Heart Rate Variability In Adolescents Research Articles

Lipid profile, inflammatory biomarkers, endothelial dysfunction, and heart rate variability in adolescents with type 1 diabetes. A case-control study among UAE population

BackgroundType 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by the chronic inflammation and cause of endothelial dysfunction (ED). Heart rate variability (HRV) is a marker of sympathetic and parasympathetic autonomic nervous system dysfunction. We investigated the association of lipid profile, inflammatory biomarkers, endothelial dysfunction, and heart rate variability in adolescents with T1DM among UAE population. MethodIn this case-control study we recruited 126 adolescents (13–22 years) from Abu Dhabi, UAE (United Arab Emirates). Demographic, anthropometric, blood and urine samples were collected after an overnight fasting. HRV measurements were determined per Task Force recommendations. Independent t-test or Mann-Whitney U test and Pearson's Chi-squared test were used to compare groups. Adjusted conditional logistic regression model was used to identify the determinants independently associated with T1DM. ResultsThe mean ages in control (n = 47) and patient (n = 79) groups were 17.5 ± 4.6 and 18.6 ± 4.8 years, respectively. A family history of diabetes and waist and hip circumferences significantly differed between the groups (p = 0.030 and 0.010). The patients with T1DM exhibited significantly higher levels of atherogenic markers than control. Endothelial dysfunction biomarkers such as levels of sICAM-1 (p < 0.001), adiponectin (p < 0.001) and 25-hydroxyvitamin D (p < 0.001) were significantly different in the control group compared with those in the T1DM group. There was a significant difference in SDNN intervals, NN50, pNN50, and SD1/SD2 among the two groups. In adjusted analysis, total cholesterol (adjusted Odds Ratio (aOR): 2.78, 95 % CI:1.37–5.64; p = 0.005), LDL (2.66, 95%CI:1.19–5.92; p = 0.017), and triglycerides (5.51, 95%CI:1.57–19.41; p = 0.008) were significantly associated with developing T1DM. The HRV indicators were significantly associated with decrease odds of T1DM after controlling for SBP, BMI, and family history of DM. ConclusionIn this study, adolescents with T1DM showed a significant association with lipid profile, ED, and HRV compared with controls. Thus, an early attention to diabetes control is required to reduce the risk of cardiac autonomic neuropathy leading to various cardiovascular diseases.

Time course efficiency of MICE and HIIE on inhibitory control and HRV in adolescents with obesity and different cardiorespiratory fitness.

Adolescent obesity is associated with impaired inhibitory control. Acute exercise can improve executive function. However, due to the influence of exercise intensity, cognitive test timing, and cardiorespiratory fitness (CF) level, the most effective exercise program remains controversial. The current study investigated the time-course effects of moderate-intensity continuous exercise (MICE) and high-intensity interval exercise (HIIE) on inhibitory control (Stroop) and task-related heart rate variability (HRV) in adolescents with different CF. A mixed experimental design of 2 CF levels (high CF, HCF; low CF, LCF) × 3 exercise methods (MICE, HIIE, CON) × 3 test timing (pre, post-0, post-20) was adopted. Heart rate variability (HRV) and Stroop task tests were conducted before exercise (pre), immediately after exercise (post-0), and 20 min after exercise (post-20). Individuals with HCF exhibited a positive decrease in Stroop response time immediately and 20 min after MICE and HIIE, compared to pretest response times (RT). Conversely, individuals with LCF showed a slight increase in Stroop task (RT) only immediately after HIIE. All individuals had a slight increase in ACC after MICE and HIIE compared to before exercise. In addition, compared with the control group, the time-domain index (the square root of the mean squared differences of successive NN intervals, RMSSD) of HRV was significantly decreased, the frequency-domain index (the absolute power of the Low-Frequency band/the absolute power of the High-Frequency band ratio, LF/HF) was significantly increased after MICE and HIIE, and the effect of HIIE on RMSSD and LF/HF was significantly greater than that of MICE. The current study found that the acute effects of MICE and HIIE on inhibitory control in obese adolescents were influenced by the interaction of cognitive test timing and cardiorespiratory fitness. Individuals with high cardiorespiratory fitness performed better on the Stroop task than individuals with low cardiorespiratory fitness. The inhibitory control of HIIE in high-cardiorespiratory obese adolescents produced positive effects similar to those in MICE but more lasting, suggesting that HIIE is more beneficial for high-cardiorespiratory obese adolescents. MICE promoted inhibitory control in obese adolescents with low cardiorespiratory fitness, but HIIE impaired inhibitory control in obese adolescents with low cardiorespiratory fitness immediately after exercise, suggesting that low cardiopulmonary fitness obese adolescents may be suitable for MICE rather than HIIE exercise intervention. The shift from balanced HRV to sympathetic dominance after acute exercise reflects increased arousal levels and may be one of the underlying mechanisms by which acute exercise brings benefits to executive function.

0114 Interplay of School and Free Days on the Association of Circadian Misalignment with Heart Rate Variability in Adolescents

Abstract Introduction The circadian timing system, which governs the sleep-wake cycle, is involved in cardiometabolic and autonomic regulation. Heart rate variability (HRV), a marker of cardiac autonomic modulation (CAM), is known to predict cardiovascular morbidity. Therefore, circadian misalignment of the sleep-wake cycle, which is highly prevalent in adolescents and may express differently if youth are in school or free-days, is likely to impact CAM. We examined whether deviations in the circadian timing of sleep are associated with blunted HRV in adolescents as a function of being entrained to school or not. Methods We studied 337 population-based randomly-selected adolescents from the Penn State Child Cohort (median 16 years; 47% female; 21% racial/ethnic minority) who had at least 3-night at-home actigraphy (ACT), in-lab 9-h polysomnography (PSG) and 24-h Holter-monitoring heart rate variability (HRV) data. ACT-measured sleep midpoint (SM) was calculated as the midpoint of the sleep period for weekdays (5-nights) and weekends (2-nights), whereas ACT-measured sleep regularity (SR) was calculated as the intra-individual standard deviation of the SM across 5- and 7-nights. Frequency and time-domain HRV indices were primary outcomes. Linear regression models were stratified by “in school” and “on break” to test SM and SR as predictors of HRV indices while accounting for sex, race/ethnicity, age, BMI percentile, ACT-sleep duration, ACT-sleep variability, and PSG-apnea/hypopnea index. Results Lower SR on schooldays was associated with lower nighttime Log-HF, Log-LF and SDNN, yet higher HR (all p&amp;lt; 0.01); e.g., each standard deviation increase in SR on schooldays (i.e., 45m higher) was associated with -7.15ms (2.57) in nighttime SDNN (p=0.006). A later SM on free weekends was associated with lower nighttime Log-HF, Log-LF, SDNN and RMSSD, yet higher HR and LF-HF ratio (all p&amp;lt; 0.03); e.g., each standard deviation increase in SM on free weekends (i.e., 1.5h later) was associated with -7.33ms (2.85) in nighttime RMSSD (p=0.011). Conclusion A delayed and an irregular sleep midpoint during breaks and during schooldays, respectively, were associated with impaired CAM in adolescents. These data suggest that not only circadian misalignment contributes to adverse cardiovascular outcomes but its distinct metrics require measurement under different entrainment conditions in adolescents. Support (if any) NIH (R01HL136587,R01MH118308,UL1TR000127), American Heart Association (23PRE1011962).

Community and domestic violence are associated with DNA methylation GrimAge acceleration and heart rate variability in adolescents

ABSTRACT Background: Cumulative exposure to violence can change the regulation of epigenetic and physiological markers. Although violence has been associated with accelerated cellular aging, little is known about associations with cardiac autonomic activity. Objective: The current study aimed to investigate the relationship of exposure to community and domestic violence (CDV) with vagal activity and epigenetic aging acceleration. Methods: A total of 86 adolescents (57% female) were evaluated and interviewed at two time-points in São Gonçalo (2014–2019), a Brazilian city with high levels of violence. Exposure to CDV was assessed in both time-points. GrimAge acceleration was calculated from saliva DNA methylation using Infinium HumanMethylation450K (Illumina) collected in the first assessment. Heart rate variability (HRV) was collected during two stress tasks at the second assessment. Results: The exposure to violence witnessed or directly experienced at home and in the community increased significantly (t = 4.87, p < .01) across two-time points, and males had reported higher violence exposure (t = 2.06, p = .043). Violence at 1st assessment was significantly associated with GrimAge acceleration (B = .039, p value = .043). Violence at both assessments were associated with HRV measured during the narration of the worst trauma (traumaHRV) (B = .009, p value = .039, and B = .007, p value = .024, 1st and 2nd assessment respectively). GrimAge acceleration was significantly associated with traumaHRV (B = .043, p value = .049), and HRV measured during a 3D roller coaster video (B = .061, p value = .024). Conclusions: We found relevant evidence that experiencing violence during adolescence is associated with epigenetic aging and stress-related vagal activity. Understanding these factors during this period could contribute to the development of early interventions for health promotion. HIGHLIGHTS Higher exposure to Community and domestic violence is associated with increased GrimAge acceleration. Higher GrimAge acceleration is associated with increased stress-related vagal activity. Exposure to community and domestic violence increased significantly over time.

Abstract MP47: Sleep Disordered Breathing is Adversely Associated With Cardiac Autonomic Modulation in Adolescents

Introduction: Sleep disordered breathing (SDB), as measured by the apnea/hypopnea index (AHI), is a known risk factor for cardiovascular disease (CVD) in adults. Although SDB is prevalent in pediatric populations, there has been less focus on SDB as a primary risk factor for CVD in youth. The recent AHA scientific statement on SDB and CVD in children and adolescents suggests that, in order to better understand the long-term CVD-related risk associated with SDB in youth, additional longitudinal studies incorporating noninvasive markers of CVD are needed. The current study aimed to fill this important gap. Hypothesis: We hypothesized that SDB is associated with decreased HRV in adolescents. Methods: We studied 421 subjects from the Penn State Child Cohort who were 8.7 (1.7) years old at baseline and were followed-up as adolescents 16.5 (2.3) years old. We estimated the AHI from 9-hour, in-lab polysomnography (PSG), and frequency and time-domain heart rate variability (HRV) indices from 24-h Holter EKG monitoring immediately following PSG. We stratified 24-h HRV data into daytime and nighttime periods. Linear regression analyses examined the association between AHI with 24-h HRV indices, while adjusting for age, sex, race/ethnicity, BMI percentile, and metabolic syndrome (MetS) score in adolescence as well as AHI and nighttime HRV indices in childhood. Results: While there were no significant associations between AHI and daytime (p=0.233) or nighttime (p=0.147) HR, there were significant associations with frequency and time-domain HRV indices. A higher AHI was associated with lower Log-HF, Log-LF, SDNN and RMSSD, yet higher LF/HF, for both daytime and nighttime periods (all p&lt;0.05). For example, for each additional apnea or hypopnea per hour of sleep there was a decrease of -1.74ms (0.73) and -1.65ms (0.77) in SDNN during the daytime (p=0.018) and nighttime (p=0.033), respectively, even after adjusting for all covariates including MetS, childhood AHI and SDNN. More specifically, the 24-h SDNN of adolescents with an AHI≥5, indicative of moderate-to-severe SDB, was 10.9ms (4.4) lower than that of adolescents with an AHI=0 (p=0.014). Conclusions: SDB is associated with impaired cardiac autonomic balance in adolescence independently of MetS, prior SDB and prior HRV status. These data further support the role of SDB as an independent risk factor for CVD early in life.

Abstract 13: Circadian Misalignment is Associated With Impaired Heart Rate Variability in Adolescents

Introduction: Adequate sleep has been recognized by AHA as part of Life’s Essential 8 in the prevention of cardiovascular disease (CVD). The circadian system, which governs the sleep-cycle, is also involved in cardiac, metabolic and autonomic regulation. Heart rate variability (HRV), a marker of cardiac autonomic modulation (CAM), is known to predict CVD. As a result, circadian misalignment of the sleep-wake cycle, which is highly prevalent in adolescents, may impact CAM and be a potential risk factor for adverse CVD outcomes in early life. Hypothesis: We hypothesize that deviations in the circadian timing of sleep are associated with blunted HRV in adolescents. Methods: We analyzed data from 337 population-based randomly-selected adolescents from the Penn State Child Cohort (median 16 years; 47% female; 21% racial/ethnic minority) who had at least 3-night at-home actigraphy (ACT), in-lab 9-h polysomnography (PSG) and 24-h Holter-monitoring heart rate variability (HRV) data. ACT-sleep duration and sleep midpoint (SM) were calculated as the intra-individual mean total sleep time and midpoint of the sleep period, respectively. ACT-sleep variability and sleep regularity (SR) were calculated as the intra-individual standard deviation of sleep duration and sleep midpoint across nights, respectively. Frequency and time-domain HRV indices, including HR oscillations at high frequencies (HF), standard deviation between normal heart beats or R-R intervals (SDNN), and root mean square of successive differences between normal heartbeats (RMSSD), were primary outcomes. Linear regression models tested SM and SR as predictors of HRV indices, while accounting for sex, race/ethnicity, age, body mass index, ACT-sleep duration, ACT-sleep variability, and PSG-apnea/hypopnea index. Results: While there were no meaningful associations between SM or SR with daytime HRV, there were significant associations between SM with nighttime HRV. A later SM was associated with lower nighttime Log-HF, SDNN and RMSSD, yet higher nighttime LF/HF (all p&lt;0.03). For each standard deviation increase in SM (i.e., 1.5 hours later), there was a decrease of -5.50ms (1.92) in nighttime RMSSD (p=0.004). More specifically, the nighttime RMSSD of adolescents with a SM at 5:30 (i.e., sleep onset at 2:00, sleep offset at 9:00), was 18.2ms (6.7) lower (p=0.007) than that of adolescents with a SM at 2:30 (i.e., sleep onset at 23:00, sleep offset at 6:00). Conclusions: A delayed sleep phase is associated with impaired CAM in adolescents. These data support that circadian misalignment of the sleep-wake cycle may independently contribute to CVD risk.

Association between frequency of physical education classes and heart rate variability in adolescents boys: a cross-sectional study

Physical inactivity is associated with low heart rate variability (HRV) in adolescents. However, whether the number of physical education (PE) classes impact HRV remains unclear. This cross-sectional study verified the association between the frequency of PE classes and HRV parameters in male adolescents. This study included 1152 boys (16.6 ± 1.2 years). The quantity of PE classes was assessed though questionnaire and the adolescents were stratified accordingly (no PE class; one PE class/wk; ≥2 PE classes/wk). Time- (SDNN, RMSSD, PNN50) and frequency-domains (LF, HF, sympathovagal balance) of HRV were obtained. Generalized Linear Models were used for comparing the HRV parameters according to the quantity of PE classes, adjusting for confounders. There was no difference in HRV measures of time: (SDNN, p = 0.77; RMSSD, p=0.72; PNN50, p=0.83) and frequency (LF, p=0.61; HF, p=0.61; sympathovagal balance, p=0.60) between the different frequencies of PE classes. The frequency of PE classes in not associated with HRV parameters of male adolescents.

The peculiarities of the heart rate regulation in boys and girls with different body composition, motor and eating behavior

BACKGROUND: There are a lot of works devoted to the study of the main regularities of the heart rate (HR) control in individuals depending on the body weight. Still, there are some uncleared and even controversial issues that significantly influence the notion of this process itself. Particularly, impaired HR variability in patients with the cardiometabolic syndrome is characterized by the weakening of the impact of both parasympathetic and sympathetic branches of the autonomic nervous system. The works devoted to the heart rate variability features in young people associated with the body weight are scarce.AIM: To study the peculiarities of the heart rate variability in boys and girls with different body composition, motor and eating behavior.MATERIALS AND METHODS: A cross-sectional, open, single-arm, non-randomized study of the HR variability in adolescents with different body fat mass (BFM) was carried out on the basis of the Center for Healthy Nutrition of Altai State University. The HR variability, nutritional status and physical activity index (PHAI) were studied in the groups of individuals with different body fat mass.RESULTS: We examined 168 people (85 boys and 83 girls). The surveyed belonged to the adolescent age period (boys from 17 to 21 years old, girls from 16 to 20 years old). The boys and girls examined by us had a different amount of BFM %. The HR variability, nutritional status and physical activity index were studied in 44 people with the low BFM, 71 people with the average BFM, 53 people with the increased BFM. In both sexes, the group with the increased BFM features an increase in the absolute (HF, ms2 ) and relative (HF%) oscillation power of the heart rate high-frequency component. The average value of the physical activity index in the group with the reduced BFM equals 1.52 ± 0.037 in boys, and 1.44 ± 0.099 in girls. The average value of the physical activity index in the group with the average BFM is 1.44 ± 0.029 and 1.42 ± 0.095 in boys and in girls respectively. The average value of the physical activity index in the group with the increased BFM is 1.23 (Q25–75 1.20–1.70) in boys, and 1.26 ± 0.33 in girls. The representatives of the group with the increased BFM have a higher caloric value (CV) of the daily intake. In young men, a higher CV was achieved due to increased consumption of fats and carbohydrates. In the girls of the third group, a higher CV of the daily intake was gained due to proteins, fats, carbohydrates.CONCLUSION: The results of the HR variability showed that the motor and eating behavior affect the state of the cardiac function in both boys and girls. An increase in the body fat mass in the individuals with a maximum CV of the daily intake and a minimum level of motor activity is associated with the prevalence of the parasympathetic branch of the autonomic nervous system in the heart rate control.

Sleep quality and heart rate variability in adolescents with type 1 or type 2 diabetes.

Decreased sleep quality and lower heart rate variability (HRV) have both independently been associated with diabetes and may contribute to risks for cardiovascular disease. Although poor sleep quality has been associated with lower HRV in adults with type 2 diabetes (T2D), studies of sleep quality in adolescents with (T2D) or studies examining the possible association of poor sleep quality with lower HRV in adolescents with T2D or T1D are not available. Thus, we conducted a secondary analysis of data from an existing study to determine if there were associations between sleep quality and HRV in adolescents with T1D or T2D. Adolescents with T1D (n=101) or T2D (n=37) completed 24-h HRV Holter monitoring and analysis and a self-reported global measure of sleep quality. Poor sleep quality was significantly associated with lower HRV, a known predictor for CV risk. Those with T2D had lower measures of HRV. The evaluation of sleep quality and early signs of cardiovascular autonomic changes should be considered in routine assessments of adolescents with diabetes. Future research is warranted to examine more robust measures of sleep and HRV in adolescents with diabetes.

Brain structure and parasympathetic function during rest and stress in young adult women.

Heart rate variability (HRV) is an important biomarker for parasympathetic function and future health outcomes. The present study examined how the structure of regions in a neural network thought to maintain top-down control of parasympathetic function is associated with HRV during both rest and social stress. Participants were 127 young women (90 Black American), who completed a structural MRI scan and the Trier Social Stress Test (TSST), during which heart rate was recorded. Regression analyses were used to evaluate associations between cortical thickness in five regions of the Central Autonomic Network (CAN; anterior midcingulate cortex [aMCC], pregenual and subgenual anterior cingulate cortex [pgACC, sgACC], orbitofrontal cortex [OFC], and anterior insula) and high-frequency HRV during rest and stress. Results indicated that cortical thickness in CAN regions did not predict average HRV during rest or stress. Greater cortical thickness in the right pgACC was associated with greater peak HRV reactivity during the TSST, and survived correction for multiple comparisons, but not sensitivity analyses with outliers removed. The positive association between cortical thickness in the pgACC and peak HRV reactivity is consistent with the direction of previous findings from studies that examined tonic HRV in adolescents, but inconsistent with findings in adults, which suggests a possible neurodevelopmental shift in the relation between brain structure and autonomic function with age. Future research on age-related changes in brain structure and autonomic function would allow a more thorough understanding of how brain structure may contribute to parasympathetic function across neurodevelopment.

Sex Moderates the Relationship Between Nausea Severity and Heart Rate Variability in Adolescents and Young Adults.

Nausea is a common complaint among children and is particularly prevalent in children with functional abdominal pain (FAP), with nearly half of children with FAP also endorsing nausea. Dysfunction of the autonomic nervous system, which can be indexed by heart rate variability (HRV), leads to abnormalities in gastric electrical activity that are associated with GI symptoms. To evaluate that relationship between nausea severity and HRV in adolescents and young adults with a history of FAP and to assess for sex differences. Participants were pediatric patients with a diagnosis of FAP who were recruited from a pediatric GI clinic between 1993 and 2007 for a prospective study of the course of FAP. Study analyses focused on the cross-sectional relationship between HRV, indexed by standard deviation of the R-R interval (SDRRI) and high-frequency (HF) power, and nausea severity collected during a follow-up visit in late adolescence and young adulthood. Controlling for age and BMI, a significant nausea by sex interaction emerged for both SDRRI and HF power. Tests of conditional effects of nausea by sex showed that the inverse relation between nausea severity and both SDRRI and HF was significant for females but not for males. This is the first study to evaluate the relationship between nausea severity and HRV. Greater nausea severity was associated with lower HRV in females but not in males. Further validation of these results may provide insight into novel treatment approaches for females with nausea that target vagal tone.

Diagnosis and management of an inappropriate sinus tachycardia in adolescence based upon a Holter ECG: A retrospective analysis of 479 patients.

Inappropriate sinus tachycardia (IST) is a common disease of the autonomic nervous system in children and adults. Diagnosis and treatment of IST in adolescents is not well defined. In this retrospective study, we tested our hypothesis regarding autonomic dysfunction in childhood by analyzing 24-h heart rate variability (HRV) in 479 children, with a mean age of 13.7 ± 2.1 years, who were referred to the outpatient clinic in the Pediatrics Department within the last 15 years. Seventy-four adolescents with a mean 24-h heart rate ≥ 95 bpm (our cut-off for an IST based upon 66 healthy controls) were deemed to have IST. We found the risk of IST to be high in adolescents with attention deficit disorder (OR = 3.5,p<0.001), pre-hypertension (OR = 2.5, p = 0.043) and hypertension (OR = 2.1,p = 0.02); insignificantly enhanced in children with short stature (OR = 1.9,p = 0.19), surgically-treated congenital heart disease (OR = 1.4,p = 0.51) and obesity without hypertension (OR = 1.4;p = 0.25); and negligible in adolescents with anorexia nervosa (OR = 0.3, p = 0.26) and constitutional thinness (OR = 0.9,p = 0.89). IST was associated with a significant decrease in global HRV and elevated blood pressures, indicating an enhanced cardiovascular risk. Methylphenidate did not increase 24-h heart rates, whereas omega-3 fatty acid supplementation significantly decreased elevated heart rates and increased HRV in adolescents with IST. In this retrospective analysis, 15.4% of adolescents suffered from IST with a 24-h heart rate ≥ 95 bpm, predominately due to attention deficit disorder and hypertension.

Getting to the heart of food craving with resting heart rate variability in adolescents

BackgroundThere is an epidemic of obesity in children and adolescents. Research into the self-regulatory factors that drive eating behavior is of critical importance. Food craving contributes to overeating and difficulty with weight loss and is strongly correlated with self-regulation. High-frequency heart rate variability (HF HRV) reflects parasympathetic activity and is positively associated with self-regulation. Few studies of HF HRV and food craving have been conducted in adolescents. The current study examined the association between HF HRV and food craving in a large-scale sample of healthy adolescents. MethodElectrocardiogram (ECG) was recorded in 134 healthy adolescents aged 10–17 during a 7-min resting state. Participants also completed the Food Craving Questionnaire-Trait (FCQ-T). The relative power of HF HRV was calculated. Association between HF HRV and food craving was examined in the context of sex and age. Next, the relative significance of all food craving subscales was considered in relation to HF HRV. ResultsHF HRV was inversely correlated with food craving, taking into account sex and age. Considering all the subscales of FCQ-T in relation to HF HRV, the “lack of control over eating” subscale accounted for the most significant variance. ConclusionThis was the first study to evaluate resting HRV and eating behaviors in a large-scale adolescent sample. HF HRV was negatively associated with food craving, with lower HF HRV correlating with higher food craving, especially in the context of diminished control over eating. HF HRV could be a potential biomarker for food craving and food-related self-regulation capacity, and therefore may aid weight management interventions.

546-P: Effects of Metformin on Heart Rate Variability in Adolescents with Type 1 Diabetes: A Secondary Analysis of a Randomized Crossover-Controlled Trial

Aims: Metformin might improve glycemic control in patients with T1D, but whether it has cardiovascular benefit is controversial. We aimed to investigate whether metformin improved cardiac autonomic neuropathy, as measured by heart rate variability (HRV), in patients with T1D. Methods: This is a secondary analysis of a crossover, randomized trial conducted in adolescents with T1D inadequately controlled with insulin. Patients were randomly received metformin added on insulin for 24 weeks followed by insulin treatment alone for a subsequent 24 weeks or vice versa. The mean amplitude of glycemic excursions (MAGE) was obtained from CGM as a measure of glucose variability, while SD of beat-to-beat (NN) intervals (SDNN), SD of the average NN intervals calculated over 5 minutes (SDANN), the percentage of the interval differences of successive NN intervals greater than 50 ms (PNN50), the square root of the mean squared differences of successive NN intervals (RMSSD), low-frequency (LF) and high frequency (HF) power were assessed by 24-h Holter monitoring as measures of HRV. Results: Seventeen patients with age 14.4±2.3 years, BMI 18.2±1.8 kg/m2, T1D duration 5.4±3.2 years and HbA1c 9.2±1.6% were enrolled. Changes in HbA1c, BMI, lipid profiles and MAGE were similar between groups. Compared with insulin monotherapy, metformin added on insulin markedly increased SDNN (between group difference [SE], 26.96 [11.77], P=0.034), SDANN (25.62 [12.12], P= 0.049), pNN50 (10.14 [3.05], P= 0.003) and HF (236.08 [83.21], P= 0.01). Changes in RMSSD and LF were not different between groups. In a multivariable regression analysis, the increase in SDNN remained significant after adjusting for ΔHbA1c, ΔMAGE and Δ systolic blood pressure (SBP) (β= 28.62, P= 0.039), suggesting the independent effect of metformin on SDNN. Conclusions: In adolescent patients with T1D, metformin increased HRV despite no obvious effect on improvement in metabolic parameters. Disclosure D. Yang: None. W. Xu: None. H. Deng: None. J. Lv: None. J. Yan: None. B. Yao: None. J. Weng: None. Funding National Key Research and Development Program of China (2017YFC1309602); Science and Technology Planning Project of Guangdong Province (2017A020215142); Natural Science Foundation of Guangdong Province (2019A1515010979)

Sexual Dimorphism of Heart Rate Variability in Adolescence: A Case-Control Study on Depression, Anxiety, Stress Levels, Body Composition, and Heart Rate Variability in Adolescents with Impaired Fasting Glucose.

Prediabetes in the form of impaired fasting glucose, impaired glucose tolerance, or both is considered as a preliminary stage for the onset of diabetes and diabetic complications. Hormonal fluctuations in adolescence are accompanied by body composition modifications, which are associated with insulin resistance and subclinical inflammation. Bioimpedance (BIA) accurately evaluates body composition, and heart rate variability (HRV) assesses cardiac autonomic function, which are frequently afflicted by insulin resistance. We aimed at evaluating the effect of glycemic status on mental stress, anxiety, and depression status in adolescents with impaired fasting glucose, body composition, and HRV parameters. This is a case-control study to evaluate the effect of the hyperglycemia on depression, anxiety, and stress levels (DASS21 questionnaire), body composition (BIA-ACC—BIOTEKNA©), and HRV (PPG Stress Flow—BIOTEKNA©), between euglycemic adolescents (euglycemic group) and adolescents with impaired fasting glucose (prediabetic group), aged 12–20 years. No differences were found between the prediabetic (n = 13) and the euglycemic (n = 16) groups in the outcome measures, possibly due to the number of participants. Interestingly, females, irrespective of their glycemic status, exhibited altered sympathovagal function as revealed by impaired HRV. In the euglycemic group, HRV parameters were significantly correlated and in line with the DASS21 scores, but in the prediabetic group, similarities to those of adults were observed. Impaired fasting glucose had no impact on mental health, body composition, or HRV parameters in adolescents. HRV parameters were impaired in females, irrespective of their glycemic status. This finding implies that females seem to be more prone to stress disorders, even from a young age. Future studies are needed to confirm these findings.

Характеристика вариабельности сердечного ритма у подростков-северян, употребляющих летучие растворители

Характеристика вариабельности сердечного ритма у подростков-северян, употребляющих летучие растворители

Association between snoring and heart rate variability in adolescents: effects of gender and insufficient sleep.

We explored the association between subjective snoring frequency and heart rate variability (HRV) in a healthy adolescent population. A total of 102 healthy adolescents were recruited from high schools in South Korea, and reported their sleep habits and snoring frequency. HRV was assessed to indirectly measure autonomic function. We assessed correlations between snoring frequency and HRV indices. We also investigated the effects of sex and behaviorally induced insufficient sleep syndrome (BISS) on the associations between HRV parameters and snoring frequency. Overall, significant correlations were apparent between snoring frequency and HRV indices including the standard deviation of the normal-to-normal intervals (SDNN) and the low-frequency/high-frequency (LF/HF) ratio. Associations were more evident in males and those with BISS compared to females and those without BISS. Our findings suggest that snoring changes autonomic nervous system (ANS) activity in adolescents; the changes are more dramatic in males and those with insufficient sleep.

Association between reaction time and heart rate variability in adolescents with cardiovascular risk

Background: In obesity and/or family history of hypertension (HT) or diabetes mellitus (DM), there is a higher prevalence of cardiovascular (CV) disease in the subject, which is supposed to be due to autonomic imbalance. The alterations in cardiac autonomic functions can be assessed by heart rate variability (HRV) indicators and there is a relationship between HRV and reaction time (RT) also. Aims and Objectives: This study aims to assess the HRV and RT in adolescents with CV risk and also to find the association between these two parameters. Materials and Methods: A total of 39 adolescents with CV risk (15 females and 24 males) in the age group of 14–15 years who were obese or/and had family history of HT or DM in parents were selected. Anthropometric parameters, blood pressure, HRV parameters, and RT were recorded. Results: HRV was reduced in CV risk groups, both in females and males as compared to normal subjects and lower values were recorded in females as compared to males. There was also a negative correlation of HRV with RT both in males and females but statistically significant only in females. Conclusion: Adolescents with CV risk have reduced HRV and such individuals are more prone to CV diseases. RT, which is a marker of cognitive ability, is increased in persons with decreased HRV, and hence, such CV risk adolescents should be followed up and given timely intervention.

Altered Heart Rate Regulation in Adolescent Girls and the Vulnerability for Internalizing Disorders.

Background: The association between decreased heart rate variability (HRV) and increased internalizing symptoms is well documented. Adolescence is a critical period for the development of mental health problems, in particular internalizing symptoms. Previous research has illustrated sex differences in adolescent HRV, such that females have reduced short-term resting state HRV compared to males. Studies on long-term ecological recordings of HRV in adolescents are scarce. The aims of the present study were, (a) to test if adolescent females show decreased long-term HRV and cardiac complexity (CC) compared to males, and (b) to explore whether sex and HRV and CC measures, as well as their interaction, would predict internalizing symptoms.Materials and Methods: HRV was recorded in n = 166 adolescents (86 girls), on a normal school day. HRV and CC measures were calculated on the interbeat interval time series.Results: Females showed lower HRV and CC in most of the assessed indices. Internalizing symptoms were mainly predicted by HRV whereas sex only predicted symptoms of social anxiety. The interaction between sex and HRV did not predict internalizing symptoms.Conclusions: Results suggest that reduced HRV should be considered as a potential contributor to exacerbating internalizing symptoms in adolescence. Girls with reduced HRV and CC might be prone to the development of internalizing disorders. HRV is a promising tool for the early identification of vulnerability.

Sleep Quality and Heart Rate Variability in Adolescents with Type 1 or Type 2 Diabetes

Regardless of the type of diabetes, there is twice the risk of experiencing cardiovascular (CV) disease complications in comparison to not having the disease. Although these complications and associated symptoms are rarely noted in adolescents with diabetes, early identification of biobehavioral markers for CV risks are essential for targeted approaches for prevention of later disease sequelae. Decreased sleep quality and heart rate variability (HRV) have both independently been associated with diabetes or the presence of obesity and risk for developing diabetes, as well as with CV disease. Studies exploring both sleep quality and HRV in adolescents with diabetes are not available. Thus, we conducted a secondary analysis of data from an existing study to examine differences in sleep quality and HRV in adolescents with type 1 (T1D) vs. type 2 diabetes (T2D); and to determine if there were associations between HRV and sleep quality. Adolescents with T1D (n = 101; 56 males) or T2D (n= 37; 16 males) completed 24-hour HRV Holter monitoring and measurement using Burdick Vision Premier™ ECG Analysis and Editing software system (Waukesha, WI), hemoglobin A1c (HbA1c) using the Abbott IMx® assay method, and a self-report global measure of the impact of diabetes on their sleep quality using a 5-point Likert scale. Duration of diabetes was greater (P \ .001) and measures of HRV were higher in T1D (P \ .01); BMI and BMI z-scores (P \ .001) and systolic and diastolic BP (P ≤ .05) were higher in T2D. No differences in recent or average HbA1c, Tanner staging or sleep quality were found. Both spectral and time domain measures of HRV were associated with sleep quality in T2D (r = - .51 to -.38, P \ .02); only time domain measures were associated with sleep quality in T1D (r = -. 21 to -.19, P ≤ .05). Poorer sleep quality was evident in those with lower HRV; these linkages were stronger in those with T2D. Further study is warranted to elucidate risks and improve sleep quality and CV outcomes in youth with diabetes. Disclosure M.S. Faulkner: None. A. Helvig: None.