Markers of stress and inflammation as potential mediators of the relationship between exercise and depressive symptoms: findings from the TRAILS study

Mechanisms Linking Physical Activity with Psychiatric Symptoms Across the Lifespan: A Systematic Review

BACKGROUND

Physical activity has been suggested as a protective factor against psychiatric symptoms. While numerous studies have focused on the magnitude of physical activity's effect on psychiatric symptoms, few have examined the potential mechanisms.

OBJECTIVE

The current review aimed to synthesize scientific evidence of the mechanisms through which physical activity might reduce psychiatric symptoms across the lifespan.

METHODS

We included articles that were published before March 2022 from five electronic databases (MEDLINE, Web of Science, PsycINFO, Embase, and Cochrane). A qualitative synthesis of studies was conducted. The risk of bias assessment was performed using The Joanna Briggs Institute Critical Appraisal Tool for Systematic Reviews. Studies were included if they explored the possible mechanisms through which physical activity influences psychiatric symptoms (i.e., internalizing and externalizing symptoms) across the lifespan.

RESULTS

A total of 22 articles were included (three randomized controlled trials, four non-randomized controlled trials, three prospective longitudinal studies, and 12 cross-sectional studies). Overall, most of the studies focused on children, adolescents, and young adults. Our findings showed that self-esteem, self-concept, and self-efficacy were the only consistent paths through which physical activity influences psychiatric symptoms (specifically depressive and anxiety symptoms) across the lifespan. There were insufficient studies to determine the role of neurobiological mechanisms.

CONCLUSIONS

Overall, future physical activity interventions with the purpose of improving mental health should consider these mechanisms (self-esteem, self-concept, self-efficacy) to develop more effective interventions.

CLINICAL TRIAL REGISTRATION

The protocol of this study was registered in the PROSPERO database (registration number CRD42021239440) and published in April 2022.

The association between recreational physical activity and depression in the short sleep population: a cross-sectional study

Background

Short sleep is more common in the modern society. Recreational physical activity (RPA) like exercise brings both mental and physiological benefits to depression; paradoxically, lack of sleep is harmful. Evidence on the association between RPA and depression in the short sleep population is limited.

Methods

Participants with short sleep condition from the National health and Nutrition Examination Surveys (NHANES 2007-2018) were included in the present study. Short sleep condition was defined as ≤ 7 h per night. Sleep duration and RPA status were self-reported in NHANES by the Physical Activity Questionnaire using a 7-day recall method. Multivariable logistic regression was applied to evaluate the association between RPA and depression. Additionally, the non-linear relationship between RPA and depression was evaluated using the threshold effect analysis and restricted cubic spline.

Results

This cross-sectional study comprised 6,846 adults' data, and the weighted participants were 52,501,159. The weighted prevalence of depression was higher in females, which took up 65.85% of all depression patients. In fully adjusted models, sufficient volume of RPA was associated with lower depression risks, with OR (95% CI) =0.678 (0.520, 0.883). Further analysis revealed a U-shaped association between RPA and incident depression, and the inflection point was 640 MET-minutes/week. When RPA <640 MET-minutes/week, increased RPA was associated with lower risk of incident depression, with OR (95% CI) = 0.891 (0.834, 0.953). When RPA ≥ 640 MET-minutes/week, the benefits of RPA seemed to be not significant, with OR (95% CI) = 0.999 (0.990, 1.009).

Conclusion

Our findings observed associations between RPA condition and incident depression in the short sleep population. Moderate RPA was beneficial to maintain mental health and associated with lower incidence of depression for short sleepers, but excessive RPA might increase the risk of depression. For general short sleepers, keeping the RPA volume approximately 640 MET-minutes/week was beneficial to lower risks of depression. Gender difference should be considered as an important factor for further studies to examine these relationships and explore mechanisms.

The effect of using activity workstations on heart rate variability during complex cognitive tasks

ObjectivesThe purpose of the current study was to examine the effects of using an activity workstation on the physiological stress response as measured by heart rate variability while completing cognitively demanding tasks. Participants: Eleven college students (6 females; age: 19.4 ± 0.9 years) participated in the study. Methods: The participants completed three psychologically stressful cognitive tasks while seated at a traditional desk and while using an activity workstation. Heart rate variability was recorded and analyzed with power spectrum density and time-domain analysis. Results: Using activity workstations while completing stressful cognitive tasks did not negatively affect task performance. There was; however, a reduction in low frequency heart rate variability but no change in cardiac sympathovagal balance. Conclusion: The results indicate that using activity workstations while completing difficult tasks reduces sympathetic reactivity to stress in college students. This suggests that using activity workstations could provide a coping mechanism for stress.

Inflammation and depression in young people: a systematic review and proposed inflammatory pathways

Depression onset peaks during adolescence and young adulthood. Current treatments are only moderately effective, driving the search for novel pathophysiological mechanisms underlying youth depression. Inflammatory dysregulation has been shown in adults with depression, however, less is known about inflammation in youth depression. This systematic review identified 109 studies examining the association between inflammation and youth depression and showed subtle evidence for inflammatory dysregulation in youth depression. Longitudinal studies support the bidirectional association between inflammation and depression in youth. We hypothesise multiple inflammatory pathways contributing to depression. More research is needed on anti-inflammatory treatments, potentially tailored to individual symptom profiles.

Hippocampal Acetylation may Improve Prenatal-Stress-Induced Depression-Like Behavior of Male Offspring Rats Through Regulating AMPARs Expression

This study is to determine the role and mechanism of hippocampal acetylation in prenatal stress (PS) induced depression-like behavior of male offspring rats. PS-induced depression rat model was established. Sucrose preference and forced swim test were used to observe the behavior changes of male offspring rats. Hippocampal acetylation was induced by Trichostatin A injection. Quantitative real-time PCR and Western blot were used to determine the changes of AMPARs in acetylated hippocampus. The behavioral tests proved that AMPA was involved in the PS-induced depression-like behavior in offspring rats. Hippocampal acetylation significantly increased the preference to sucrose of PS-induced offspring rats and reduced the immobile time in forced swimming test, suggesting that acetylation could improve PS-induced depression-like behaviors. In addition, PS inhibited the expression levels of GluA1-3 subunits of AMPARs in the offspring hippocampus, while Hippocampal acetylation could reverse this effect by increasing GluA1-3 expression. PS-induced reduction of GluA1-3 subunits of AMPARs may be an important potential mechanism of offspring depression. Hippocampal acetylation may improve PS-induced offspring depression-like behavior through the enhanced expression of AMPARs (GluA1-3 subunits).

Sudarshan Kriya Yoga improves cardiac autonomic control in patients with anxiety-depression disorders

BACKGROUND

Several studies have demonstrated that adjuvant therapies as exercise and breathing training are effective in improving cardiac autonomic control (CAC) in patients with affective spectrum disorders. However, the effects of Sudarshan Kriya Yoga (SKY) on autonomic function in this population is unknown. Our objective was to test the hypothesis that SKY training improves CAC and cardiorespiratory coupling in patients with anxiety and/or depression disorders.

METHODS

Forty-six patients with a diagnosis of anxiety and/or depression disorders (DSM-IV) were consecutively enrolled and divided in two groups: 1) conventional therapy (Control) and 2) conventional therapy associated with SKY (Treatment) for 15 days. Anxiety and depression levels were determined using quantitative questionnaires. For the assessment of CAC and cardiorespiratory coupling, cardiorespiratory traces were analyzed using monovariate and bivariate autoregressive spectral analysis, respectively.

RESULTS

After 15-days, we observed a reduction of anxiety and depression levels only in Treatment group. Moreover, sympathetic modulation and CAC were significantly lower while parasympathetic modulation and cardiorespiratory coupling were significantly higher in the Treatment compared to Control group.

CONCLUSIONS

Intensive breathing training using SKY approach improves anxiety and/or depressive disorders as well as CAC and cardiorespiratory coupling. These finding suggest that the SKY training may be a useful non-pharmacological intervention to improve symptoms and reduce cardiovascular risk in patients with anxiety/depression disorders.

Inter-individual differences in the experience of negative emotion predict variations in functional brain architecture

Current evidence suggests that two spatially distinct neuroanatomical networks, the dorsal attention network (DAN) and the default mode network (DMN), support externally and internally oriented cognition, respectively, and are functionally regulated by a third, frontoparietal control network (FPC). Interactions among these networks contribute to normal variations in cognitive functioning and to the aberrant affective profiles present in certain clinical conditions, such as major depression. Nevertheless, their links to non-clinical variations in affective functioning are still poorly understood. To address this issue, we used fMRI to measure the intrinsic functional interactions among these networks in a sample of predominantly younger women (N=162) from the Human Connectome Project. Consistent with the previously documented dichotomous motivational orientations (i.e., withdrawal versus approach) associated with sadness versus anger, we hypothesized that greater sadness would predict greater DMN (rather than DAN) functional dominance, whereas greater anger would predict the opposite. Overall, there was evidence of greater DAN (rather than DMN) functional dominance, but this pattern was modulated by current experience of specific negative emotions, as well as subclinical depressive and anxiety symptoms. Thus, greater levels of currently experienced sadness and subclinical depression independently predicted weaker DAN functional dominance (i.e., weaker DAN-FPC functional connectivity), likely reflecting reduced goal-directed attention towards the external perceptual environment. Complementarily, greater levels of currently experienced anger and subclinical anxiety predicted greater DAN functional dominance (i.e., greater DAN-FPC functional connectivity and, for anxiety only, also weaker DMN-FPC coupling). Our findings suggest that distinct affective states and subclinical mood symptoms have dissociable neural signatures, reflective of the symbiotic relationship between cognitive processes and emotional states.

Gene-environment interaction in major depression: focus on experience-dependent biological systems

Major depressive disorder (MDD) is a multifactorial and polygenic disorder, where multiple and partially overlapping sets of susceptibility genes interact each other and with the environment, predisposing individuals to the development of the illness. Thus, MDD results from a complex interplay of vulnerability genes and environmental factors that act cumulatively throughout individual's lifetime. Among these environmental factors, stressful life experiences, especially those occurring early in life, have been suggested to exert a crucial impact on brain development, leading to permanent functional changes that may contribute to lifelong risk for mental health outcomes. In this review, we will discuss how genetic variants (polymorphisms, SNPs) within genes operating in neurobiological systems that mediate stress response and synaptic plasticity, can impact, by themselves, the vulnerability risk for MDD; we will also consider how this MDD risk can be further modulated when gene × environment interaction is taken into account. Finally, we will discuss the role of epigenetic mechanisms, and in particular of DNA methylation and miRNAs expression changes, in mediating the effect of the stress on the vulnerability risk to develop MDD. Taken together, we aim to underlie the role of genetic and epigenetic processes involved in stress- and neuroplasticity-related biological systems on the development of MDD after exposure to early life stress, thereby building the basis for future research and clinical interventions.