Hilary F. Armstrong

Aerobic fitness and body mass index in individuals with schizophrenia: Implications for neurocognition and daily functioning

Previous reports indicate that among healthy individuals low aerobic fitness (AF) and high body-mass index (BMI) predict poor neurocognition and daily-functioning. It is unknown whether these associations extend to disorders characterized by poor neurocognition, such as schizophrenia. Therefore, we compared AF and BMI in individuals with schizophrenia and non-clinical controls, and then within the schizophrenia group we examined the links between AF, BMI, neurocognition and daily-functioning. Thirty-two individuals with schizophrenia and 64 gender- and age-matched controls completed assessments of AF (indexed by VO2max) and BMI. The former also completed measures of neurocognition, daily-functioning and physical activity. The schizophrenia group displayed significantly lower AF and higher BMI. In the schizophrenia group, AF was significantly correlated with overall neurocognition (r=0.57), along with executive functioning, working memory, social cognition, and processing speed. A hierarchical regression analysis indicated that AF accounted for 22% of the neurocognition variance. Furthermore, AF was significantly correlated with overall daily-functioning (r=0.46). In contrast, BMI displayed significant inverse correlations with neurocognition, but no associations to daily-functioning. AF was significantly correlated physical activity. The authors discuss the potential use of AF-enhancing interventions to improve neurocognitive and daily-functioning in schizophrenia, along with putative neurobiological mechanisms underlying these links, including Brain-Derived Neurotrophic Factor.

High attenuation areas on chest computed tomography in community-dwelling adults: the MESA study

Evidence suggests that lung injury, inflammation and extracellular matrix remodelling precede lung fibrosis in interstitial lung disease (ILD). We examined whether a quantitative measure of increased lung attenuation on computed tomography (CT) detects lung injury, inflammation and extracellular matrix remodelling in community-dwelling adults sampled without regard to respiratory symptoms or smoking. We measured high attenuation areas (HAA; percentage of lung voxels between −600 and −250 Hounsfield Units) on cardiac CT scans of adults enrolled in the Multi-Ethnic Study of Atherosclerosis. HAA was associated with higher serum matrix metalloproteinase-7 (mean adjusted difference 6.3% per HAA doubling, 95% CI 1.3–11.5), higher interleukin-6 (mean adjusted difference 8.8%, 95% CI 4.8–13.0), lower forced vital capacity (FVC) (mean adjusted difference −82 mL, 95% CI −119–−44), lower 6-min walk distance (mean adjusted difference −40 m, 95% CI −1–−80), higher odds of interstitial lung abnormalities at 9.5 years (adjusted OR 1.95, 95% CI 1.43–2.65), and higher all cause-mortality rate over 12.2 years (HR 1.58, 95% CI 1.39–1.79). High attenuation areas are associated with biomarkers of inflammation and extracellular matrix remodelling, reduced lung function, interstitial lung abnormalities, and a higher risk of death among community-dwelling adults. Increased lung attenuation on CT may identify subclinical lung injury and inflammation in community-dwelling adults http://ow.ly/97k3300tvKX

Evaluation of Pulmonary Function and Exercise Performance by Cardiopulmonary Exercise Testing Before and After Lung Transplantation

BACKGROUND Detailed description of functional exercise outcomes before and after lung transplantation is lacking. The objective of this study was to describe and compare posttransplant improvement in lung function and peak exercise parameters in patients with advanced lung disease. METHODS The study included 153 patients who underwent lung transplantation over 7 years who had complete cardiopulmonary exercise testing (CPET) and pulmonary function tests (PFTs) before and after lung transplantation. CPET and PFT within 30 months pretransplant and posttransplant were compared. RESULTS Pulmonary function markedly improved posttransplant as FVC increased 67%, maximum voluntary ventilation increased 91%, and FEV(1) increased 136%. However, peak oxygen consumption increased only 19%, peak CO(2) production increased 50%, and peak work increased 78%. Although transplant recipients had a 1.5- to 2.0-fold increase in exercise capacity posttransplant, peak exercise capacity remained at 50% of the predicted normal, suggesting a maximal limitation. Subgroup stratification into quartiles based on pretransplant exercise capacity revealed the greatest exercise benefit to be in the lowest functional pretransplant groups. CONCLUSIONS Lung transplant recipients have an increase in exercise capacity that does not match the improvement in lung function, indicating that poor strength, deconditioning, or other peripheral factors play a significant role in the limitation of exercise benefit posttransplantation. Further elucidation of the mechanisms of exercise limitation may allow for improved exercise outcomes posttransplant.

Aerobic exercise for cognitive deficits in schizophrenia — The impact of frequency, duration, and fidelity with target training intensity

Individualswith schizophrenia display substantial deficits in cognitive functioning (Green et al., 2004) for which available treatments offer only limited benefits. Recent reports have indicated that aerobic exercise (AE) leads to improvements in both aerobic fitness (AF; Vancampfort et al., 2015; Armstrong et al., submitted for publication) and cognitive functioning among individual with schizophrenia (Kimhy et al., 2015; Kimhy et al., 2014). A recent review of trials examining exercise interventions in people with schizophrenia have suggested that clinical benefits from such trials are related to the dose of exercise, with interventions employing at least 90min of moderate-to-vigorous exercise per week result in clinical improvements (i.e., Firth et al., 2015). However, the specific AE training characteristics that contribute to cognitive improvements remain largely unknown. To address this issue, we examined the impact of frequency, duration, and fidelity with target training intensity on changes in cognition in 13 individuals with schizophrenia (average age = 36.31, SD = 11.16; 38% female) who completed an AE training program as part of a single-blind randomized clinical trial examining the impact of AE on cognition (Kimhy et al., 2015). Detailed descriptions of the trial and the AE procedures have been published elsewhere (Kimhy et al., 2015; Kimhy et al., in press). Briefly, the AE program was informed by the American College of Sports Medicine and federal guidelines for the frequency, intensity, time, and type of AE (US Department of Health and Human Services, 2008). The program involved three one-hour AE sessions/week over 12 weeks. The sessions opened with a 10-min warm-up period, after which participants exercised individually for 45 min, ending with a 5-min cool-down period. A trainer was present during the AE sessions for guidance and support, along with a research assistant who collected behavioral data. Changes in cognitive functioning from baseline to 12 weeks were indexed by changes in the composite scores of the MATRICS Consensus Cognitive Battery. Additionally, at baseline participants completed a cardiopulmonary exercise test (CPET) to determine their AF (VO2 peak; ml/kg/min) and maximal heart rate (HRmax). The latter was used to determine the in-session target AE training intensity for each participant. Targets were set to 60% of HRmax in week 1, 65% in week 2, 70% in week 3, and 75% in weeks 4–12. The AE intensity was indexed by the in-session heart rate recorded using Polar RS400 heart rate monitors (Polar Electro Inc., Lake Success, NY) worn by participants during sessions. The monitors were programmed to emit a soft beep if a participants heart rate fell below the individually-targeted AE intensity level for a particular week of training. On such occasions, the trainer encouraged the participant to achieve their target goal. Following the completion of the 12-week training program, all participants completed a second CPET to determine changes in AF.

Impact of pulmonary hypertension on exercise performance in patients with interstitial lung disease undergoing evaluation for lung transplantation

Pulmonary hypertension (PH) is a known complication in patients with interstitial lung disease (ILD). Cardiopulmonary exercise testing (CPET) is an essential tool for the assessment of patients with cardiac and pulmonary diseases due to its prognostic and therapeutic implications. Few studies have evaluated the relationship between CPET response and mean pulmonary artery pressures (mPAP) in ILD. The purpose of the present study was to determine and compare the potential correlations between CPET, 6‐min walk test (6MWT), pulmonary function testing (PFT) and PH in patients with ILD being evaluated for lung transplantation.

Right ventricular stroke work index as a negative predictor of mortality and initial hospital stay after lung transplantation

BACKGROUND Studies have shown that patients with poor pre-lung transplant (LTx) right ventricular (RV) function have prolonged post-operative ventilation time and intensive care stay as well as a higher risk of in-hospital death. RV stroke work index (RVSWI) calculates RV workload and contractility. We hypothesized that patients with higher RV workload capacity, indicated by higher RVSWI, would have better outcomes after LTx. METHODS A retrospective record review was performed on all LTx patients between 2005 and 2011 who had right heart catheterizations (RHC) 1-year before LTx. In addition, results for echocardiograms and cardiopulmonary exercise testing within 1-year of RHCs were gathered. RESULTS Mean RVSWI was 9.36 ± 3.59 for 115 patients. There was a significant relation between mean pulmonary artery pressure (mPAP), RVSWI, RV end-diastolic diameter (RVEDd), left atrial dimension (LAD), peak and resting pressure of end-tidal carbon dioxide, minute ventilation /volume of carbon dioxide production, and 1-year mortality after LTx. Contrary to our hypothesis, those who survived had lower RVSWI than those who died within 1 year (8.99 ± 3.38 vs 11.6 ± 4.1, p = 0.026). Hospital length of stay significantly correlated with mPAP, RVSWI, left ventricular ejection fraction, percentage of fractional shortening, RVEDd, RV fractional area change, LAD, and RV wall thickness in diastole. Intensive care length of stay also significantly correlated with these variables and with body mass index. RVSWI was significantly different between groups of different RV function, indicating that increased RVSWI is associated with impairment of RV structure and function in patients undergoing LTx evaluation. CONCLUSIONS This study demonstrates an association between 1-year mortality, initial hospital and intensive care length of stay, and pre-LTx RVSWI. Increased mPAP is a known risk for outcomes in LTx patients. Our findings support this fact and also show increased mortality with elevation of RVSWI, demonstrating the value of RV function in the assessment of risk for pre-LTx patients.

Use of Active-Play Video Games to Enhance Aerobic Fitness in Schizophrenia: Feasibility, Safety, and Adherence

OBJECTIVE Active-play video games have been used to enhance aerobic fitness in various clinical populations, but their use among individuals with schizophrenia has been limited. METHODS Feasibility, acceptability, safety, and adherence data were obtained for use of aerobic exercise (AE) equipment by 16 individuals with schizophrenia during a 12-week AE program consisting of three one-hour exercise sessions per week. Equipment included exercise video games for Xbox 360 with Kinect motion sensing devices and traditional exercise equipment. RESULTS Most participants (81%) completed the training, attending an average of 79% of sessions. The proportion of time spent playing Xbox (39%) exceeded time spent on any other type of equipment. When using Xbox, participants played 2.24±1.59 games per session and reported high acceptability and enjoyment ratings, with no adverse events. CONCLUSIONS Measures of feasibility, acceptability, adherence, and safety support the integration of active-play video games into AE training for people with schizophrenia.

Optoelectronic plethysmography compared to spirometry during maximal exercise

The purpose of this study was to compare simultaneous measurements of tidal volume (Vt) by optoelectronic plethysmography (OEP) and spirometry during a maximal cycling exercise test to quantify possible differences between methods. Vt measured simultaneously by OEP and spirometry was collected during a maximal exercise test in thirty healthy participants. The two methods were compared by linear regression and Bland-Altman analysis at submaximal and maximal exercise. The average difference between the two methods and the mean percentage discrepancy were calculated. Submaximal exercise (SM) and maximal exercise (M) Vt measured by OEP and spirometry had very good correlation, SM R=0.963 (p<0.001), M R=0.982 (p<0.001) and high degree of common variance, SM R(2)=0.928, M R(2)=0.983. Bland-Altman analysis demonstrated that during SM, OEP could measure exercise Vt as much as 0.134 L above and -0.025 L below that of spirometry. OEP could measure exercise Vt as much as 0.188 L above and -0.017 L below that of spirometry. The discrepancy between measurements was -2.0 ± 7.2% at SM and -2.4 ± 3.9% at M. In conclusion, Vt measurements at during exercise by OEP and spirometry are closely correlated and the difference between measurements was insignificant.

Exercise ventilatory kinematics in endurance trained and untrained men and women

To determine how increased ventilatory demand impacts ventilatory kinematics, we compared the total chest wall volume variations (V(CW)) of male and female endurance-trained athletes (ET) to untrained individuals (UT) during exercise. We hypothesized that training and gender would have an effect on V(CW) and kinematics at maximal exercise. Gender and training significantly influenced chest wall kinematics. Female ET did not change chest wall end-expiratory volume (V(CW,ee)) or pulmonary ribcage (V(RCp,ee)) with exercise, while female UT significantly decreased V(CW,ee) and V(RCp,ee) with exercise (p<0.05). Female ET significantly increased pulmonary ribcage end-inspiratory volume (V(RCp,ei)) with exercise (p<0.05), while female UT did not change V(RCp,ei) with exercise. Male ET significantly increased V(RCp,ei) with exercise (p<0.05); male UT did not. Men and women had significantly different variation of V(CW) (p<0.05). Women demonstrated the greatest variation of V(CW) in the pulmonary ribcage compartment (V(RCp)). Men had even volumes variation of the V(RCp) and the abdomen (V(Ab)). In conclusion, gender and training had a significant impact on ventilatory kinematics.

Differences in gas exchange between severities of chronic obstructive pulmonary disease

Impaired ventilation on cardiopulmonary exercise test (CPET) is seen in patients with chronic obstructive pulmonary disease (COPD). However, evaluation of the differences of abnormal gas exchange in COPD according to GOLD severity criteria is limited. A retrospective review was performed on all COPD patients referred for CPET at our center between 1998 and 2010. There were 548 patients compared according to GOLD severity. GOLD groups were significantly different from each other in regards to pressure of end-tidal carbon dioxide ( [Formula: see text] ) with progressively higher [Formula: see text] with increasing GOLD severity. Ratio of minute ventilation to carbon dioxide production ( [Formula: see text] ) and exercise capacity as measured by and [Formula: see text] % and work rate in watts% was inversely proportional to GOLD severity. Breathing reserve, minute ventilation, and tidal volume at peak exercise were significantly decreased with increasing disease severity between GOLD groups. We concluded that gas exchange is distinctive among different GOLD severity groups; specifically, GOLD 3 and 4 have a significantly higher [Formula: see text] and a significantly lower [Formula: see text] than GOLD 2.