Oxygen pulse best predicts energy expenditure during stair ascent and descent in individuals with chronic stroke.

BACKGROUND: To determine whether minute ventilation-to-carbon dioxide production (VE/VCO2), oxygen pulse (VO2/HR), and rate pressure product (RPP: VO2 * HR/1000) can explain energy expenditure during stair ascent/descent and whether energy expenditure during stair ascent/descent can discriminate between walking abilities in individuals with chronic stroke. MATERIALS AND METHODS: Regression analysis of cross-sectional data from 50 individuals between 1 and 4 years post-stroke was carried out to investigate the prediction of energy expenditure during stair ascent/descent. In addition, discriminant analysis was carried out to investigate the discrimination between walking abilities for energy expenditure: community (walking speed ≥ 0.8 m/s) and non-community (walking speed < 0.8 m/s) walkers. RESULTS: Oxygen pulse and rate pressure product were retained in the model. Oxygen pulse alone explained 70% of the variance in energy expenditure during stair ascent/descent. By adding rate pressure product, 79% of the variance was explained. Energy expenditure was able to discriminate the community from the non-community walkers, with a cutoff value of 13.8 ml∙kg-1∙min-1 and correctly classified 62% of the non-community and 78% of the community walkers. CONCLUSION: Oxygen pulse and rate pressure product significantly predicted energy expenditure during stair ascent/descent in individuals with chronic stroke. Energy expenditure during stair ascent/descent discriminated community from non-community walkers.

Exercise Training Reduces Inflammation and Fibrosis and Preserves Myocardial Function and Perfusion in a Model of Chronic Chagas Cardiomyopathy. / Treinamento Físico Reduz a Inflamação e a Fibrose e Preserva a Função e a Perfusão Miocárdica em um Modelo de Cardiomiopatia Chagásica Crônica.

BACKGROUND: Chronic Chagas cardiomyopathy (CCC) is caused by an inflammatory process induced by Trypanosoma cruzi, which leads to myocarditis with reactive and reparative fibrosis. CCC progresses with myocardial perfusion abnormalities and histopathological events that affect cardiorespiratory fitness (CRF). OBJECTIVES: We evaluated the effects of aerobic physical training (APT) on myocardial perfusion and on morphological and functional impairments related with inflammation and fibrosis in Syrian hamsters with CCC. As a secondary objective, we analyzed the cross-sectional areas of the skeletal muscle. METHODS: Hamsters with CCC and their respective controls were divided into four groups: CCC sedentary, CCC-APT, sedentary control and APT control. Seven months after infection, the animals underwent echocardiography, myocardial perfusion scintigraphy and cardiopulmonary exercise testing. Moderate-intensity APT was performed for fifty minutes, five times a week, for eight weeks. Subsequently, the animals were reassessed. Histopathological analysis was conducted after the above-mentioned procedures. The level of significance was set at 5% in all analyses (p<0.05). RESULTS: CCC sedentary animals presented worse myocardial perfusion defects (MPD) over time, reduced left ventricle ejection fraction (LVEF) and showed more inflammation and fibrosis when compared to other groups (mixed ANOVA analysis). Conversely, APT was able to mitigate the progression of MPD, ameliorate inflammation and fibrosis and improve CRF efficiency in CCC-APT animals. CONCLUSIONS: Our study demonstrated that APT ameliorated cardiac dysfunction, MPD, and reduced inflammation and fibrosis in CCC hamster models. Additionally, CCC-SED animals presented skeletal muscle atrophy while CCC-APT animals showed preserved skeletal muscle CSA. Understanding APT's effects on CCC's pathophysiological dimensions is crucial for future research and therapeutic interventions.

FUNDAMENTO: A Cardiomiopatia Chagásica Crônica (CCC) é causada por um processo inflamatório induzido pelo Trypanosoma cruzi, que leva à miocardite com fibrose reativa e reparativa. A CCC progride com alterações de perfusão miocárdica e eventos histopatológicos que afetam a Aptidão Cardiorrespiratória (ACR). OBJETIVOS: Avaliamos os efeitos do Treinamento Físico Aeróbico (TFA) na perfusão miocárdica e nos comprometimentos morfológicos e funcionais relacionados à inflamação e fibrose em hamsters sírios com CCC. Como objetivo secundário, analisamos as áreas de secção transversa do músculo esquelético. MÉTODOS: Hamsters com CCC e seus respectivos controles foram divididos em quatro grupos: CCC sedentário, CCC-TFA, controle sedentário e controle TFA. Sete meses após a infecção, os animais foram submetidos à ecocardiografia, à cintilografia de perfusão miocárdica e ao teste de esforço cardiopulmonar. TFA de intensidade moderada foi realizado durante cinquenta minutos, cinco vezes por semana, por oito semanas. Posteriormente, os animais foram reavaliados. A análise histopatológica foi realizada após os procedimentos acima mencionados. O nível de significância foi estabelecido em 5% em todas as análises (p<0,05). RESULTADOS: Animais com CCC sedentários apresentaram piores Defeitos de Perfusão Miocárdica (DPM) ao longo do tempo, Fração de Ejeção do Ventrículo Esquerdo (FEVE) reduzida, e apresentaram mais inflamação e fibrose quando comparados aos demais grupos (análise ANOVA mista). Por outro lado, o TFA foi capaz de mitigar a progressão do DPM, atenuar a inflamação e a fibrose e melhorar a eficiência da ACR em animais CCC-TFA. CONCLUSÃO: Nosso estudo demonstrou que o TFA melhorou a disfunção cardíaca, DPM e reduziu a inflamação e a fibrose em modelos de hamster com CCC. Além disso, os animais CCC-SED apresentaram atrofia do músculo esquelético, enquanto os animais CCC-TFA apresentaram a AST do músculo esquelético preservada. Compreender os efeitos da TFA nas dimensões fisiopatológicas da CCC é crucial para futuras pesquisas e intervenções terapêuticas.

Reference values for triceps surae tissue oxygen saturation by near-infrared spectroscopy.

Objective.To establish the reference values for peripheral tissue perfusion of the triceps surae muscle assessed by Near-infrared spectroscopy (NIRS) at rest and in progressive effort.Approach.A total of 288 apparently healthy individuals of both sexes were included; between 30 and 79 years of age; nonsmokers; without diagnosis of diabetes mellitus, systemic arterial hypertension, kidney disease, symptoms of angina and intermittent claudication, or any musculoskeletal alteration that would prevent physical exertion; and without diagnosis of Peripheral arterial disease (PAD) or other associated symptoms. All individuals performed anthropometric measurements, physical activity levels, and tissue oxygen saturation (StO2) assessments by NIRS during and after arterial occlusion maneuver and incremental shuttle walking test. The variables obtained by NIRS were presented in percentiles (P) for general comparison between sexes and for comparison between sexes according to age group. The relationship between the NIRS data and other variables was tested.Main results.Considering P50 and p<0.05, men had lower StO2 values, higher deoxygenation and reoxygenation (Tx-reox) rates at rest, and higher Tx-reox during progressive effort. There were correlations (p<0.0001) of body composition with the lowest StO2 and Tx-reox values and of functional capacity with Tx-reox in occlusion and Tx-reox.Significance.The percentiles presented can clinically assist in the diagnosis and monitoring of different health conditions; however, it is important to consider the individual's sex, body composition, and functional capacity.

Evaluation of the Glittre-ADL test as an instrument for classifying functional capacity of individuals with cardiovascular diseases.

BACKGROUND: The assessment of functional capacity in individuals with cardiovascular disease is closely related to lower limb function. The Glittre-ADL test is a global test to evaluate this patients. OBJECTIVE: We aimed to verify whether the Glittre-ADL test discriminates functional status while evaluating individuals with cardiovascular disease. METHODS: A total of 42 participants were evaluated using the Glittre-ADL test Incremental Shuttle Walking Test (shuttle test), Human Activity Profile, and Duke Activity Status Index. Data from the shuttle test, Human Activity Profile, and DASI were divided into tertiles for statistical analysis. The time required to complete the Glittre-ADL test was compared among tertiles of the shuttle test, Duke Activity Status Index and Human Activity Profile using analysis of variance. RESULTS: There were significant differences between the tertiles of the shuttle test. Tertile 1 was different from tertiles 2 (mean difference, 47.63; 95% CI, 19.86-75.39) and 3 (mean difference, 67.15; 95% CI, 41.25-93.05). For the Duke Activity Status Index there were significant between-group differences. Tertile 1 was different from tertiles 2 (mean difference, 42.45; 95% CI, 8.82-76.09) and 3 (mean difference, 43.56; 95% CI, 13.68-73.44). For the Human Activity Profile there were significant between-group differences. Tertile 3 was different from tertiles 1 (mean difference, 51.46; 95% CI, 21.27-81.64) and 2 (mean difference, 33.01; 95% CI, 3.52-62.51). CONCLUSION: The Glittre-ADL test is able to discriminate the functional status in individuals with cardiovascular disease, most of whom have hypertension. The Glittre-ADL test was sensitive to discriminate more functionally affected individuals.

Could peak oxygen uptake be estimated from proposed equations based on the six-minute walk test in chronic heart failure subjects?

OBJECTIVES: To evaluate the agreement between the measured peak oxygen uptake (VO2peak) and the VO2peak estimated by four prediction equations based on the six-minute walk test (6MWT) in chronic heart failure patients. METHOD: Thirty-six chronic heart failure patients underwent cardiopulmonary exercise testing and the 6MWT to assess their VO2peak. Four previously published equations that include the variable six-minute walk distance were used to estimate the VO2peak: Cahalin, 1996a (1); Cahalin, 1996b (2); Ross, 2010 (3); and Adedoyin, 2010 (4). The agreement between the VO2peak in the cardiopulmonary exercise testing and the estimated values was assessed using the Bland-Altman method. A p-value of <0.05 was considered statistically significant. RESULTS: All estimated VO2peak values presented moderate correlation (ranging from 0.55 to 0.70; p<0.001) with measured VO2peak values. Equations 2, 3, and 4 underestimated the VO2peak by 30%, 15.2%, and 51.2%, respectively, showing significant differences from the actual VO2peak measured in the cardiopulmonary exercise testing (p<0.0001 for all), and the limits of agreement were elevated. The VO2peak estimated by equation 1 was similar to that measured by the cardiopulmonary exercise testing, and despite the agreement, bias increased as VO2peak increased. CONCLUSIONS: Only equation 1 showed estimated VO2peak similar to the measured VO2peak; however, a large limits of agreement range (∼3 METs) does not allow its use to estimate maximal VO2peak.

Assessment of intensity effort of middle-aged adults practicing regular walking.

BACKGROUND: Walking is one of the most commonly recommended activities for sedentary individuals. When performed at the correct intensity, it can provide cardiovascular, respiratory, metabolic, and other benefits by providing a training effect in addition to reducing the risk of death from cardiovascular diseases and other chronic health conditions. OBJECTIVES: The primary aim of this study was to assess whether individuals who practiced regular unsupervised walking carry out the activity safely and with sufficient effort intensity parameters to have a positive physiological (training) effect. The secondary objective was to compare the training heart rate (HR) and the stability of the HR within the ideal range of training between the sexes. METHOD: Individuals were selected from walking tracks within the city of Belo Horizonte, Brazil. The study included subjects from 40 to 60 years of age who had practiced walking for at least two months prior to the study, walking at least three times a week. Individuals who agreed to participate in the survey were asked to walk 15 minutes at their usual pace with their HR measured every 5 minutes using a heart rate monitor. Their average walking HR was compared to the average training HR based on the formula: (220 - age) × 70 to 80% that would result in a positive physiological training effect. RESULTS: Of the 142 individuals evaluated, 25.4% achieved the average training HR. This result was significantly lower than those who did not achieve the average training HR while walking (p=0.002). There were significant differences between men and women who had reached the training HR (p=0.0001). CONCLUSION: The authors found that individuals who walk regularly performed outside the range of the ideal HR intensity that would cause a positive physiological effect and therefore would probably not achieve a beneficial training effect while walking.

Optoelectronic plethysmography: intra-rater and inter-rater reliability in healthy subjects.

Optoelectronic plethysmography (OEP) has been used to measure changes in chest wall volume and its compartments. However, literature lacks research on its reliability. The purpose of this study was to evaluate the intra-rater and inter-rater reliability of OEP. Thirty-two healthy subjects were evaluated at rest and during submaximal exercise on a cycle ergometer. The following variables were assessed: chest wall volume (VCW); percentage contribution of the pulmonary rib cage (V(rcp)%), abdominal rib cage (V(rca)%), rib cage (V(rc)%) and abdomen (Vab%); chest wall end-expiratory volume (Vee(cw)); chest wall end-inspiratory volume (Vei(cw)); ratio of inspiratory time to total time of the respiratory cycle (Ti/T(tot)); respiratory rate (f) and mean inspiratory flow (V(cw)/Ti). Intraclass correlation coefficient (ICC) and coefficient of variation of Method Error (CV(ME)) were used to evaluate reliability. Results showed ICC values higher than 0.75 and CV(ME) values less than 10% for most variables at rest and during exercise indicating that OEP is a reliable instrument to assess chest wall volumes at rest and during exercise in healthy subjects.

Interaction between cytokine gene polymorphisms and the effect of physical exercise on clinical and inflammatory parameters in older women: study protocol for a randomized controlled trial.

BACKGROUND: Aging is associated with chronic low-grade inflammatory activity with an elevation of cytokine levels. An association between regular physical activity and reduction of blood levels of anti-inflammatory cytokines is demonstrated in the literature pointing to an anti-inflammatory effect related to exercise. However, there is no consensus regarding which type of exercise and which parameters are the most appropriate to influence inflammatory markers. Evidence indicates that the single nucleotide polymorphism (SNP) can influence the synthesis of those cytokines affecting their production. METHODS/DESIGN: The design of this study is a randomized controlled trial. The aim of this study is to investigate the interaction between the cytokine genes SNP and the effect of physical activity on older women. The main outcomes are: serum levels of sTNFR-1, sTNFR-2, interleukin (IL)-6, IL-10, measured by the ELISA method; genotyping of tumor necrosis factor- (TNF)-alpha (rs1800629), IL6 (rs1800795), IL10 (rs1800896) by the TaqMan Method (Applied Biosystems, Foster City, CA, USA); and physical performance assessed by Timed Up and Go and 10-Meter Walk Tests. Secondary outcomes include: Geriatric Depression Scale, Perceived Stress Scaleand aerobic capacity, assessed by the six-minute walk; and lower limb muscle strength, using an isokinetic dinamometer (Biodex Medical Systems, Inc., Shirley, NY,USA). Both exercise protocols will be performed three times a week for 10 weeks, 30 sessions in total. DISCUSSION: Investigating the interaction between genetic factors and exercise effects of both protocols of exercise on the levels of inflammatory cytokine levels can contribute to guide clinical practice related to treatment and prevention of functional changes due to chronic inflammatory activity in older adults. This approach could develop new perspectives on preventive and treatment proposals in physical therapy and in the management of the older patient. TRIAL REGISTRATION: (ReBEC) RBR9v9cwf.

Assessment of intensity effort of middle-aged adults practicing regular walking

Background: Walking is one of the most commonly recommended activities for sedentary individuals. When performed at the correct intensity, it can provide cardiovascular, respiratory, metabolic, and other benefits by providing a training effect in addition to reducing the risk of death from cardiovascular diseases and other chronic health conditions. Objectives: The primary aim of this study was to assess whether individuals who practiced regular unsupervised walking carry out the activity safely and with sufficient effort intensity parameters to have a positive physiological (training) effect. The secondary objective was to compare the training heart rate (HR) and the stability of the HR within the ideal range of training between the sexes. Method: Individuals were selected from walking tracks within the city of Belo Horizonte, Brazil. The study included subjects from 40 to 60 years of age who had practiced walking for at least two months prior to the study, walking at least three times a week. Individuals who agreed to participate in the survey were asked to walk 15 minutes at their usual pace with their HR measured every 5 minutes using a heart rate monitor. Their average walking HR was compared to the average training HR based on the formula: (220 - age) × 70 to 80% that would result in a positive physiological training effect. Results: Of the 142 individuals evaluated, 25.4% achieved the average training HR. This result was significantly lower than those who did not achieve the average training HR while walking (p=0.002). There were significant differences between men and women who had reached the training HR (p=0.0001). Conclusion: The authors found that individuals who walk regularly performed outside the range of the ideal HR intensity that would cause a positive physiological effect and therefore would probably not achieve a beneficial training effect while walking.