significantly differ from those of the controls, but some parameters indicate different depression effect between the males and females in the deep breathing and Valsalva test. Some HRV parameters illustrate significant difference between the male and female controls. Therefore, the effect of depression on HRV of each gender should be investigated.

Association between dysfunction of autonomic nervous system activity and mortality in schizophrenia

BACKGROUND

Patients with schizophrenia have a higher mortality risk than the general population. Additionally, the autonomic nervous system (ANS) activity of patients with schizophrenia is lower and more dysfunctional than that of the general population. Nonetheless, the association between ANS dysfunction and mortality in schizophrenia is unclear. The aim of this study was to investigate the association between ANS activity and mortality in schizophrenia and to evaluate the predictive values of heart rate variability for long-term survival.

METHODS

This study involves the 10-year follow-up of a sample population consisting of 59 Japanese inpatients with schizophrenia between 60 and 70 years of age from 2007 to 2016. The ANS activity of all patients was evaluated using heart rate variability in 2007.

RESULTS

Fifty-three participants could be followed up because they stayed in the hospital during the follow-up period. Of these patients, 11 died during follow-up. Their mean age at death was 70.55 ± 3.45 years. The parasympathetic activity of nonsurvivors was significantly lower than that of survivors, and multiple logistic regression analysis showed a significant association between death and parasympathetic activity.

CONCLUSION

We suggest that decreased parasympathetic activity could be associated with 10-year all-cause mortality in older schizophrenic patients.

Aberrant parasympathetic reactivity to acute psychosocial stress in male patients with schizophrenia spectrum disorders

Autonomic dysfunction represents a core domain of the pathophysiology of schizophrenia spectrum disorders (SCZ), with aberrant physiologic arousal underlying maladaptive social and cognitive behaviors. Antagonistic parasympathetic and sympathetic systems support autonomic flexibility to appropriately regulate arousal and respond to environmental challenges, which can be modeled using physiologic measures. SCZ patients consistently show heightened basal stress, however, their parasympathetic reactivity to an acute psychosocial stressor is poorly understood. Heart period (HP-arousal), respiratory sinus arrhythmia (RSA-parasympathetic vagal activity), and their relationship were measured in SCZ patients (n = 19) and healthy controls (n = 20) at baseline and during psychosocial stress exposure. Parasympathetic vagal control of arousal, reflected in RSA-HP coupling, was assessed for the first time in SCZ. Patients demonstrated blunted physiologic reactivity (less change in heart period and respiratory sinus arrhythmia), a unique increase in respiratory sinus arrhythmia relative to baseline during recovery, and elevated arousal was associated with poor cognitive performance and greater positive symptoms. Arousal regulation was tightly controlled by parasympathetic activity in controls only, indicated by a strong association between changes in heart period and respiratory sinus arrhythmia. Results are the first to demonstrate maladaptive, inefficient parasympathetic arousal regulation (RSA-HP decoupling) in reaction to psychosocial stress in SCZ, representing an autonomic profile incompatible with appropriate social and emotional functioning.

Physical Activity and Heart Rate Variability in Adolescents with Abdominal Obesity

Physical activity is a protective factor for autonomic dysfunction. However, whether this occurs in adolescents with abdominal obesity is still unclear. Thus, the aim of this study was to analyze the association between physical activity and heart rate variability (HRV) in adolescents with and without abdominal obesity. This cross-sectional study included 1152 boys (age: 17 ± 1 years). HRV measures of time (root mean square of the squared differences between adjacent normal RR intervals-RMSSD and the percentage of adjacent intervals over 50 ms-PNN50) and frequency domains (balance sympathetic-vagal-LF/HF) were evaluated, as well as total physical activity, commuting physical activity, leisure-time physical activity, and abdominal obesity. All physical activity domains were associated with better RMSSD, PNN50, and LF/HF in normal weight adolescents (p < 0.05), whereas in adolescents with abdominal obesity only leisure-time physical activity was associated with better PNN50 (b = 0.174, p = 0.035) independent of age, period of the day, body mass index, and blood pressure. In conclusion, higher leisure-time physical activity, but not total and commuting physical activity levels, was associated with improved HRV in adolescents with abdominal obesity.

Sex- and Age-Dependent Differences in Autonomic Nervous System Functioning in Adolescents

PURPOSE

We assessed sex- and age-dependent differences in a cross-sectional analysis of cardiac autonomic nervous system (ANS) regulation during sleep in adolescents.

METHODS

Nocturnal heart rate (HR) and heart rate variability (HRV) metrics, reflecting ANS functioning, were analyzed across the night and within undisturbed rapid eye movement (REM) and non-REM sleep in 149 healthy adolescents (12-22 years; 67 female) from the National Consortium on Alcohol and Neurodevelopment in Adolescence.

RESULTS

Nocturnal HR was slower in older, more pubertally advanced boys than in younger boys. In girls, HR did not vary according to age or maturity, although overall HRV and vagal modulation declined with age. Although younger boys and girls had similar HR, the male-female HR difference increased by ~2.4 bpm every year (p < .01, higher in older girls). Boys and girls showed expected increases in total HRV across the night but this within-night "recovery" was blunted in girls compared with boys (p < .05). Also, the non-REM and REM difference in HR was greater in girls (p < .01). Models exploring a role of covariates (sleep, mood, reproductive hormones, activity) in influencing HR and HRV showed few significant effects, apart from sedentary activity (higher in older girls), which partially mediated the sex × age interaction in HR.

CONCLUSIONS

Sex-related differences in cardiac ANS function emerge during adolescence. The extent to which sex-age divergences in ANS function are adaptive or reflect underlying sex-specific vulnerability for the development of psychopathology and other health conditions in adolescence needs to be determined.

Heart Rate Variability in Healthy Non-Concussed Youth Athletes: Exploring the Effect of Age, Sex, and Concussion-Like Symptoms

BACKGROUND

Heart rate variability (HRV) is a non-invasive neurophysiological measure of autonomic nervous system regulation emerging in concussion research. To date, most concussion studies have focused on the university-aged athlete with no research examining healthy active youths. Corroborating changes in HRV alongside traditional subjective self-report measures (concussion symptoms) in the non-concussed state provides a foundation for interpreting change following concussion. The objectives were to (1) explore the influence of age and sex on HRV and (2) examine the relationship between HRV and baseline/pre-injury concussion symptom domains (physical, cognitive, emotional, and fatigue) in healthy youth athletes.

METHOD

Healthy, youth athletes 13-18 years of age [N = 294, female = 166 (56.5%), male = 128 (43.5%)] participated in this cross-sectional study. Age, sex, and concussion-like symptoms were collected as part of a baseline/pre-injury assessment. The Post-Concussion Symptom Inventory-SR13 (PCSI-SR13) was used to collect domain scores for physical, cognitive, emotional, and fatigue symptoms. HRV was collected for 24 h. HRV measures included time (SDNN, RMSSD, and pNN50) and frequency (HF, HFnu, LF, LFnu, and total power) domain HRV measures. Variables were logarithmically transformed to increase robustness of linear regression models.

RESULTS

Older youth participants displayed significantly higher HRV compared to younger participants (p < 0.05). Females displayed significantly lower HRV compared to males (p < 0.05). A significant interaction effect between concussion-like symptoms and HRV indicated differential patterns as a function of sex (p < 0.05). Youth athletes who reported more cognitive symptoms had lower HRV (p < 0.05).

CONCLUSION

HRV was found to have a significant relationship with a traditional clinical measure (subjective self-report of concussion-like symptoms) utilized in concussion assessment and management. Baseline/pre-concussion trends in HRV were significantly associated with age and sex, highlighting the value in understanding key demographic factors within the context of concussion-like symptoms.

Is cardiac autonomic function associated with cardiorespiratory fitness and physical activity in children and adolescents? A systematic review of cross-sectional studies

BACKGROUND

Heart rate variability (HRV) is considered to explain improvements in cardiovascular health accrued by physical activity (PA) and cardiorespiratory fitness (CRF) over and above traditional cardiovascular risk factors.

OBJECTIVE

To systematically address associations between HRV, PA and CRF in children and adolescents.

DATA SOURCES

Medline, EMBASE, SportDISCUS and CINAHL Plus were searched on 5th September 2015 and updated on 4th August 2016.

ELIGIBILITY CRITERIA

Observational studies comparing HRV in different groups of PA and CRF, and/or studies investigating associations between PA, CRF and HRV. Sports practices and PA intensities were also included. The square root of the mean of the sum of the squares of differences between adjacent RR intervals (RMSSD), the spectral density in the high (HF) and low (LF) frequency, and the LF/HF ratio were included. Risk of bias was assessed using the adapted Newcastle-Ottawa Scale (NOS).

RESULTS

Heterogeneity exists in the assessment of the exposures and outcomes, and sample characteristics. Risk of bias (NOS) was observed in most of the studies. Studies with low risk of bias showed positive associations between moderate-to-vigorous PA and RMSSD. The evidence for the associations between PA and frequency indices is weak. Similarly, the evidence for the association between CRF and HRV is weak.

CONCLUSIONS

Despite the heterogeneity in the studies, moderate-to-vigorous PA is positively associated with RMSSD, but less clear are the associations between CRF and HRV, as well as other PA intensities. Further research is needed to clarify the role of PA and CRF on HRV in children and adolescents.

Correlation between health-related quality of life in the physical domain and heart rate variability in asymptomatic adults

Background

Reduced health-related quality of life in the physical domain (HRQOL_physical) has been reported to increase risks for cardiovascular disease (CVD); however, the mechanism underlying this phenomenon is still unclear. The autonomic nervous system (ANS) that connects the body and mind is a biologically plausible candidate to investigate this mechanism. The aim of our study is to examine whether the HRQOL_physical independently contributes to heart rate variability (HRV), which reflects ANS activity.

Methods

We recruited 329 physically and mentally healthy adults. All participants completed Beck Anxiety Inventory, Beck Depression Inventory and World Health Organization Questionnaire on Quality of Life: Short Form-Taiwanese version (WHOQOL-BREF). They were divided into groups of individuals having high or low scores of HRQOL_physical as discriminated by the quartile value of WHOQOL-BREF. We obtained the time and frequency-domain indices of HRV, namely variance (total HRV), the low-frequency power (LF; 0.05–0.15 Hz), which may reflect baroreflex function, the high-frequency power (HF; 0.15–0.40 Hz), which reflects cardiac parasympathetic activity, and the LF/HF ratio.

Results

There was an independent contribution of HRQOL_physical to explaining the variance in HRV after excluding potential confounding factors (gender, age, physical activity, alcohol use, depression and anxiety). Compared with the participants with high levels of HRQOL_physical, those with low levels of HRQOL_physical displayed significant reductions in variance and LF.

Conclusions

This study highlights the independent role of low HRQOL_physical in contributing to the reduced HRV in healthy adults and points to a potential underlying mechanism for HRQOL_physical to confer increased risks for CVD.

Getting to the Heart of Emotion Regulation in Youth: The Role of Interoceptive Sensitivity, Heart Rate Variability, and Parental Psychopathology

Emotion regulation and associated autonomic activation develop throughout childhood and adolescence under the influence of the family environment. Specifically, physiological indicators of autonomic nervous system activity such as interoceptive sensitivity and vagally mediated heart rate variability (HRV) can inform on emotion regulation. Although the effect of parental emotion socialization on emotion regulation appears to be influenced by autonomic processes, research on physiological regulation and the influence of parental factors remains scarce. This study investigated the relationship between self-reported habitual emotion regulation strategies and HRV at rest as well as interoceptive sensitivity in forty-six youngsters (27 female; age: M = 13.00, SD = 2.13). Secondly, the association between these autonomic correlates and parental psychopathology was also studied. Whereas better interoceptive sensitivity was related to reduced maladaptive emotion regulation, specifically rumination, high HRV was related to more use of external emotion regulation strategies (i.e., support seeking). In addition, increased HRV and decreased interoceptive sensitivity were associated with maternal internalizing and there was evidence for a possible mediation effect of HRV in the relationship between maternal internalizing and child external emotion regulation. This study elucidates the link between cognitive emotion regulation strategies and underlying physiological regulation in adolescents but also indicates a putative influence of maternal internalizing symptoms on emotion regulation in their offspring.

Test-Retest Reliability of Pediatric Heart Rate Variability: A Meta-Analysis

Heart rate variability (HRV), an established index of autonomic cardiovascular modulation, is associated with health outcomes (e.g., obesity, diabetes) and mortality risk. Time- and frequency-domain HRV measures are commonly reported in longitudinal adult and pediatric studies of health. While test-retest reliability has been established among adults, less is known about the psychometric properties of HRV among infants, children, and adolescents. The objective was to conduct a meta-analysis of the test-retest reliability of time- and frequency-domain HRV measures from infancy to adolescence. Electronic searches (PubMed, PsycINFO; January 1970-December 2014) identified studies with nonclinical samples aged ≤ 18 years; ≥ 2 baseline HRV recordings separated by ≥ 1 day; and sufficient data for effect size computation. Forty-nine studies (N = 5,170) met inclusion criteria. Methodological variables coded included factors relevant to study protocol, sample characteristics, electrocardiogram (ECG) signal acquisition and preprocessing, and HRV analytical decisions. Fisher's Z was derived as the common effect size. Analyses were age-stratified (infant/toddler < 5 years, n = 3,329; child/adolescent 5-18 years, n = 1,841) due to marked methodological differences across the pediatric literature. Meta-analytic results revealed HRV demonstrated moderate reliability; child/adolescent studies (Z = 0.62, r = 0.55) had significantly higher reliability than infant/toddler studies (Z = 0.42, r = 0.40). Relative to other reported measures, HF exhibited the highest reliability among infant/toddler studies (Z = 0.42, r = 0.40), while rMSSD exhibited the highest reliability among child/adolescent studies (Z = 1.00, r = 0.76). Moderator analyses indicated greater reliability with shorter test-retest interval length, reported exclusion criteria based on medical illness/condition, lower proportion of males, prerecording acclimatization period, and longer recording duration; differences were noted across age groups. HRV is reliable among pediatric samples. Reliability is sensitive to pertinent methodological decisions that require careful consideration by the researcher. Limited methodological reporting precluded several a priori moderator analyses. Suggestions for future research, including standards specified by Task Force Guidelines, are discussed.

Linking an Anxiety-Related Personality Trait to Cardiac Autonomic Regulation in Well-Defined Healthy Adults: Harm Avoidance and Resting Heart Rate Variability

OBJECTIVE

Anxiety trait, anxiety and depression states have all been reported to increase risks for cardiovascular disease (CVD), possibly through altering cardiac autonomic regulation. Our aim was to investigate whether the relationship between harm avoidance (HA, an anxiety-related personality trait) and cardiac autonomic regulation is independent of anxiety and depression states in healthy adults.

METHODS

We recruited 535 physically and mentally healthy volunteers. Participants completed the Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI) and Tri-dimensional Personality Questionnaire. Participants were divided into high or low HA groups as discriminated by the quartile value. Cardiac autonomic function was evaluated by measuring heart rate variability (HRV). We obtained the time and frequency-domain indices of HRV including variance (total HRV), the low-frequency power (LF; 0.05-0.15 Hz), which may reflect baroreflex function, the high-frequency power (HF; 0.15-0.40 Hz), which reflects cardiac parasympathetic activity, as well as the LF/HF ratio.

RESULTS

The BDI and HA scores showed associations with HRV parameters. After adjustment for the BDI scores and other control variables, HA is still associated with reduced variance, LF and HF power. Compared with the participants with low HA, those with high HA displayed significant reductions in variance, LF and HF power and a significant increase in their LF/HF ratio.

CONCLUSION

This study highlights the independent role of HA in contributing to decreased autonomic cardiac regulation in healthy adults and provides a potential underlying mechanism for anxiety trait to confer increased risk for CVD.

Distinguishing bipolar II depression from unipolar major depressive disorder: Differences in heart rate variability

OBJECTIVES

Bipolar II (BPII) depression is commonly misdiagnosed as unipolar depression (UD); however, an objective and reliable tool to differentiate between these disorders is lacking. Whether cardiac autonomic function can be used as a biomarker to distinguish BPII from UD is unknown.

METHODS

We recruited 116 and 591 physically healthy patients with BPII depression and UD, respectively, and 421 healthy volunteers aged 20-65 years. Interviewer and self-reported measures of depression/anxiety severity were obtained. Cardiac autonomic function was evaluated by heart rate variability (HRV) and frequency-domain indices of HRV.

RESULTS

Patients with BPII depression exhibited significantly lower mean R-R intervals, variance (total HRV), low frequency (LF)-HRV, and high frequency (HF)-HRV but higher LF/HF ratio compared to those with UD. The significant differences remained after adjusting for age. Compared to the controls, the patients with BPII depression showed cardiac sympathetic excitation with reciprocal vagal impairment, whereas the UD patients showed only vagal impairment. Depression severity independently contributed to decreased HRV and vagal tone in both the patients with BPII depression and UD, but increased sympathetic tone only in those with BPII depression.

CONCLUSIONS

HRV may aid in the differential diagnosis of BPII depression and UD as an adjunct to diagnostic interviews.

Heart rate variability in major depressive disorder and after antidepressant treatment with agomelatine and paroxetine: Findings from the Taiwan Study of Depression and Anxiety (TAISDA)

Evidence from previous studies suggests that heart rate variability (HRV) is reduced in major depressive disorder (MDD). However, whether this reduction is attributable to the disorder per se or to medication, since antidepressants may also affect HRV, is still debated. There is a dearth of information regarding the effects of agomelatine, a novel antidepressant, on HRV. Here, we investigated whether HRV is reduced in MDD and compared the effects of agomelatine and paroxetine on HRV. We recruited 618 physically healthy unmedicated patients with MDD and 506 healthy volunteers aged 20-65 years. Frequency-domain measures of resting HRV were obtained at the time of enrollment for all participants. For patients with MDD, these measures were obtained again after 6 weeks of either agomelatine or paroxetine monotherapy. Compared with healthy subjects, unmedicated patients with MDD exhibited significantly lower variance (total HRV), low frequency (LF), and high frequency (HF) HRV, and a higher LF/HF ratio. Depression severity independently contributed to decreased HRV and vagal tone. Fifty-six patients completed the open-label trial (n=29 for agomelatine, n=27 for paroxetine). Between-group analyses showed a significant group-by-time interaction for LF-HRV and HF-HRV, driven by increases in LF-HRV and HF-HRV only after agomelatine treatment. Within the paroxetine-treated group, there were no significant changes in mean R-R intervals or any HRV indices. We therefore concluded that MDD is associated with reduced HRV, which is inversely related to depression severity. Compared with paroxetine, agomelatine has a more vagotonic effect, suggesting greater cardiovascular safety. Clinicians should consider HRV effects while selecting antidepressants especially for depressed patients who already have decreased cardiac vagal tone.

Impaired cardiac autonomic nervous system function is associated with pediatric hypertension independent of adiposity

BACKGROUND

We examined whether sympathetic nervous system activity influences hypertension status and systolic blood pressure (SBP) independent of adiposity in youth ranging from normal-weight to severe obesity.

METHODS

We examined the association of heart rate variability (HRV) with hypertension status and SBP among youth (6-18 y old; n = 188; 103 female). Seated SBP was measured using an automated cuff. Prehypertension (SBP percentile ≥ 90th to <95th) and hypertension (SBP percentile ≥ 95th) were defined by age-, sex-, and height-norms. Autonomic nervous system activity was measured using HRV via SphygmoCor MM3 system and analyzed for time- and frequency-domains. Total body fat was measured via dual-energy X-ray absorptiometry.

RESULTS

Logistic regression models demonstrated lower values in each time-domain HRV measure and larger low-frequency (LF):high-frequency (HF) ratio to be significantly associated with higher odds of being prehypertensive/hypertensive (11-47% higher odds) independent of total body fat (P < 0.05). In linear regression analysis, lower time-domain, but not frequency-domain, HRV measures were significantly associated with higher SBP independent of total body fat (P < 0.05).

CONCLUSION

These data suggest that impaired cardiac autonomic nervous system function, at rest, is associated with higher odds of being prehypertensive/hypertensive and higher SBP which may be independent of adiposity in youth.

Effects of exercise on cardiac autonomic modulation in children: literature update

AbstractIntroduction It is known that physical exercise is beneficial and precipitates adjustments to the autonomic nervous system. However, the effect of exercise on cardiac autonomic modulation in children, despite its importance, is poorly investigated.Objective To bring together current information about the effects of exercise on heart rate variability in healthy and obese children.Methods The literature update was performed through a search for articles in the following databases; PubMed, PEDro, SciELO and Lilacs, using the descriptors “exercise” and “child” in conjunction with the descriptors “autonomic nervous system”, “sympathetic nervous system”, “parasympathetic nervous system” and also with no descriptor, but the key word of this study, “heart rate variability”, from January 2005 to December 2012.Results After removal of items that did not fit the subject of the study, a total of 9 articles were selected, 5 with healthy and 4 with obese children.Conclusion The findings suggest that exercise can act in the normalization of existing alterations in the autonomic nervous system of obese children, as well as serve as a preventative factor in healthy children, enabling healthy development of the autonomic nervous system until the child reaches adulthood.

Different Patterns of Heart Rate Variability During Acute Withdrawal in Alcohol Dependent Patients With and Without Comorbid Anxiety and/or Depression

Abstract. The aim of the present study was to examine cardiac autonomic function during acute alcohol withdrawal (AW) in two clinical subgroups with alcohol dependence. To this end we compared 24 patients with pure alcohol dependence (Pure ALC) with 24 alcohol-dependent patients who had comorbid symptoms of anxiety and/or depression (ANX/DEP ALC) on their mean heart rate and several (spectral) measures of heart rate variability (HRV) obtained from the patients when they were withdrawn from alcohol. To elucidate the contribution of anxiety and depression to the cardiac measures we moreover compared these groups to 120 non-comorbid patients with major depressive disorder (MDD), 24 patients with anxiety disorders and 120 matched controls. The Hamilton Depression Rating Scale (HAM-D) and the Hamilton Anxiety Rating Scale (HAM-A) were employed for the clinical symptom ratings. The cardiac measures were found to significantly discriminate among the groups (Hotelling-Lawley F = 3.18, p < .001). Post hoc testing revealed that total HRV (variance in interbeat intervals) was reduced in Pure ALC (p = .033, Cohen’s d = −0.51), ANX/DEP ALC (p < .001, Cohen’s d = −1.33), MDD (p < .001, Cohen’s d = −0.66), and anxiety disorders (p = .002, Cohen’s d = −0.69), relative to controls. When these comparisons were adjusted for smoking history in pack-years, the results were unchanged. The ANX/DEP ALC patients showed significantly greater reduction in total HRV and high frequency (HF)-HRV compared with the Pure ALC patients. Both anxiety and depression moderated the influence of alcohol use and withdrawal on resting HRV. Our results suggest that compared to Pure ALC, ANX/DEP ALC presents a subtype of alcohol dependence with higher vulnerability to reduced HRV during acute AW. Implications for cardiovascular risk are discussed.

Are smoking and passive smoking related with heart rate variability in male adolescents?

Objective

To analyze the relation between smoking and passive smoking with heart rate variability parameters in male adolescents.

Methods

The sample consisted of 1,152 males, aged 14 and 19 years. Data related to smoking and passive smoking were collected using a questionnaire. RR intervals were obtained by a heart rate monitor, on supine position, for 10 minutes. After collecting the RR intervals, time (standard deviation of all RR intervals, root mean square of the squared differences between adjacent normal RR intervals and the percentage of adjacent intervals over 50ms) and frequency domains (low and high frequency and sympathovagal balance) parameters of heart rate variability were obtained.

Results

No significant differences between smoker and nonsmoker adolescents were observed in heart rate variability parameters (p>0.05). Similarly, heart rate variability parameters did not show significant difference between exposed and not exposed to passive smoking (p>0.05).

Conclusion

Cigarette smoking and passive smoking are not related to heart rate variability in adolescence.

Short-term heart rate variability in a population-based sample of 10-year-old children

Heart rate variability (HRV) is a non-invasive quantitative marker of cardiac autonomic function derived from continuous electrocardiogram (ECG) recordings. Normative HRV values and development factors have not been established in pediatric populations. The objective was to derive referent time- and frequency-domain HRV values for a population-based sample of children. Children aged 9-11 years (N = 1,036) participated in the Québec Longitudinal Study of Child Development cohort cardiovascular health screening. Registered nurses measured anthropometrics (height, weight) and children wore an ambulatory Holter monitor to continuously record an ECG signal. HRV variables included time (SDNN, pNN50, RMSSD, SDANN) and frequency (HF, LF, LF/HF ratio) domain variables. Normative HRV values, stratified by age, sex, and heart rate, are presented. Greater heart rate (β avg  = -0.60, R avg (2)  = 0.39), pubertal maturation (β avg = -0.11, R avg (2)  = 0.01), later ECG recording times (β avg = -0.19, R avg (2)  = 0.07), and higher diastolic blood pressure (β avg = -0.11, R avg (2)  = 0.01) were significantly associated with reduced HRV in 10-year-old children. The normative HRV values permit clinicians to monitor, describe, and establish pediatric nosologies in primary care and research settings, which may improve treatment of diseases associated with HRV in children. By better understanding existing values, the practical applicability of HRV among clinicians will be enhanced. Lastly, developmental (e.g., puberty) and procedural (e.g., recording time) factors were identified that will improve recording procedures and interpretation of results.

Heart rate variability and cardiovascular risk factors in adolescent boys

OBJECTIVE

To establish reference values of heart rate variability (HRV) measures in a cohort of adolescent boys and to determine the relationship between HRV and the clustering of risk factors (RFs) for cardiovascular disease.

STUDY DESIGN

This cross-sectional study included 1152 adolescent boys (age: 16.6 ± 1.2 years old). Demographic data, health-related habits, obesity indicators, and blood pressure were evaluated. HRV measures of time (SD of all RR intervals, root mean square of the squared differences between adjacent normal RR intervals, and the percentage of adjacent intervals over 50 ms) and frequency domains were assessed (low [LF] and high [HF] frequency).

RESULTS

The components of HRV were RR interval (827 ± 128 ms), SD of all RR intervals (61.9 ± 23.5 ms), root mean square of the squared differences between adjacent normal RR intervals (54.5 ± 29.4 ms), percentage of adjacent intervals over 50 ms (29.4 ± 20.4%), LF (53 ± 16 nu), HF (47 ± 16), and LF/HF (1.44 ± 1.08). Greater sympathetic and lower parasympathetic modulation at rest were associated with higher adiposity, higher blood pressure and physical inactivity. Adolescents with 2 or more RFs also presented lower HRV than subjects with no RFs (P < .001).

CONCLUSIONS

The study has provided descriptive indicators that help the interpretation of HRV results in adolescents. Lower HRV measures are associated with the clustering of cardiovascular RFs.

Heart rate variability in unmedicated patients with bipolar disorder in the manic phase

AIMS

Decreased heart rate variability (HRV) has been proposed in bipolar disorder. To date, there has been no adequate study that has investigated resting HRV in unmedicated patients with bipolar disorder in the manic state.

METHODS

To examine whether bipolar mania is associated with decreased HRV, 61 unmedicated patients with bipolar mania and 183 healthy volunteers aged 20-65 years were recruited for this case-control analysis. The Young Mania Rating Scale (YMRS), Clinical Global Impression-Severity, Hamilton Depression Rating Scale (HAM-D), and Hamilton Anxiety Rating Scale (HAM-A) were used for the clinical ratings. Cardiac autonomic function was evaluated by measuring HRV parameters and the frequency-domain indices of HRV were obtained.

RESULTS

Patients with bipolar mania exhibited significantly lower mean RR interval, variance, low-frequency (LF)-HRV, and high-frequency (HF)-HRV but higher LF/HF compared to controls. Decreased HRV (variance) was associated with the YMRS total scores. Both the YMRS total scores and the Clinical Global Impression-Severity scores were positively correlated with the LH/HF ratio and inversely correlated with the HF-HRV. There was no significant correlation between the HAM-D/HAM-A scores and any HRV parameter.

CONCLUSIONS

Bipolar mania is associated with cardiac autonomic dysregulation, highlighting the importance of assessing HRV in manic patients. Further studies examining the influence of anti-manic psychotropic drugs on cardiac autonomic regulation in bipolar mania are needed.

Adolescent girls with emotional disorders have a lower end-tidal CO2 and increased respiratory rate compared with healthy controls

Hyperventilation has been linked to emotional distress in adults. This study investigates end-tidal carbon dioxide (ETCO₂), respiratory rate (RR), and heart rate variability (HRV) in adolescent girls with emotional disorders and healthy controls. ETCO₂, RR, HRV, and ratings of emotional symptom severity were collected in adolescent female psychiatric patients with emotional disorders (n = 63) and healthy controls (n = 62). ETCO₂ and RR differed significantly between patients and controls. ETCO₂, HR, and HRV were significant independent predictors of group status, that is, clinical or healthy, while RR was not. ETCO₂ and RR were significantly related to emotional symptom severity and to HRV in the total group. ETCO₂ and RR were not affected by use of selective serotonin reuptake inhibitors. It is concluded that emotional dysregulation is related to hyperventilation in adolescent girls. Respiratory-based treatments may be relevant to investigate in future research.

Pro-inflammatory cytokines are elevated in adolescent females with emotional disorders not treated with SSRIs

BACKGROUND

Adults with major depressive disorder (MDD) show elevated levels of IL-6 and TNF-alpha. Studies of adolescents with MDD or anxiety disorders (AD) are few and present conflicting results.

METHODS

We studied plasma cytokines in a clinical sample of adolescent females with MDD and/or clinical AD (n=60, mean age 16.8 years), compared to healthy controls (n=44; mean age 16.5 years).

RESULTS

The clinical sample showed significantly higher values of IL-2 (Z=-4.09, p>0.0001), IL1-beta (Z=-2.40, p<0.05) and IL-10 (Z=-2.38, p<0.05) as compared to controls. The subgroup of the clinical sample not treated with SSRIs had a significant difference of IL-6 (Z=-2.26, p<0.05) in addition to the difference of IL-2 and IL1-beta, but showed no difference of IL-10 as compared to the controls. SSRI treatment was related to IL-6, explaining 26% of the variance in the clinical sample after controlling for BMI and symptom severity. In the clinical sample, levels of IL-6 and IFN-gamma were positively correlated with self-assessed symptoms of anxiety and/or depression (corr.coeff 0.35 resp 0.40 at p<0.05).

LIMITATIONS

The cross-sectional design does not allow for conclusions on causality. The sample sizes were relatively small and a large drop-out in the clinical sample may have influenced the representativity.

DISCUSSION

The study suggests that pro-inflammatory cytokines are part of the pathophysiology of emotional disorders in adolescent females and that SSRIs have anti-inflammatory properties. The findings prompt further studies on the specific mechanisms involved and may contribute to the development of more effective treatment and prevention.

Heart rate variability (HRV) in adolescent females with anxiety disorders and major depressive disorder

Aim:

The aim of this study was to investigate heart rate variability (HRV) in a clinical sample of female adolescents with anxiety disorders (AD) and/or major depressive disorder (MDD) compared with healthy controls and to assess the effect of selective serotonin reuptake inhibitors (SSRI) on HRV.

Methods:

Heart rate variability was measured in adolescent female psychiatric patients with AD and/or MDD (n = 69), mean age 16.8 years (range: 14.5–18.4), from 13 out-patient clinics and in healthy controls (n = 65), mean age 16.5 years (range: 15.9–17.7). HRV was registered in the sitting position during 4 min with no interventions.

Results:

Logarithmically transformed high frequency HRV (HF), low frequency HRV (LF) and standard deviation of inter beat intervals (SDNN) were lower in the clinical sample compared with the controls (Cohen’s d for HF = 0.57, LF = 0.55, SDNN = 0.60). This was not explained by body mass index, blood pressure or physical activity. Medication with SSRI explained 15.5% of the total variance of HF, 3.0% of LF and 6.5% of SDNN.

Conclusions:

Adolescent female psychiatric patients with AD and/or MDD show reduced HRV compared with healthy controls. Medication with SSRI explained a part of this difference.