The utility of combining respiratory sinus arrhythmia indices in association with internet addiction

The moderating effect of resting heart rate variability on the relationship between internet addiction tendency and brain morphology

Previous neuroimaging studies have investigated brain morphology associated with internet addiction tendency (IAT) in healthy subjects. However, whether resting vagally-mediated heart rate variability (HRV) exerting influences on the association of IAT and brain morphology remains unclear. This study used voxel-based morphometry (VBM) and multiple regression analyses to assess the interaction effect of IAT and resting vagally-mediated HRV on regional grey matter volumes in 82 healthy subjects. To further illustrate the observed interaction effect, the moderated hierarchical regression analysis was performed. The results showed that resting vagally-mediated HRV moderated the relationship between IAT scores and grey matter volume (GMV) in the precuneus and cerebellum. Specifically, individuals with higher resting vagally-mediated HRV showed a significant positive relationship between IAT scores and GMV in the precuneus, whereas individuals with lower resting vagally-mediated HRV showed a significant negative relationship between IAT scores and GMV in the precuneus. In addition, IAT scores were negatively correlated with GMV in the cerebellum among individuals with lower resting vagally-mediated HRV, but not among individuals with higher resting vagally-mediated HRV. These findings have demonstrated a moderating role of resting vagally-mediated HRV on the association of IAT and brain morphology.

Interactive effects of childhood maltreatment and tonic respiratory sinus arrhythmia on young adults' depressive symptoms

The goal of the current study was to investigate the moderating effect of tonic respiratory sinus arrhythmia (RSA) in the relation between childhood maltreatment and depression symptoms among young adults. A total of 98 participants (70 women) aged 17-22 years completed questionnaires on childhood maltreatment and depressive symptoms. RSA data were obtained during a resting condition in the laboratory. Results indicated that childhood maltreatment interacted with tonic RSA to predict depressive symptoms, even after controlling for age and body mass index (BMI) of each participant. Specifically, higher levels of childhood maltreatment were associated with higher levels of depressive symptoms, but only among young adults who exhibited lower tonic RSA. The results indicated that the association between childhood maltreatment and depressive symptoms depends on young adults' physiological functioning/flexibility. Findings suggest that consideration of external environmental factors in combination with internal physiological factors is critical to understand young adults' mental health.

Cardiovascular response to physical exercise and the risk of Internet addiction in 15-16-year-old adolescents

BACKGROUND AND AIM

Subjective symptoms of Internet addiction (IA), such as interpersonal and health-related problems (IH-RP), do not correlate with objective physiological parameters. This study aimed to investigate the cardiovascular reactivity after physical exercise in 15-16-year-old adolescents showing different severities of symptoms of health-related problems due to Internet overuse.

METHODS

This study included 20 healthy adolescents (boys, 15-16 years) with different risks of IA (by the Chen internet addiction scale [CIAS]). The physical exercise test was to perform a standing broad jump three times. The arterial blood pressures and heart rates were recorded before, immediately after, and at 4 minutes of rest after exercise.

RESULTS AND DISCUSSION

The total sample of adolescents was divided into two groups, that is, those with IH-RP scores of 12 or less (Group I, n = 12) and those scoring more than 12 points (Group II, n = 8). The diastolic blood pressure significantly increased after exercise in group II, whereas it remained stable in group I. The heart rate in group I tended to increase, but the changes were not statistically significant. Group II adolescents showed significant increases in heart rate, and at rest, this parameter was significantly higher than the baseline value.

CONCLUSIONS

Adolescents with a risk of IA and severe symptoms of interpersonal and health-related problems had increased sympathetic activity during and after speed-strength physical exercise compared to those without the aforementioned symptoms.