Projected Cost Savings of a Community Health Worker Model for Asthma Home Visits in the Massachusetts Pediatric Medicaid Population.

Introduction: The community health worker-led asthma home visiting model (CHW model) improved asthma outcomes and reduced health care costs among Massachusetts children with asthma. We projected cost savings associated with the expansion of the CHW model among pediatric Massachusetts Medicaid (MassHealth)-eligible patients with uncontrolled asthma (≥2 asthma-related emergency department visits per year). Methods: We estimated 2019 costs associated with asthma-related hospitalizations and emergency department visits for MassHealth pediatric patients with uncontrolled asthma who also had 365 days of Medicaid eligibility in 2019. We based estimated cost savings on previously published results from a study of a comparable patient population. Results: The projected asthma-related cost savings from expansion of the CHW model were $566.58 per patient, or $774,514.86 total, for the 1,367 MassHealth-eligible children with uncontrolled asthma in our analysis. Conclusion: Expansion of the CHW model is an effective way to increase asthma services and reduce Medicaid costs for MassHealth patients, a population made up disproportionately of Black and Hispanic residents with low incomes.

Can green firebreaks help balance biodiversity, carbon storage and wildfire risk?

Green firebreaks (strategically placed plantings of low-flammability vegetation) are designed to reduce the rate of fire spread and thereby increase the suppressibility of fires. Successful examples have led to some fire-prone regions investing heavily in the establishment of green firebreaks as a method of reducing fire risk while improving biodiversity and carbon storage. However, beyond small-scale case studies there has been little research quantitatively exploring the interactions among biodiversity, carbon, and wildfire risk in relation to green firebreaks. Here, we combine a Bayesian Network (BN) analysis, and fire simulations in PHOENIX RapidFire (hereafter Phoenix), to identify planting designs that reduce wildfire risks while also providing positive biodiversity and carbon outcomes. Using a BN analysis, we prioritised optimal planting designs as the combination of elements (e.g., stem density, distance from houses, shrub design, age etc.) that delivered the greatest increase in biodiversity and carbon while reducing fire risk to people and property for eight sites across south-eastern Australia. We ranked combinations of planting designs, prioritising house, and life loss first, to identify optimal designs. Optimal planting designs varied among sites, although the design elements that best reduced risk to houses and lives were consistent. These elements included 'scattered' shrubs and planting densities of trees consistent with an open forest structure. Estimated fuel loads for the optimal planting design at each site were used to create a simulated revegetation area in Phoenix. We simulated fire behaviour in Phoenix across a grid of ∼1000 ignitions for each site, and for up to 54 historic weather conditions for a 'current fuel' scenario (no green firebreaks present) compared with a 'green firebreak fuel' scenario. We found that the establishment of a green firebreak did not result in significant changes to fire behaviour at most sites. In some cases, it reduced risk to people and property, and where fire behaviour did change in terms of intensity, frequency, ember attack and overall risk, the differences relative to the current fuel scenario were less than two percent. Overall, simulated green firebreaks in most cases were found to provide biodiversity and carbon benefits without increasing fire risk. These findings illustrate their potential as an effective nature-based solution for managing multiple priorities; however, further testing of real plantings is required to evaluate this potential as an at-scale solution.

Effects of resistance exercise alone or with caffeine on hemodynamics, autonomic modulation and arterial stiffness in resistance-trained women.

AIM: Both an acute bout of resistance exercise (RE) and caffeine consumption can significantly alter hemodynamics, autonomic modulation, and arterial stiffness, which may correlate with adverse cardiovascular events. However, effects of an acute bout of RE and caffeine are unclear in resistance-trained women. PURPOSE: The purpose of this study was to compare the effects of an acute bout of RE with repetitions to failure on squat and bench press, with or without caffeine, on performance, resting and recovery measures of hemodynamics, autonomic modulation, as well as arterial stiffness in resistance-trained women. METHODS: Eleven women participated in a double-blind, placebo controlled cross-over design in which they consumed caffeine (4 mg/kg) or placebo at least 72 h apart. Sixty minutes following ingestion, participants performed two sets of 10 repetitions followed by a third set to failure on squat and bench press. Hemodynamics, autonomic modulation, and arterial stiffness were measured at rest, 60 min post-ingestion, and three minutes and 10 min following RE. RESULTS: Data demonstrated caffeine has no additive effects on performance, hemodynamics, autonomic modulation, or arterial stiffness (p > 0.05) before or following an acute bout of RE in resistance-trained women compared to a placebo. CONCLUSIONS: Resistance-trained women may not observe any alteration to RE performance on the squat and bench press in terms of repetitions to failure following caffeine ingestion. In addition, the data from the present study suggests that there may also not be any further negative effects on the cardiovasculature if caffeine is consumed prior to the RE bout.

Costs of preventing and supressing wildfires in Victoria, Australia.

Land managers around the world are increasingly under pressure to demonstrate that the actions being used to moderate wildfire risk are effective and cost-efficient. However, little research to date has focused on determining cost-efficiency of management actions or identified the factors which increase the costs of performing such actions. Here, we aimed to identify the key drivers of cost for fuel management (prescribed burning, mulching, and slashing), fuel breaks, and suppression using data from the state of Victoria, Australia. We utilise generalised additive models to understand how environmental factors, terrain, location, and management decisions influence the cost of implementing wildfire management efforts. These models show that cost per unit declines as the area treated or the area of the fire increases for all four management approaches. Therefore, preventative, and responsive management actions represent economies of scale that reduce in cost with larger treatments. We also found that there were regional differences in the cost of fuel management and fuel breaks, potentially related to the structure of resourcing treatments in each region and the availability of land on which it is feasible to implement management. Cost of suppression per fire increased with the number of fire fighters and when there were more fires occurring concurrently in the landscape. Identifying the key drivers of cost for preventative and responsive management actions could enable managers to allocate resources to these actions more efficiently in future. Understanding drivers of cost-efficiency could be critical for adapting management to shifts in wildfire risk, particularly given climate change will alter the window in which it is safe to apply some preventative fuel management actions and reduce suppression effectiveness.

Quantifying the impact of vegetation-based metrics on species persistence when choosing offsets for habitat destruction.

Developers are often required by law to offset environmental impacts through targeted conservation actions. Most offset policies specify metrics for calculating offset requirements, usually by assessing vegetation condition. Despite widespread use, there is little evidence to support the effectiveness of vegetation-based metrics for ensuring biodiversity persistence. We compared long-term impacts of biodiversity offsetting based on area only; vegetation condition only; area × habitat suitability; and condition × habitat suitability in development and restoration simulations for the Hunter Region of New South Wales, Australia. We simulated development and subsequent offsetting through restoration within a virtual landscape, linking simulations to population viability models for 3 species. Habitat gains did not ensure species persistence. No net loss was achieved when performance of offsetting was assessed in terms of amount of habitat restored, but not when outcomes were assessed in terms of persistence. Maintenance of persistence occurred more often when impacts were avoided, giving further support to better enforce the avoidance stage of the mitigation hierarchy. When development affected areas of high habitat quality for species, persistence could not be guaranteed. Therefore, species must be more explicitly accounted for in offsets, rather than just vegetation or habitat alone. Declines due to a failure to account directly for species population dynamics and connectivity overshadowed the benefits delivered by producing large areas of high-quality habitat. Our modeling framework showed that the benefits delivered by offsets are species specific and that simple vegetation-based metrics can give misguided impressions on how well biodiversity offsets achieve no net loss.

Cuantificación del Impacto de las Medidas Basadas en la Vegetación sobre la Persistencia de las Especies cuando se Eligen las Compensaciones por la Destrucción del Hábitat Resumen Con frecuencia se requiere por ley que los desarrolladores compensen los impactos ambientales por medio de acciones de conservación. La mayoría de las políticas de compensación especifican medidas para calcular los requerimientos de cada compensación, generalmente mediante la evaluación de las condiciones de la vegetación. A pesar del uso extenso de estas medidas basadas en la vegetación, existe muy poca evidencia que respalde su efectividad para asegurar la persistencia de la biodiversidad. Comparamos los impactos a largo plazo de las compensaciones de biodiversidad basadas solamente en el área; solamente en la condición de la vegetación; la idoneidad del área x hábitat; y la idoneidad condición x hábitat en las simulaciones de desarrollo y restauración para la Región Hunter de Nueva Gales del Sur, Australia. Simulamos el desarrollo y las compensaciones subsecuentes mediante la restauración dentro de un paisaje virtual, conectando las simulaciones con los modelos de viabilidad poblacional para tres especies. Las ganancias del hábitat no aseguraron la persistencia de las especies. No hubo pérdida neta cuando el desempeño de las compensaciones se evaluó en relación con la persistencia. El mantenimiento de la persistencia ocurrió más seguido cuando se evitaron los impactos, lo que proporciona un mayor respaldo para mejorar la aplicación de la fase de prevención de la jerarquía de mitigación. Cuando el desarrollo afectó a las áreas con una alta calidad de hábitat para las especies, no se pudo garantizar la persistencia. Por lo tanto, las especies deben considerarse más explícitamente en las compensaciones, en lugar de sólo considerar a la vegetación o al hábitat. Las declinaciones causadas por la falta de consideración directa de las dinámicas poblacionales de las especies y de la conectividad opacaron los beneficios producidos por las grandes áreas de hábitat de alta calidad. Nuestro marco de trabajo para el modelado demostró que los beneficios producidos por las compensaciones son específicos para cada especie y que las medidas simples basadas en la vegetación pueden brindar impresiones mal informadas sobre qué tanto influyen las compensaciones de biodiversidad en la no pérdida neta.

Vascular Responses to High-Intensity Battling Rope Exercise between the Sexes.

The purpose of the study was to assess high-intensity battling rope exercise (HI-BRE) on hemodynamics, pulse wave reflection and arterial stiffness during recovery and between sexes. Twenty-three young, healthy resistance-trained individuals (men: n = 13; women: n = 10) were assessed for all measures at Rest, as well as 10-, 30-, and 60-minutes following HI-BRE. A one-way repeated measures ANOVA was used to analyze the effects of HI-BRE across time (Rest, 10, 30, and 60-minutes) on all dependent variables. Significant main effects were analyzed using paired t-tests with a Sidak correction factor. Significance was accepted a priori at p 0.05. There were significant reductions in hemodynamic measures of diastolic blood pressure (BP) in women, but not men following HI-BRE at 30 minutes. Further, measures of pulse wave reflection, specifically those of the augmentation index (AIx) and wasted left ventricular energy (ΔEw), were significantly increased in both men and women for 60 minutes, but changes were significantly attenuated in women suggesting less ventricular work. There were also significant increases in arterial stiffness in regard to the aorta and common carotid artery that were fully recovered by 30 and 60 minutes, respectively with no differences between men and women. Thus, the primary findings of this study suggest that measures of hemodynamics and pulse wave reflection are collectively altered for at least 60 minutes following HI-BRE, with women having attenuated responses compared to men.

Home Visits for Children With Asthma Reduce Medicaid Costs.

We conducted a multicomponent, low-cost, home intervention for children with uncontrolled asthma, the Reducing Ethnic/Racial Asthma Disparities in Youth (READY) study, to evaluate its effect on health outcomes and its return on investment. From 2009 through 2014 the study enrolled 289 children aged 2 to 13 years with uncontrolled asthma and their adult caregivers in Boston and Springfield, Massachusetts. Community health workers (CHWs) led in-home asthma management and environmental trigger remediation education over 5 visits spanning 6 months. Asthma health outcomes and indoor environment data were collected via survey, and health use costs were accessed through Massachusetts Medicaid (MassHealth). Results showed significant improvements in asthma control, health care use, and environmental trigger reduction and a positive return on investment (1.34) for participants who had 2 or more emergency department visits 1 year prior to the first home visit. The CHW asthma home visiting intervention improved trigger management, clinical outcomes, and Medicaid cost savings, demonstrating that asthma home visits improve health quality and reduce costs.

Autonomic modulation following an acute bout of bench press with and without blood flow restriction.

PURPOSE: Traditional resistance exercise decreases vagal tone up to 30 min after an acute bout of resistance exercise, which may increase the risk of cardiovascular events. However, the effects of resistance exercise with blood flow restriction (BFR) on autonomic modulation are unclear. To evaluate autonomic modulation after resistance exercise with and without BFR in resistance-trained men. METHODS: Eleven young men volunteered for the study. Autonomic modulation was assessed at rest, 15 (Rec 1), and 25 (Rec 2) minutes after low-load bench press with BFR (LL-BFR), traditional high-load bench press (HL), and a control (CON). Autonomic modulation assessments were expressed as natural logarithm (Ln), and included total power (LnTP), low-frequency power (LnLF), high-frequency power (LnHF), sympathovagal balance (LnLF/LnHF ratio), root mean square of the successive differences (LnRMSSD), and the proportion of intervals differing by > 50 ms from the preceding intervals (LnPNN50). A repeated measures ANOVA was used to evaluate conditions (LL-BFR, HL and CON) across time (Rest, Rec1, and Rec2) on autonomic modulation. RESULTS: There were significant condition by time interactions for LnTP, LnHF, and LnRMSSD such that they were reduced during recovery after LL-BFR and HL compared to Rest and CON. There were no interactions in the LnLF, LnLF/LnHF ratio, and LnPNN50. CONCLUSIONS: These data suggest that LL-BFR and HL significantly alter autonomic modulation up to 30 min after exercise with significant reduction after HL compared to LL-BFR when exercise volume is equated.

Imaging glial activation in patients with post-treatment Lyme disease symptoms: a pilot study using [11C]DPA-713 PET.

The pathophysiology of post-treatment Lyme disease syndrome (PTLDS) may be linked to overactive immunity including aberrant activity of the brain's resident immune cells, microglia. Here we used [11C]DPA-713 and positron emission tomography to quantify the 18 kDa translocator protein, a marker of activated microglia or reactive astrocytes, in the brains of patients with post-treatment Lyme disease symptoms of any duration compared to healthy controls. Genotyping for the TSPO rs6971 polymorphism was completed, and individuals with the rare, low affinity binding genotype were excluded. Data from eight brain regions demonstrated higher [11C]DPA-713 binding in 12 patients relative to 19 controls. [11C]DPA-713 PET is a promising tool to study cerebral glial activation in PTLDS and its link to cognitive symptoms.

Evaluation of the Environmental Scoring System in Multiple Child Asthma Intervention Programs in Boston, Massachusetts.

OBJECTIVES: To test the applicability of the Environmental Scoring System, a quick and simple approach for quantitatively measuring environmental triggers collected during home visits, and to evaluate its contribution to improving asthma outcomes among various child asthma programs. METHODS: We pooled and analyzed data from multiple child asthma programs in the Greater Boston Area, Massachusetts, collected in 2011 to 2016, to examine the association of environmental scores (ES) with measures of asthma outcomes and compare the results across programs. RESULTS: Our analysis showed that demographics were important contributors to variability in asthma outcomes and total ES, and largely explained the differences among programs at baseline. Among all programs in general, we found that asthma outcomes were significantly improved and total ES significantly reduced over visits, with the total Asthma Control Test score negatively associated with total ES. CONCLUSIONS: Our study demonstrated that the Environmental Scoring System is a useful tool for measuring home asthma triggers and can be applied regardless of program and survey designs, and that demographics of the target population may influence the improvement in asthma outcomes.

The Launch of Massachusetts Community Health Worker Certification: Findings From the Massachusetts Community Health Worker Workforce Surveys.

OBJECTIVES: The launch of state certification for community health workers (CHWs) in Massachusetts in 2018 aimed to promote and champion this critical workforce. However, concerns exist about unintentional adverse effects of certification. Given this, we conducted 2 cross-sectional surveys to evaluate this certification policy. METHODS: We conducted surveys of CHW employers and CHWs in 3 sample frames: community health centers and federally qualified health centers, acute-care hospitals, and community-based organizations. We administered the surveys in 2016 (before certification launch) and 2021 (after certification launch) to answer the following questions: Was certification associated with positive outcomes among CHWs after its launch? Did harmful shifts occur among the CHW workforce and employers after certification launch? Was certification associated with disparities among CHWs after its launch? RESULTS: Certification was associated with higher pay among certified (vs noncertified) CHWs, better perceptions of CHWs among certified (vs noncertified) CHWs, and better integration of certified (vs noncertified) CHWs into care teams. We found no adverse shifts in CHW workforce by sociodemographic variables or in CHW employer characteristics (most notably CHW employer hiring requirements) after certification launch. After certification launch, certified and uncertified CHWs had similar demographic and educational characteristics. However, certified CHWs more often worked in large, clinical organizations while uncertified CHWs most often worked in medium-sized community-based organizations. CONCLUSIONS: Our evaluation of Massachusetts CHW certification suggests that CHW certification was not associated with workforce disparities and was associated with positive outcomes. Our study fills a notable gap in the research literature and can guide CHW research agendas, certification efforts in Massachusetts and other states, and program efforts to champion this critical, grassroots workforce.

Effects of a Cool-Down after Supramaximal Interval Exercise on Autonomic Modulation.

Supramaximal interval exercise alters measures of autonomic modulation, while a cool-down may speed the recovery of vagal modulation. The purpose of this study was to compare the effects of a cool-down (pedaling a cycle ergometer at 50 rpm against a resistance of 45 W) versus passive recovery (no pedaling) after supramaximal interval exercise on autonomic modulation. Sixteen moderately active individuals (Mean ± SD: 23 ± 3 years (men: n = 10; women: n = 6) were assessed for autonomic modulation at Rest, and 15 (R15), 30 (R30), 45 (R45) and 60 (R60) min following supramaximal interval exercise. Linear measures of autonomic modulation included natural log (ln) total power (lnTP), high-frequency power (lnHF), the ratio of low frequency (LF) to HF ln(LF/HF) ratio, root mean square of successive differences between normal heartbeats (lnRMSSD), while non-linear measures included sample entropy (SampEn) and Lempel-Ziv entropy (LZEn). Two-way repeated ANOVAs were used to evaluate the main effects of condition (cool-down, passive recovery) across time (Rest, and R15, R30, R45 and R60). There were significant (p ≤ 0.05) condition by time interactions for SampEn and LZEn, such that they decreased at 15, 30, 45 and 60 min during passive recovery compared to Rest, with the recovery of SampEn and LZEn by 60 and 45 min, respectively, during cool-down. There were significant (p ≤ 0.05) main effects of time for lnTP, lnHF and lnRMSSD, such that lnTP, lnHF and lnRMSSD were attenuated, and lnLF/HF ratio was augmented, at all recovery times compared to Rest. These data demonstrate that a cool-down increases the recovery of nonlinear measures of vagal modulation within 45-60 min after supramaximal interval exercise, compared to passive recovery in moderately active individuals.

Cardiac Autonomic Function Following Bilateral and Unilateral Upper Body Acute Resistance Exercise.

The purpose of this study was to compare cardiac autonomic responses following bilateral and unilateral upper-body (UB) acute resistance exercise (ARE). In total, 14 individuals were assessed for markers of cardiac autonomic responses via heart rate variability (HRV) and baroreflex sensitivity (BRS) at rest and at 10- and 30-min following ARE. Logarithmically transformed (ln) HRV measures included: total power (ln TP), high-frequency power (ln HF power), low-frequency power (ln LF power), sympathovagal balance (ln LF: HF), and the square root of the mean squared differences of successive R-R intervals (ln RMSSD). BRS was assessed using the sequence method. Two-way repeated measures ANOVAs were used to analyze effects of UB ARE (bilateral, unilateral) across time (Rest, 10, and 30 min). There were no significant (p > 0.05) interactions. However, there were significant (p ≤ 0.05) main effects of time such that ln TP, ln HF power, ln RMSSD, and BRS decreased and did not recover within 30 min compared to Rest for both conditions. Collectively, this study suggests that bilateral and unilateral UB ARE yielded similar reductions, for at least 30 min, in respect to vagal measures of HRV and BRS.

Hemodynamic response and pulse wave analysis after upper- and lower-body resistance exercise with and without blood flow restriction.

Resistance exercise (RE) has been shown to elevate hemodynamics and pulse wave reflection. However, the effects of acute RE with blood flow restriction (BFR) on hemodynamics and pulse wave reflection are unclear. The purpose of this study was to evaluate the differences between upper- and lower-body RE with and without BFR on hemodynamics and pulse wave reflection. Twenty-three young resistance-trained individuals volunteered for the study. Hemodynamics and pulse wave reflection were assessed at rest, 10, 25, 40, and 55 min after either upper- or lower-body with or without BFR. The upper-body RE (URE) consisted of the latissimus dorsi pulldown and chest press; the lower-body RE (LRE) consisted of knee extension and knee flexion. The BFR condition consisted of four sets of 30, 15, 15, and 15 repetitions at 30% 1-repetition maximum (1RM) while the without BFR condition consisted of four sets of 8 repetitions at 70% 1RM. Heart rate, rate pressure product, and subendocardial viability ratio significantly (p < 0.05) increased after all exercises. Brachial and aortic systolic blood pressure (BP) significantly (p < 0.05) elevated after LRE while brachial and aortic diastolic BP significantly (p < 0.05) reduced after URE. Augmentation pressure, augmentation index (AIx), AIx normalized at 75 bpm, and wasted left ventricular pressure energy significantly (p < 0.05) increased after URE while transit time of reflected wave significantly (p < 0.05) decreased after LRE. URE places greater stress on pulse wave reflection while LRE results in greater responses in BP. Regardless of URE or LRE, the cardiovascular responses between BFR and without BFR are similar.HIGHLIGHTS High-load resistance exercise and low-load resistance exercise with blood flow restriction may produce similar cardiovascular responses.Upper-body resistance exercise generates greater changes on pulse wave reflections while lower-body resistance exercise induces greater elevations in systolic blood pressure.

Evaluating the impact of community health worker certification in Massachusetts: Design, methods, and anticipated results of the Massachusetts community health worker workforce survey.

Background: Professional certification of community health workers (CHWs) is a debated topic. Although intended to promote CHWs, certification may have unintended impacts given the grassroots nature of the workforce. As such, both intended effects and unintended adverse effects should be carefully evaluated. However, there is a lack of published literature describing such effective evaluations with a robust methodology. In this methods paper, we describe a key component of evaluating CHW certification in Massachusetts-the Massachusetts CHW Workforce Survey. Methods: Design of the surveys was informed by a program theory framework that delineated both positive and negative potential impacts of Massachusetts CHW certification on CHWs and CHW employers. Using this framework, we developed measures of interest and preliminary CHW and CHW employer surveys. To validate and refine the surveys, we conducted cognitive interviews with CHWs and CHW employers. We then finalized survey tools with input from state and national stakeholders, CHWs, and CHW employers. Our sample consisted of three frames based on where CHWs are most likely to be employed in Massachusetts: acute care hospitals, community-based organizations, and ambulatory care health centers, primarily community health centers and federally qualified health centers. We then undertook extensive outreach efforts to determine whether each organization employed CHWs and to obtain CHW and CHW employer contact information. Our statistical analysis of the data utilized inverse probability score weighting accounting for organizational, site, and individual response. Anticipated results: Wave one of the survey was administered in 2016 prior to launch of Massachusetts CHW certification and wave two in 2021. We report descriptive statistics of the three sample frames and response rates of each survey for each wave. Further, we describe select anticipated results related to certification, including outcomes of the program theory framework. Conclusions: The Massachusetts CHW Workforce Survey is the culmination of 5 years of effort to evaluate the impact of CHW certification in Massachusetts. Our comprehensive description of our methodology addresses an important gap in CHW research literature. The rigorous design, administration, and analysis of our surveys ensure our findings are robust, valid, and replicable, which can be leveraged by others evaluating the CHW workforce.

Free-weight versus weight machine resistance exercise on pulse wave reflection and aortic stiffness in resistance-trained individuals.

The purpose of this study was to compare the vascular responses to acute free-weight (FW) resistance exercise (RE) versus weight machines (WM). Thirty-two resistance-trained individuals participated in this study. Both modalities involved performing acute RE and a control. Blood pressure and measures of pulse wave reflection were assessed using pulse wave analysis. Aortic stiffness was assessed using carotid-femoral pulse wave velocity (cf-PWV). A repeated measures analysis of variance was used to determine the effects of modality (FW and WM) and condition (acute RE and control) across time (rest and 10-20 min after exercise) on measures of pulse wave reflection and aortic stiffness. Significance was set a priori at p ≤ 0.05. There were no modality by condition by time interactions for any variable, such that the FW and WM modalities responded similarly across time after acute RE (p > 0.05). There were significant (p ≤ 0.05) increases in heart rate, aortic systolic blood pressure, aortic pulse pressure, augmentation index normalized at 75bpm, and decreases in subendocardial viability ratio (SEVR) after acute RE, compared to rest. There was also a significant (p ≤ 0.05) increase in cf-PWV after acute RE, compared to rest. In conclusion, this study demonstrates that acute free-weight and weight-machine RE are associated with transient increases in measures of pulse wave reflection and aortic stiffness, with reductions in myocardial perfusion. These data demonstrate that both modalities result in significant stress on the myocardium during recovery, while simultaneously increasing pressure on the aorta for at least 10-20 min.

The Effects of Machine-Weight and Free-Weight Resistance Exercise on Hemodynamics and Vascular Function.

The purpose of this study was to examine hemodynamic and vascular responses between machine-weight and free-weight exercise. Resistance-trained individuals were assigned to a machine-weight (n = 13) or free-weight (n = 15) group. Groups completed two visits consisting of their assigned exercise condition and a control (CON). A 2 × 2 × 3 repeated measures ANOVA was used to test the effects of group across condition and time on the hemodynamic parameters [cardiac output (CO), heart rate (HR), total peripheral resistance (TPR), mean arterial pressure (MAP), and stroke volume (SV)]. A 2 × 2 × 2 repeated measures ANOVA was used to test the effects of group across condition and time on the hemodynamic variable, forearm vascular conductance (FVC), as well as on vascular measures [forearm blood flow (FBF), blood flow peak, and total reactive hyperemia (RH)]. Main effects were analyzed using pairwise comparisons. The results of the present study demonstrate that both machine-weight and free-weight exercise produce similar (p > 0.05) alterations in hemodynamics and vascular function. Specifically, during recovery both groups demonstrated significant (p ≤ 0.05) increases in measures of hemodynamics such as CO, HR and FVC, as well as significant (p ≤ 0.05) decreases in TPR, MAP, and SV. Measures of vascular function such as FBF, blood flow peak, and total RH were also significantly (p ≤ 0.05) increased during recovery. Therefore, this study suggests that either machine weight or free-weight exercise may induce acute hemodynamic and vascular benefits, which may reduce the risk of cardiovascular disease (CVD) and CVD events.

High Availability of the α7-Nicotinic Acetylcholine Receptor in Brains of Individuals with Mild Cognitive Impairment: A Pilot Study Using 18F-ASEM PET.

Emerging evidence supports a hypothesized role for the α7-nicotinic acetylcholine receptor (α7-nAChR) in the pathophysiology of Alzheimer's disease. 18F-ASEM (3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-6-18F-fluorodibenzo[b,d]thiophene 5,5-dioxide) is a radioligand for estimating the availability of α7-nAChR in the brain in vivo with PET. Methods: In this cross-sectional study, 14 patients with mild cognitive impairment (MCI), a prodromal stage to dementia, and 17 cognitively intact, elderly controls completed 18F-ASEM PET. For each participant, binding in each region of interest was estimated using Logan graphical analysis with a metabolite-corrected arterial input function. Results: Higher 18F-ASEM binding was observed in MCI patients than in controls across all regions, supporting higher availability of α7-nAChR in MCI. 18F-ASEM binding was not associated with verbal memory in this small MCI sample. Conclusion: These data support use of 18F-ASEM PET to examine further the relationship between α7-nAChR availability and MCI.

Pulse wave reflection responses to bench press with and without practical blood flow restriction.

Resistance exercise is recommended to increase muscular strength but may also increase pulse wave reflection. The effect of resistance exercise combined with practical blood flow restriction (pBFR) on pulse wave reflection is unknown. The purpose of this study was to evaluate the differences in pulse wave reflection characteristics between bench press with pBFR and traditional high-load bench press in resistance-trained men. Sixteen resistance-trained men participated in the study. Pulse wave reflection characteristics were assessed before and after low-load bench press with pBFR (LL-pBFR), traditional high-load bench press (HL), and a control (CON). A repeated-measures ANOVA was used to evaluate differences in pulse wave reflection characteristics among the conditions across time. There were significant (p ≤ 0.05) interactions for heart rate, augmentation index, augmentation index normalized at 75 bpm, augmentation pressure, time-tension index, and wasted left ventricular energy such that they were increased after LL-pBFR and HL compared with rest and CON, with no differences between LL-pBFR and HL. Aortic pulse pressure (p < 0.001) was elevated only after LL-pBFR compared with rest. In addition, there was a significant (p ≤ 0.05) interaction for aortic diastolic blood pressure (BP) such that it was decreased after LL-pBFR compared with rest and CON but not HL. The subendocardial viability ratio and diastolic pressure-time index were significantly different between LL-pBFR and HL compared with rest and CON. There were no significant interactions for brachial systolic or diastolic BP, aortic systolic BP, or time of the reflected wave. In conclusion, acute bench press resistance exercise significantly altered pulse wave reflection characteristics without differences between LL-pBFR and HL.

Autonomic modulation and baroreflex sensitivity after acute resistance exercise: responses between sexes.

BACKGROUND: The aim of this study was to evaluate autonomic modulation, blood pressure variability and baroreflex sensitivity (BRS) responses to an acute bout of free-weight resistance exercise in resistance-trained men (N.=14) and women (N.=13). METHODS: Participants underwent both an acute bout of resistance exercise (RE) consisting of 3 sets of 10 repetitions at 75% 1-repetition maximum on the squat, bench press, and deadlift, and a quiet control. Autonomic modulation, blood pressure variability (LFSAP), and cardiovagal BRS were assessed at rest, 15-20 minutes (Rec1) and 25-30 minutes (Rec2) postexercise. Log transformed measures of autonomic modulation included root square of the mean ssquared differences of successive RR intervals (LnRMSSD), high-frequency power (LnHFRR) and low-frequency power (LnLFRR) and sympathovagal balance (LnLFRR/HFRR). LFSAP was used as a measurement of vasomotor tone. Cardiovagal BRS was assessed using the sequence method. RESULTS: There were no significant sex differences at rest and no significant sex by time by condition interactions for any variable. Compared with rest there were augmentations in LnLFRR/HFRR (P=0.002) and LFSAP (P=0.001) at Rec1 and Rec2. RMSSD and cardiovagal BRS were significantly (P=0.0001) decreased at Rec1 and Rec2 compared to rest after the acute RE. CONCLUSIONS: Both sexes demonstrated that acute resistance exercise using free weights has a profound impact on autonomic modulation, blood pressure variability and cardiovagal BRS.