Exercise reveals the interrelation of physical fitness, inflammatory response, psychopathology, and autonomic function in patients with schizophrenia

From brain to body: exploring the connection between altered reward processing and physical fitness in schizophrenia

Understanding the underlying mechanisms that link psychopathology and physical comorbidities in schizophrenia is crucial since decreased physical fitness and overweight pose major risk factors for cardio-vascular diseases and decrease the patients' life expectancies. We hypothesize that altered reward anticipation plays an important role in this. We implemented the Monetary Incentive Delay task in a MR scanner and a fitness test battery to compare schizophrenia patients (SZ, n = 43) with sex- and age-matched healthy controls (HC, n = 36) as to reward processing and their physical fitness. We found differences in reward anticipation between SZs and HCs, whereby increased activity in HCs positively correlated with overall physical condition and negatively correlated with psychopathology. On the other handy, SZs revealed stronger activity in the posterior cingulate cortex and in cerebellar regions during reward anticipation, which could be linked to decreased overall physical fitness. These findings demonstrate that a dysregulated reward system is not only responsible for the symptomatology of schizophrenia, but might also be involved in physical comorbidities which could pave the way for future lifestyle therapy interventions.

Systematic Review and Meta-analysis of Exercise Interventions for Psychotic Disorders: The Impact of Exercise Intensity, Mindfulness Components, and Other Moderators on Symptoms, Functioning, and Cardiometabolic Health

BACKGROUND AND HYPOTHESIS

Exercise therapy has been shown to be an effective complementary treatment for patients with psychotic disorders. However, the specific impacts of different training modalities remain poorly understood. This article aims to quantitatively review the moderating influence of different exercise modalities, hypothesizing that higher exercise intensity as well as utilization of mindfulness-based exercise (MBE) components, will improve intervention outcomes.

STUDY DESIGN

PubMed, Web of Science, and PsycINFO were searched from 2010 to March 2022 for randomized controlled trials investigating exercise interventions in patients with psychotic disorders (preregistration: https://doi.org/10.17605/OSF.IO/J8QNS). Outcomes considered were positive/negative symptoms, Positive and Negative Syndrome Scale (PANSS) General Psychopathology/Total scores, depressive symptoms, psychosocial functioning, quality of life, cardiorespiratory fitness, and body mass index. Separate meta-analyses, including moderator analyses, were performed to evaluate the moderating influence of different training modalities.

STUDY RESULTS

Of 6653 studies, 40 (n = 2111 patients) were included in the meta-analysis. The effects of moderate-intensity exercise exceed low-intensity approaches for PANSS Total scores (P = .02) and depressive symptoms (P = .04). The presence of MBE components was associated with improvements in positive symptoms (P = .04) and PANSS General Psychopathology subscores (P = .04) but also with higher error and between-study heterogeneity. Our analysis also shows improved intervention effects on depression in younger patients (P = .012) and improved psychosocial functioning scores following more frequent sessions (P < .01).

CONCLUSIONS

A minimum of moderate intensity should be considered. More frequent training sessions per week also seem to be beneficial. While adding mindfulness elements is promising, it increases heterogeneity and requires caution in terms of generalization.

Lactate levels in the brain and blood of schizophrenia patients: A systematic review and meta-analysis

BACKGROUND

The pathophysiological mechanisms of schizophrenia are still unclear. Converging evidence suggests that energy metabolism abnormalities are involved in schizophrenia, and support its role in the pathophysiology of this disease. Lactate plays an important role in energy metabolism. Many studies have reported changes in the levels of lactate in the brain and serum of schizophrenia patients; however, the results from these studies are not consistent. To overcome this limitation, the goal of the present meta-analysis is to analyze the changes in lactate levels in the brain and blood of schizophrenia patients.

METHODS

For this systematic review and meta-analysis, we performed a thorough search of relevant literature in the English language, using the MEDLINE, Cochrane, and Embase databases.

RESULTS

In the present meta-analysis, 20 studies were scrutinized, including 13 studies on brain lactate levels, which involved 322 schizophrenia patients and 324 healthy individuals as controls. 7 studies on blood lactate levels, involving 234 schizophrenia patients and 238 healthy individuals, were also included. Brain lactate levels were elevated in schizophrenia patients, both in vivo and in post-mortem studies. Nevertheless, blood lactate levels in schizophrenia patients have revealed no statistically significant difference, as compared with control individuals.

CONCLUSIONS

In comparison with healthy individuals, schizophrenia patients had higher lactate levels in the brain, rather than in the blood. These findings suggest independent regulatory mechanisms of lactate levels in the brain and peripheral tissues. Abnormal lactate metabolism in the brain may be an important pathological mechanism in schizophrenia.

Alterations in inflammatory markers after a 12-week exercise program in individuals with schizophrenia-a randomized controlled trial

Background

In individuals with schizophrenia, inflammation is associated with depression, somatic comorbidity and reduced quality of life. Physical exercise is known to reduce inflammation in other populations, but we have only limited knowledge in the field of schizophrenia. We assessed inflammatory markers in plasma samples from individuals with schizophrenia participating in an exercise intervention randomized controlled trial. We hypothesized that (i) physical exercise would reduce levels of inflammatory markers and (ii) elevated inflammatory status at baseline would be associated with improvement in cardiorespiratory fitness (CRF) following intervention.

Method

Eighty-two individuals with schizophrenia were randomized to a 12-week intervention of either high-intensity interval training (HIIT, n = 43) or active video gaming (AVG, n = 39). Participants were assessed at baseline, post intervention and four months later. The associations between exercise and the inflammatory markers soluble urokinase plasminogen activator receptor, c-reactive protein, tumor necrosis factor (TNF), soluble TNF receptor 1 and interleukin 6 (IL-6) were estimated using linear mixed effect models for repeated measures. For estimating associations between baseline inflammation and change in CRF, we used linear regression models.

Results

Our main findings were (i) TNF and IL-6 increased during the intervention period for both groups. Other inflammatory markers did not change during the exercise intervention period; (ii) baseline inflammatory status did not influence change in CRF during intervention, except for a positive association between baseline IL-6 levels and improvements of CRF to post intervention for both groups.

Conclusion

In our study, HIIT and AVG for 12-weeks had no reducing effect on inflammatory markers. Patients with high baseline IL-6 levels had a positive change in CRF during intervention. In order to increase our knowledge regarding association between inflammatory markers and exercise in individuals with schizophrenia, larger studies with more frequent and longer exercise bout duration are warranted.

Changes in inflammation are related to depression and amount of aerobic exercise in first episode schizophrenia

INTRODUCTION

Elevated levels of pro-inflammatory cytokines have been reported in meta-analyses of multi-episode schizophrenia patients when compared to controls. However, little is known about whether these same relationships are present in the early course of schizophrenia.

OBJECTIVE

To assess first episode schizophrenia patients for depression and to assay blood samples collected at baseline and at 6 months for interleukin-6 (IL-6).

MATERIALS AND METHODS

Trained raters used the Brief Psychiatric Rating Scale to assess depressive symptoms and a standard lab assay kit to assess for IL-6 levels in plasma.

CONCLUSIONS

Decreases in pro-inflammatory IL-6 levels were significantly related to decreases in depressive symptoms. Within a subset of patients in a 6-month aerobic exercise protocol, the number of exercise sessions completed was significantly correlated with the amount of decrease in IL-6. The reductions observed in IL-6 with aerobic exercise suggest exercise is a promising intervention to reduce brain inflammation effects in schizophrenia patients.

Different serum protein factor levels in first-episode drug-naive patients with schizophrenia characterized by positive and negative symptoms

AIM

The clinical features of schizophrenia can be mainly divided into two symptom domains: positive and negative. Patients in each symptom domain respond differently to treatments, and their prognoses vary accordingly. Serum protein factors, such as nerve growth factor (NGF), neurotrophin-3 (NT-3), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and the calcium-binding protein, S100β, have been reported to be involved in the pathogenesis of schizophrenia. However, their roles in the positive and negative symptom domains have not been determined. In this study, we investigated whether the serum levels of these five protein factors differed among first-episode drug-naive schizophrenia patients in each symptom domain and in healthy controls.

METHODS

Double-antibody sandwich ELISA were used to quantify the amounts of the five protein factors in serum.

RESULTS

Compared with the levels in the controls (n = 60), increased serum levels of IL-6, IL-1β, and S100β and decreased serum levels of NGF and NT-3 were observed in first-episode drug-naive schizophrenia patients. Additionally, the serum levels of IL-6 and IL-1β were significantly higher in schizophrenia patients characterized by negative symptoms (negative group, n = 37) than in those characterized by positive symptoms (positive group, n = 46). Based on multivariate regression analyses, serum levels of IL-1β were positively associated with the Negative Symptom subscore of the Positive and Negative Syndrome Scale in the negative group and in all patients with schizophrenia.

CONCLUSION

The two subtypes of schizophrenia may have different pathological mechanisms. Patients characterized by negative symptoms probably have more serious disturbances in neuroimmunology.

Effect of high-intensity interval training on cardiorespiratory fitness, physical activity and body composition in people with schizophrenia: a randomized controlled trial

BACKGROUND

Exercise may improve cardiorespiratory fitness in people with schizophrenia, however, possible condition-specific cardiorespiratory disadvantages, a scarcity of methodologically sound studies, and conflicting results raise questions about the effect of exercise on maximal oxygen uptake (VO_2max) in this group. The primary aim of this study, therefore, was to investigate the effect of high-intensity interval training on VO_2max in people with schizophrenia. Second, we sought to determine whether the intervention would have an effect on general physical activity (PA) level and body composition.

METHODS

Eighty-two patients with schizophrenia were randomly assigned to supervised high-intensity interval training or computer gaming skills training, performed twice a week for 12 weeks. Oxygen uptake was measured directly, during a maximum exercise session on a treadmill. PA level were assessed using ActiGraph accelerometer, and body composition was assessed by bioelectrical impedance. Differences between groups were assessed by analysis of variance using a univariate general linear model.

RESULTS

There were no significant differences between the groups on any of the cardiorespiratory variables neither at baseline nor after the program. There were also no significant within-group differences in any of the cardiorespiratory fitness variables between the baseline and post-program time points, despite that 61% of the participants performing high-intensity interval training showed a significant increase in workload on the treadmill. However, 47% of the participants in the high-intensity interval training group had a ≥ 5% increase in VO_2max. Participants supervised by mental health care providers with PA competence (e.g. rehabilitation center staff, sport scientist, physical trainer) had a much larger increase in VO_2max compared to participants supervised by mental health workers without such competence, and when adding PA competence to the model, the intervention group increased VO_2max significantly compared to the comparison group. The intervention had no significant effect on PA level or body composition.

CONCLUSIONS

The intervention did not improve VO_2max, PA level or body composition but succeeded in increasing workload on the treadmill. With regard to VO_2max, approximately half of the patients may be considered responders.

TRIAL REGISTRATION

ClinicalTrials.gov ; NCT02205684 , registered July 2014.

Is there an association between cardiorespiratory fitness and stage of illness in psychotic disorders? A systematic review and meta-analysis

BACKGROUND

Clinical staging models describe where an individual exists on a continuum from asymptomatic at-risk states (Stage 0) through to established late-stage disease (Stage 4). We applied this framework to systematically assess evidence for any associations between objectively assessed cardiorespiratory fitness (CRF) and stage of psychosis.

METHOD

Nine electronic databases were searched for relevant publications from inception until October 31, 2019. Pooled effect sizes (Hedges' g and 95% confidence intervals (95% CI)) were estimated for differences in CRF for studies that reported mean oxygen uptake (max, peak, or predicted VO₂ in ml/kg/min).

RESULTS

Thirty-eight studies were eligible. Findings indicated that suboptimal CRF can be present at Stages 0 and 1. Meta-analyses of 22 studies demonstrated that CRF was significantly reduced in individuals classified between Stages 1 and 4 compared with matched or general population controls (g = -0.93; 95% CI -1.14, -0.71). Mean VO₂ was decreased by 28% in Stage 4 compared with Stage 1 (34.1 vs. 24.66 ml/kg/min); the largest effect size for CRF reduction was reported between Stages 2 and 3 (g = -1.16; 95% CI -1.31, -1.03).

CONCLUSIONS

Although not identifying direct causal links between clinical stage and CRF, using this framework may enhance understanding of co-associations between mental and physical health markers across the entire spectrum of psychosis. Limitations include lack of research on CRF in Stages 0 and 1 alongside problems determining stage in some studies. However, impaired CRF is reported in emerging psychosis, supporting calls that early intervention programmes should address both mental and physical wellbeing.

Meta-analysis of physical activity and effects of social function and quality of life on the physical activity in patients with schizophrenia

Schizophrenia patients have increased mortality and morbidity, mainly due to premature cardiovascular disease resulting from decreased physical activity (PA). However, which PA intensity is impaired in the patients and how factors such as social function and quality of life (QoL) are related to decreased PA is unknown. To assess PA, social function and QoL, the International Physical Activity Questionnaire (IPAQ), Social Functioning Scale (SFS) and Schizophrenia Quality of Life Scale (SQLS), respectively, were used in 109 schizophrenia patients and 69 healthy subjects. A meta-analysis comparing PA intensities (vigorous, moderate and light) assessed by the single PA measurement between schizophrenia patients and healthy subjects after including our case-control sample was performed. Furthermore, the effects of social function and QoL on each level of PA intensity were investigated in patients and controls. The meta-analysis in 212 schizophrenia patients and 132 healthy subjects revealed that patients showed lower total PA, particularly vigorous PA, than controls (I² = 0, Hedges' g = - 0.41, P = 2.80 × 10^-4). The decreased total PA was correlated with impaired total SFS scores (β = 0.24, P = 2.86 × 10^-3), withdrawal (β = 0.23, P = 3.74 × 10^-3) and recreation (β = 0.23, P = 3.49 × 10^-3) without significant heterogeneity between patients and controls. In contrast, the decreased total PA was affected by low independence-performance (β = 0.22, P = 0.034), employment/occupation (β = 0.27, P = 8.74 × 10^-3), psychosocial (β = - 0.24, P = 0.021) and motivation/energy (β = - 0.26, P = 0.013), but only in patients. Similar findings were obtained for vigorous PA but not moderate or light PA. Our findings suggest that the impaired vigorous PA in schizophrenia patients may be mediated by schizophrenia-specific factors of social functioning and QoL. Understanding these factors has important implications for increasing PA participation in schizophrenia patients.

Physical fitness and physical activity levels in people with alcohol use disorder versus matched healthy controls: A pilot study

Low physical fitness and physical inactivity have been recognized as prominent behavioral risk factors for cardiovascular diseases and an independent risk factor for all-cause mortality. To date, no studies have ystematically assessed physical fitness and physical activity in patients with alcohol use disorders (AUD) vs. a healthy comparison group. The aim of this cross-sectional study was to assess and compare the physical fitness and physical activity levels in patients with AUD against healthy controls. Thirty inpatients with AUD (22 males, 40.4 ± 10.5 years, illness duration = 9.7 ± 9.3 years) and 30 age-, gender- and body mass index (BMI)-matched healthy controls were included. All participants performed the Eurofit test battery and the International Physical Activity Questionnaire. Patients also completed the Positive Affect and Negative Affect Scale (PANAS) and Alcohol Use Disorders Identification Test (AUDIT). The PANAS positive and negative scores were 30.1 ± 7.5 and 27.6 ± 8.2; the AUDIT score was 27.3 ± 7.0. Patients with AUD had a reduced whole body balance (flamingo balance test: 12.1 ± 5.1 vs. 8.7 ± 3.9 attempts; p = 0.005), speed of limb movement (plate tapping: 13.3 ± 2.7 vs. 11.6 ± 2.2 s, p = 0.007), explosive leg muscle strength (standing broad jump: 151.8 ± 34.9 vs. 174.2 ± 33.7 cm; p = 0.01), abdominal muscular endurance (sit-ups: 15.9 ± 5.7 vs. 19.8 ± 7.1; p = 0.02), and running speed (shuttle run: 25.4 ± 4.5 vs. 23.1 ± 4.0 s). Patients with AUD were also significantly less physically active than healthy controls (1020.9 ± 578.8 vs. 1738.7 ± 713.3 MET-minutes/week; p < 0.001). Backward regression analyses demonstrated that older age and higher BMI explained lower physical fitness levels, whereas longer illness duration and impaired explosive muscle strength explained lower total physical activity levels. The current findings suggest that lower physical fitness and physical activity are emerging as prominent modifiable risk factors in patients with AUD. Future research should explore the benefits of specific rehabilitation interventions aimed at increasing physical activity and physical fitness in this vulnerable group.

The Effects of Exercise on IL-6 Levels and Cognitive Performance in Patients with Schizophrenia

Exercise plays an important role in brain plasticity, leading to improvements in cognitive function and delaying the cognitive deterioration of healthy people. These effects can be observed in individuals with schizophrenia through improvements in their performance in cognitive tasks and a decrease in the symptomology of the disease. In this review we examine the current evidence for the roles that exercise and the immune system play in patients with schizophrenia, and specifically analyze the interleukin-6 (IL-6) pathway as a potential mechanism resulting in these positive effects. Inflammation and high levels of IL-6 are associated with both the severity of schizophrenia and the cognitive impairment suffered throughout the disease. Performing regular exercise can modulate IL-6 by lowering its basal levels and by causing lower acute increases in the plasma levels of this cytokine in response to exercise (an anti-inflammatory response to physical exertion). Although there is evidence for the positive effects of physical exercise on schizophrenia, more studies will be required to better understand how variation in different exercise parameters affects both the acute and chronic plasma levels of IL-6.

Cardio-Respiratory Fitness and Autonomic Function in Patients with Major Depressive Disorder

Patients with major depressive disorder (MDD) have an augmented risk of cardiovascular morbidity and mortality. Although a link between depression and autonomic dysfunction as well as reduced cardio-respiratory fitness (CRF) is well documented, the underlying cause is a matter of debate. Therefore, we studied the interplay between autonomic function, body composition and severity of the disease to disentangle possible physiological factors influencing the assumed lack of CRF in MDD patients. We investigated seventeen patients suffering from MDD and seventeen control subjects matched with respect to age, sex, body-mass-index, and smoking habits. A resting baseline assessment and a cardiopulmonary exercise test including a prolonged recovery period were performed to study autonomic function (i.e., heart rate responses and heart rate variability) during rest, exercise and recovery as well as CRF. Most investigated autonomic indices were significantly different at rest, during exercise as well as during recovery indicating altered autonomic modulation. Nevertheless, none of our participants was classified as chronotropically incompetent. As expected, a reduced CRF (i.e., peak oxygen uptake and peak power output, p < 0.01) was observed in patients compared to controls. In addition, a correlation of baseline heart rate and of heart rate during recovery with the ventilatory threshold 1 (p < 0.05) was found in patients only, indicating a relation to the lack of CRF. Furthermore, we observed a positive correlation of the severity of the disease with the weekly sitting time (p < 0.01) as well as a negative correlation with the activity time in the intensity domain walking (p < 0.001) and with the total score of the International Physical Activity Questionnaire (p < 0.01) for patients. This study shows that patients with MDD have altered autonomic function not only during resting conditions but also during exercise as well as recovery from exercise. Intervention studies are needed to evaluate how the described autonomic alterations can be influenced by increasing CRF due to appropriate exercise training programs.

Physical activity pattern and cardiorespiratory fitness in individuals with schizophrenia compared with a population-based sample

OBJECTIVE

Thorough description of objectively assessed physical activity (PA) and sedentary time in people with schizophrenia is lacking, and previous studies comparing PA and cardiorespiratory fitness levels with healthy controls are limited by their small sample size and/or poor methodology.

METHOD

PA, sedentary behavior, and cardiorespiratory fitness level were assessed in 67 adults diagnosed with schizophrenia (EPHAPS study) and compared with a population-based sample of 2809 adults (NPASS study).

RESULTS

Fifty-five percent of the participants with schizophrenia had the unhealthy combination of not meeting the PA recommendations and sitting >7.5 h per day compared to 32% in the population-based sample. The PA level was especially low on weekday afternoons and evenings and throughout most of the day on weekends. The peak oxygen uptake for EPHAPS women was on average 23% lower than that for NPASS women, while EPHAPS men achieved on average 34% lower oxygen uptake on the exercise test compared with NPASS men.

CONCLUSION

People with schizophrenia are significantly less physically active, more sedentary, and have a poorer cardiorespiratory fitness level compared with the general population. Tailor-made PA interventions for people with schizophrenia should target their PA and sedentary behavior on afternoons and weekends especially.

Chronotropic incompetence of the heart is associated with exercise intolerance in patients with schizophrenia

The elevated cardiovascular risk of patients with schizophrenia contributes to a reduced life expectancy of 15-20years. This study investigated whether cardiac autonomic dysfunction (CADF) in schizophrenia is related to chronotropic incompetence, an established cardiovascular risk marker. We investigated thirty-two patients suffering from paranoid schizophrenia and thirty-two control subjects matched for age, sex, body mass index and fat free mass. A cardiopulmonary exercise test (CPET) was performed to study heart rate responses to exercise as well as submaximal (ventilatory threshold 1, VT₁) and maximal endurance capacities (peak oxygen consumption, VO_2peak; peak power output, P_peak). In addition, epinephrine and norepinephrine levels were assessed in a subset of patients. Fitness parameters were significantly reduced in all patients. Most investigated physiological parameters were significantly different at rest as well as during peak exercise being in line with previously described CADF in schizophrenia. In particular, 14 out of 32 patients were classified as chronotropically incompetent whereas no control subject was below the cut-off value. In addition, a positive correlation of a slope reflecting chronotropic incompetence with peak oxygen uptake (p<0.001) was observed in patients only indicating a close correlation to the lack of physical fitness. The catecholamine increase was reduced in patients after exercise. This study identified a novel cardiac risk factor in patients with schizophrenia. Moreover, it seems to be associated with reduced physical fitness and indicates targets for exercise intervention studies. Future studies are warranted to elucidate pathophysiological mechanisms of this cardiac condition.

Cardiorespiratory Fitness in Severe Mental Illness: A Systematic Review and Meta-analysis

BACKGROUND

Cardiorespiratory fitness (CRF) among people with severe mental illness (SMI) (i.e., schizophrenia, bipolar disorder, and major depressive disorder) is a critical clinical risk factor given its relationship to cardiovascular disease and premature mortality.

OBJECTIVES

This study aimed to: (1) investigate the mean CRF in people with SMI versus healthy controls; (2) explore moderators of CRF; and (3) investigate whether CRF improved with exercise interventions and establish if fitness improves more than body mass index following exercise interventions.

METHODS

Major electronic databases were searched systematically. A meta-analysis calculating Hedges' g statistic was undertaken.

RESULTS

Across 23 eligible studies, pooled mean CRF was 28.7 mL/kg/min [95 % confidence interval (CI) 27.3 to 30.0 mL/kg/min, p < 0.001, n = 980]. People with SMI had significantly lower CRF compared with controls (n = 310) (Hedges' g = -1.01, 95 % CI -1.18 to -0.85, p < 0.001). There were no differences between diagnostic subgroups. In a multivariate regression, first-episode (β = 6.6, 95 % CI 0.6-12.6) and inpatient (β = 5.3, 95 % CI 1.6-9.0) status were significant predictors of higher CRF. Exercise improved CRF (Hedges' g = 0.33, 95 % CI = 0.21-0.45, p = 0.001), but did not reduce body mass index. Higher CRF improvements were observed following interventions at high intensity, with higher frequency (at least three times per week) and supervised by qualified personnel (i.e., physiotherapists and exercise physiologists).

CONCLUSION

The multidisciplinary treatment of people with SMI should include a focus on improving fitness to reduce all-cause mortality. Qualified healthcare professionals supporting people with SMI in maintaining an active lifestyle should be included as part of multidisciplinary teams in mental health treatment.

Exercise-induced modulation of histone H4 acetylation status and cytokines levels in patients with schizophrenia

The present study aimed to investigate the short and long-term effects of a concurrent exercise protocol on global histone H4 acetylation levels and inflammatory markers (interleukin-4 (IL-4), interleukin-6 (IL-6), interferon gamma (IFN-γ) and cortisol) in phytohemagglutinin-stimulated peripheral blood mononuclear cells (PBMC) and in peripheral blood of patients with schizophrenia (SZ), as well the intervention impact on anthropometric characteristics. Seventeen individuals were submitted to the intervention three times a week and blood samples were collected pre, 30, 60 and 90days after the intervention started. A remarkable reduction on body mass index and body mass were observed following intervention. The protocol also induced a histone H4 hypoacetylation status in PBMC all times evaluated when compared to the pre intervention period. Although the IL-4 and cortisol levels were not altered in response to the intervention, a reduction in IL-6 production during the 60 and 90days compared to the pre intervention period was observed. Finally, diminished IFN-γ production was found in the 90days period compared to the pre intervention and 30days after periods. In addition, systemic IL-6 levels were lower at 60 and 90days compared to the pre intervention. The concurrent exercise protocol was able to improve anthropometric characteristics in patients with SZ, engaging the modulation of cytokine and histone H4 acetylation levels.

Determining cardiac vagal threshold from short term heart rate complexity

Evaluating individual aerobic exercise capacity is fundamental in sports and exercise medicine but associated with organizational and instrumental effort. Here, we extract an index related to common performance markers, the aerobic and anaerobic thresholds enabling the estimation of exercise capacity from a conventional sports watch supporting beatwise heart rate tracking. Therefore, cardiac vagal threshold (CVT) was determined in 19 male subjects performing an incremental maximum exercise test. CVT varied around the anaerobic threshold AnT with mean deviation of 7.9 ± 17.7 W. A high correspondence of the two thresholds was indicated by Bland-Altman plots with limits of agreement −27.5 W and 43.4 W. Additionally, CVT was strongly correlated AnT (r p = 0.86, p < 0.001) and reproduced this marker well (r c = 0.81). We conclude, that cardiac vagal threshold derived from compression entropy time course can be useful to assess physical fitness in an uncomplicated way.

Sitting time, physical fitness impairments and metabolic abnormalities in people with bipolar disorder: An exploratory study

A sedentary lifestyle is an independent risk factor for cardiovascular disease and mortality. Little is known however about sedentary behavior in people with bipolar disorder (BD). The primary aim of this study was to explore associations between sitting time (as a proxy for a sedentary lifestyle) and physical fitness and metabolic parameters in BD. A secondary aim was to investigate associations between psychiatric symptoms, psychotropic medication use and sitting time. Thirty-nine (21♀) participants (43.7±12.4 years) completed a full metabolic screening, the sitting time item of the International Physical Activity Questionnaire, the Quick Inventory of Depressive Symptomatology self-report and the Hypomania Checklist-32. Additionally participants performed the Eurofit-test battery and 6-min walk test. The mean time spent sitting per day for the entire sample was 7.0±3.0h. A higher body mass index, worse physical fitness and higher antipsychotic medication dose were identified as independent predictors of higher levels of sitting behavior. The model explained 76.5% of the variability in the sitting time. Given that a sedentary lifestyle is an independent predictor of cardiovascular disease, future interventions specifically targeting time spend sitting are warranted in BD, with a particular emphasis on those with high body mass index and low fitness levels.

Endurance training in patients with schizophrenia and healthy controls: differences and similarities

The aims were to examine the feasibility of and adaptations to endurance training in persons diagnosed with schizophrenia and to address the question whether the principles and beneficial effects of endurance training established in the healthy population apply also to patients with schizophrenia. In this controlled interventional study, 22 patients with schizophrenia and 22 healthy controls performed a standardized aerobic endurance training on bicycle ergometers over 12 weeks. Another group of 21 patients with schizophrenia played table soccer. Endurance capacity was measured with incremental cycle ergometry before and after the intervention and 3 months later. A specific set of outcome parameters was defined. The training stimuli can be assumed to be similar in both endurance groups. Endurance capacity improved significantly in the endurance groups, but not in the table soccer group. Patients and healthy controls showed comparable adaptations to endurance training, as assessed by physical working capacity and maximal achieved power. Differences were found in changes of performance at a lactate concentration of 3 mmol/l. Endurance training was feasible and effective in both groups. The principles and types of training that are usually applied to healthy controls need to be verified in patients with schizophrenia. Nevertheless, patients benefited from endurance training in terms of improvement of endurance capacity and reduction in the baseline deficit in comparison with healthy controls. Therefore, endurance training should be implemented in future therapy programs. These programs need to pay special attention to the differences between patients with schizophrenia and healthy controls.

Cardiorespiratory fitness in outpatients with bipolar disorder versus matched controls: An exploratory study

BACKGROUND

Patients with bipolar disorder (BD) are approximately twice as likely to die prematurely due cardiovascular diseases (CVD) than the general population. Cardiorespiratory fitness (CRF) is an important health outcome measure, predictive for CVD and premature mortality.

AIMS

The aim of the current study was to compare the CRF of outpatients with BD versus age-, gender-, and body mass index (BMI)-matched healthy controls (HC). A secondary aim was to assess potential correlates of CRF.

METHODS

All participants underwent a maximal incremental exercise test to measure the maximum oxygen uptake (VO2max, the golden standard assessment of cardiorespiratory fitness), wore a Body Sensewear Armband for 5 subsequent days to assess their physical activity behavior and completed the Positive-and-Negative-Affect-Schedule (PANAS).

RESULTS

Outpatients with BD (n=20; 47.8±7.6years) had a significantly lower VO2max compared with HC (n=20; 47.8±7.6years) (26.0±7.3 versus 30.4±6.5ml/min/kg, P=0.047). A higher VO2max was correlated with younger age, higher active energy expenditure, higher PANAS positive and lower PANAS negative affect scores and a lower antipsychotic medication dose.

LIMITATIONS

The limited sample and cross-sectional design preclude definitive conclusions.

CONCLUSIONS

Compared with HC, outpatients with BD have reduced CRF levels of approximately 4.4ml/min/kg. In the general population such reductions are associated with a 20% increased premature mortality risk. Interventions targeting CRF in BD are required. Although more research is needed, clinicians should consider the utility of objective assessments of CRF for risk stratification in outpatient settings.

Hippocampal-Brainstem Connectivity Associated with Vagal Modulation after an Intense Exercise Intervention in Healthy Men

Regular physical exercise leads to increased vagal modulation of the cardiovascular system. A combination of peripheral and central processes has been proposed to underlie this adaptation. However, specific changes in the central autonomic network have not been described in human in more detail. We hypothesized that the anterior hippocampus known to be influenced by regular physical activity might be involved in the development of increased vagal modulation after a 6 weeks high intensity intervention in young healthy men (exercise group: n = 17, control group: n = 17). In addition to the determination of physical capacity before and after the intervention, we used resting state functional magnetic resonance imaging and simultaneous heart rate variability assessment. We detected a significant increase of the power output at the anaerobic threshold of 11.4% (p < 0.001), the maximum power output Pmax of 11.2% (p < 0.001), and VO2max adjusted for body weight of 4.7% (p < 0.001) in the exercise group (EG). Comparing baseline (T0) and post-exercise (T1) values of parasympathetic modulation of the exercise group, we observed a trend for a decrease in heart rate (p < 0.06) and a significant increase of vagal modulation as indicated by RMSSD (p < 0.026) during resting state. In the whole brain analysis, we found that the connectivity pattern of the right anterior hippocampus (aHC) was specifically altered to the ventromedial anterior cortex, the dorsal striatum and to the dorsal vagal complex (DVC) in the brainstem. Moreover, we observed a highly significant negative correlation between increased RMSSD after exercise and decreased functional connectivity from the right aHC to DVC (r = -0.69, p = 0.003). This indicates that increased vagal modulation was associated with functional connectivity between aHC and the DVC. In conclusion, our findings suggest that exercise associated changes in anterior hippocampal function might be involved in increased vagal modulation.

Therapeutic implications of the choroid plexus-cerebrospinal fluid interface in neuropsychiatric disorders

The choroid plexus (CP) comprises an epithelial monolayer that forms an important physical, enzymatic and immunologic barrier, called the blood-cerebrospinal fluid barrier (BCSFB). It is a highly vascularized organ located in the brain ventricles that is key in maintaining brain homeostasis as it produces cerebrospinal fluid (CSF) and has other important secretory functions. Furthermore, the CP-CSF interface plays a putative role in neurogenesis and has been implicated in neuropsychiatric diseases such as the neurodevelopmental disorders schizophrenia and autism. A role for this CNS border was also implicated in sleep disturbances and chronic and/or severe stress, which are risk factors for the development of neuropsychiatric conditions. Understanding the mechanisms by which disturbance of the homeostasis at the CP-CSF interface is involved in these different chronic low-grade inflammatory diseases can give new insights into therapeutic strategies. Hence, this review discusses the different roles that have been suggested so far for the CP in these neuropsychiatric disorders, with special attention to potential therapeutic applications.

Cumulative stress pathophysiology in schizophrenia as indexed by allostatic load

BACKGROUND

The etiopathophysiology of schizophrenia has long been linked to stress and the influence of stress is important in all stages of the illness. Previous examinations of perceived stress and acute stress responses may not capture this longitudinal stress pathophysiology. We hypothesized that the cumulative negative effects of stress, indexed by allostatic load (AL), would be elevated in schizophrenia, and that the AL paradigm would be relevant to our understanding of pathophysiology in schizophrenia.

METHODS

We assessed allostatic load in 30 patients with schizophrenia (SZ; mean age = 33; 17 males) and 20 healthy controls (HC; mean age = 35; 12 males) using 13 cardiovascular, metabolic, neuroendocrine and immune biomarkers. Participants' perceived stress over the past month, functional capacity and psychiatric symptoms were also measured.

RESULTS

Controlling for age, SZ had significantly higher AL as compared to HC (p = 0.007). Greater AL was present in both early course and chronic SZ, and was associated with reduced functional capacity (p = 0.006) and more psychotic symptoms (p = 0.048) in SZ. Current level of perceived stress was not significantly elevated in SZ or associated with AL in either group.

CONCLUSIONS

The higher AL found in SZ may reflect increased bodily "wear and tear", possibly caused by more chronic stress exposure or maladaptive responses to stress over time, although additional research is required to differentiate these causes. The higher AL is similarly present in early and chronic SZ, suggesting primary maladaptive stress physiology rather than secondary effects from medications or chronic illness.

Promotion of cardiorespiratory fitness in schizophrenia: a clinical overview and meta-analysis

OBJECTIVE

Cardiorespiratory fitness (CRF) is a major modifiable risk factor for cardiovascular disease (CVD). We conducted a clinical overview to highlight the reduced CRF expressed as maximal oxygen uptake (VO2max) (or predicted) or peak oxygen uptake (VO2 peak) in people with schizophrenia compared to the general population. We also aimed to identify correlates of and clinical strategies to improve CRF.

METHOD

We systematically searched major electronic databases from inception until November 2014. A meta-analysis calculating the standardised mean difference (SMD) was employed.

RESULTS

CRF was significantly reduced in people with schizophrenia (n = 154) with a SMD of -0.96 (95% CI -1.29 to -0.64) (N = 5) compared to controls (n = 182). Negative symptoms, increased body mass index and female gender were negatively associated with CRF. Promoting physical activity may improve CRF in people with schizophrenia by up to 4-4.5 ml/kg/min following a 6-8 weeks programme (N = 4, n = 98).

CONCLUSION

People with schizophrenia have a large and significantly reduced CRF. Given the overwhelming evidence for physical activity as the cornerstone of preventing and managing CVD in the general population, incorporating such interventions in the treatment of people with schizophrenia is justified and urgently required. We present clear practical strategies of how this can be achieved within clinical settings.

Cardiac Autonomic Dysfunction in Patients with Schizophrenia and Their Healthy Relatives - A Small Review

The majority of excess mortality among people with schizophrenia seems to be caused by cardiovascular complications, and in particular, coronary heart disease. In addition, the prevalence of heart failure and arrhythmias is increased in this population. Reduced efferent vagal activity, which has been consistently described in these patients and their healthy first-degree relatives, might be one important mechanism contributing to their increased cardiac mortality. A decrease in heart rate variability and complexity was often shown in unmedicated patients when compared to healthy controls. In addition, faster breathing rates, accompanied by shallow breathing, seem to influence autonomic cardiac functioning in acute unmedicated patients substantially. Moreover, low-physical fitness is a further and independent cardiac risk factor present in this patient population. Interestingly, new studies describe chronotropic incompetence during physical exercise as an important additional risk factor in patients with schizophrenia. Some studies report a correlation of the autonomic imbalance with the degree of positive symptoms (i.e., delusions) and some with the duration of disease. The main body of psychiatric research is focused on mental aspects of the disease, thereby neglecting obvious physical health needs of these patients. Here, a joint effort is needed to design interventional strategies in everyday clinical settings to improve physical health and quality of life.

Health-related physical fitness in patients with bipolar disorder vs. healthy controls: an exploratory study

BACKGROUND

Low physical fitness has been recognized as a prominent behavioral risk factor for cardiovascular diseases and an independent risk factor for all-cause mortality. To date, no studies have systematically assessed physical fitness in patients with bipolar disorder. The aim of the current study was to assess and compare the physical fitness in patients with bipolar disorder against healthy controls.

METHODS

Thirty patients with bipolar disorder (16♂, 40.8±11.6 years) and 30 age-, gender- and body mass index (BMI)-matched healthy controls were included. All participants performed the Eurofit test battery and the International Physical Activity Questionnaire. Patients were screened for psychiatric symptoms using the Quick Inventory of Depressive Symptomatology and Hypomania Checklist-32.

RESULTS

Patients with bipolar disorder had a reduced speed of limb movement (15.8±5.7 vs. 11.8±2.2s; p<0.001), explosive leg muscle strength (134.9±49.0 vs. 167.6±32.3cm; p=0.003) and abdominal muscular endurance (11.5±7.8 vs. 18.3±7.6; p<0.001). Backward regression analyses demonstrated that longer illness duration, higher body mass index, higher levels of depression and a lower physical activity level explained the variance in physical fitness.

LIMITATIONS

Our data are cross-sectional and cannot establish cause and effect.

CONCLUSIONS

The current findings suggest that a lower physical fitness is emerging as an eminent modifiable risk factor for somatic co-morbidity in people with bipolar disorder. In particular less physically active persons, those with a longer illness duration and those with higher levels of depression might benefit from specific rehabilitation interventions aimed at increasing physical fitness.

Associations between metabolic and aerobic fitness parameters in patients with schizophrenia

The primary aim was to determine whether the presence of metabolic syndrome (MetS) limits aerobic fitness in patients with schizophrenia. A secondary aim was to investigate the associations between aerobic fitness and MetS parameters. Aerobic fitness (expressed as predicted maximal oxygen uptake) was assessed using the Astrand-Rhyming test. Those with MetS (n = 19) were similar in age, sex, antipsychotic medication use, symptoms, and smoking behavior than those without (n = 31). Estimated maximal oxygen uptake was 21.4% lower (p = 0.001) in patients with MetS than in patients without MetS (29.5 ± 7.4 ml of O2/min/kg vs. 37.5 ± 8.2 ml of O2/min/kg, respectively). The estimated maximal oxygen uptake of the entire sample was correlated with waist circumference, the level of high-density lipoproteins, and fasting glucose. The current study demonstrates that the additive burden of MetS might place people with schizophrenia at increased risk for functional limitations in daily life activities.

Effects of exercise training with traditional dancing on functional capacity and quality of life in patients with schizophrenia: a randomized controlled study

OBJECTIVE

To examine the effects of an eight-month exercise training programme with Greek traditional dancing on functional capacity and quality of life in patients with schizophrenia.

DESIGN

Randomized controlled trial.

SETTING

Sports Medicine Laboratory.

SUBJECTS

A total of 31 patients, aged 59.9 ± 14.1 years.

INTERVENTIONS

They were randomly assigned either to a Greek traditional dancing programme (Group A) or to a sedentary control group (Group B).

MAIN MEASURES

A functional capacity assessment was performed at baseline and the end of the study. Global Assessment of Functioning Scale and Positive and Negative Syndrome Scale were also used. Quality of life was examined using the Quality of Life and Satisfaction questionnaire.

RESULTS

After the eight months, Group A increased walking distance in the 6-minute walk test (328.4 ± 35.9 vs. 238.0 ± 47.6 m), sit-to-stand test (19.1 ± 1.8 vs. 25.1 ± 1.4 seconds), Berg Balance Scale score (53.1 ± 2.1 vs. 43.2 ± 6.7), lower limbs maximal isometric force (77.7 ± 25.7 vs. 51.0 ± 29.8 lb), Positive and Negative Syndrome Scale total score (77.0 ± 23.1 vs. 82.0 ± 24.4), Global Assessment of Functioning Scale total score (51.3 ± 15.5 vs. 47.7 ± 13.3) and Quality of Life total score (34.9 ± 5.2 vs. 28 ± 4.5), compared with Group B.

CONCLUSIONS

Our results demonstrate that Greek traditional dances improve functional capacity and quality of life in patients with schizophrenia.

Differential cardiac effects of aerobic interval training versus moderate continuous training in a patient with schizophrenia: a case report

Increased cardiovascular morbidity and mortality rates for patients with schizophrenia are reported to contribute to their reduced life expectancy. Common reasons for increased cardiac mortality rates include cigarette smoking, obesity, dyslipidemia, diabetes, and poorer health behavior in general. The majority of excess mortality among people with schizophrenia is caused by cardiovascular complications. Reduced vagal activity might be one important mechanism leading to this increased cardiac mortality and has been consistently described in patients and their healthy first-degree relatives. In this case study, we compared two different aerobic exercise regimes in one patient with chronic schizophrenia to investigate their effects on cardiovascular regulation. The patient completed a 6-week period of moderate continuous training (CT) followed by a 6-week period of interval training (IT), each regime two times per week, on a stationary bicycle. This was followed by a 6-week period of detraining. Primary outcome measures examined heart rate (HR) and heart rate variability (HRV) at rest while secondary measures assessed fitness parameters such as the ventilatory threshold 1 (VT1). We observed that IT was far more effective than moderate CT in increasing HRV, as indicated by root mean of squared successive difference (improvement to baseline 27 versus 18%), and reducing resting HR (-14 versus 0%). Improvement in VT1 (21 versus -1%) was only observed after IT. Our study provides preliminary data that the type of intervention is highly influential for improving cardiac function in patients with schizophrenia. While cardiovascular function might be influenced by CT to some degree, no such effect was present in this patient with schizophrenia. In addition, the beneficial effect of IT on HR regulation vanished completely after a very short period of detraining after the intervention.