Preliminary Effects of a Structured Educational Program in Cardiac Patients at Different Stages of Enrollment in Cardiovascular Rehabilitation.

This quasi-experimental study investigated the preliminary effects of a structured education intervention in a pooled sample of cardiovascular rehabilitation (CR) patients in Brazil. Recently enrolled (RE) and long-term enrolled (LTE) patients attended 12 weekly education sessions in addition to three weekly exercise sessions. Patients completed surveys assessing disease-related knowledge, physical activity, food intake, self-efficacy, and health literacy. Functional capacity was assessed by the 6-minutes walking test. All outcomes were assessed at pre-,post-CR, and 6-months follow-up. Bonferroni correction was applied. In total, 69 (69.7%) patients completed all three assessments. There were significant improvements in knowledge pre-to post-test in both subgroups (p < 0.001), and in functional capacity (p ≤ 0.001) and food intake (p ≤ 0.001) pre-to post-test in the RE subgroup. Post-test knowledge was correlated to physical activity, functional capacity and health literacy. This preliminary study suggests the importance of structured education for CR patients. A larger study using a randomized controlled design is needed to determine efficacy.

Prescrição de Exercício Aeróbio na Reabilitação Cardíaca Baseada na Frequência Cardíaca dos Estágios do Teste da Fala e do Teste de Caminhada de 6 Minutos / Aerobic Exercise Prescription in Cardiac Rehabilitation Based on Heart Rate from Talk Test Stages and 6-Minute Walk Test

Resumo Fundamento Embora o Teste da Fala (TF) seja um teste confiável e de baixo custo, seu uso para prescrição de exercício aeróbio ainda é limitado. Objetivo Analisar a frequência cardíaca (FC) dos estágios do TF e no pico do teste de caminhada de 6 minutos (TC6min) como parâmetro para a prescrição de exercício aeróbio comparando com a FC no primeiro e segundo limiares ventilatórios (LV1 e LV2) do teste cardiopulmonar de exercício (TCPE). Métodos Pacientes com doença cardiovascular compareceram a 3 dias de avaliação: 1) anamnese e TCPE; 2) TC6min; e 3) TF. Foram usados ANOVA unidirecional de medidas repetidas ou teste de Friedman para comparar a FC no LV1 e LV2 com a FC nos estágios do TF: último positivo (TF+), primeiro equívoco (TF±) e negativo (TF−) e no pico do TC6min. O teste de Pearson ou Spearman avaliou se há correlação entre FC em LVs, estágios do TF e TC6min. A significância estatística foi fixada em 5%. Resultados O estudo incluiu 22 pacientes cardíacos (13 homens, 61 ± 8 anos). A FC no LV1 foi semelhante à FC no TF+ (p = 0,987) e TF± (p = 0,154), e moderadamente correlacionada com o TF+ (r = 0,479, p = 0,024). A FC no LV2 foi semelhante ao TF− (p = 0,383), com forte correlação (r = 0,757, p < 0,001). A FC no pico do TC6min foi significativamente diferente da FC no TF+, TF± e LV1 (p = 0,001, p = 0,005 e p < 0,001, respectivamente), mas semelhante ao TF− (p = 0,68). Conclusões A FC no TF+ e TF− reflete a FC no LV1 e LV2, respectivamente, diferentemente do TC6min, que foi semelhante apenas ao LV2. O TF pode ser um teste objetivo para auxiliar a prescrição de exercício aeróbio na reabilitação cardíaca.

Abstract Background Although the Talk Test (TT) is a reliable and low-cost test, its use for aerobic exercise prescription is still limited. Objective To analyze the heart rate (HR) in the stages of the TT and at the peak of the 6-minute walk test (6MWT) as a parameter to prescribe aerobic exercise compared with HR at the first and second ventilatory thresholds (VT1 and VT2) of cardiopulmonary exercise test (CPET). Methods Individuals with cardiovascular disease attended three assessment days: 1) anamnesis and CPET; 2) 6MWT; and 3) TT. One-way repeated measures ANOVA or Friedman's test were used to compare HR at VT1 and VT2 with HR at TT stages: last positive (TT+), first equivocal (TT±), and negative (TT−), and at the peak of the 6MWT. Pearson's or Spearman's test assessed correlations between HR at VTs, TT stages, and 6MWT. Statistical significance was set at 5%. Results The study included 22 cardiac patients (13 men, 61 ± 8 years). HR at VT1 was similar to HR at TT+ (p = 0.987) and TT± (p = 0.154), and moderately correlated with TT+ (r = 0.479, p = 0.024). HR at VT2 was similar to TT− (p = 0.383), with a strong correlation (r = 0.757, p < 0.001). HR at the peak of the 6MWT was significantly different from HR at TT+, TT±, and VT1 (p = 0.001, p = 0.005, and p < 0.001, respectively) but similar to TT− (p = 0.68). Conclusions HR at TT+ and TT− reflect HR at VT1 and VT2, respectively, differently from 6MWT, which was similar only to VT2. TT may be an objective test to assist aerobic exercise prescription in cardiac rehabilitation.

Impacto da COVID-19 nos Programas de Reabilitação Cardiovascular no Brasil: Um Estudo Transversal Baseado em uma Pesquisa Online / Impact of COVID-19's on Cardiovascular Rehabilitation Programs in Brazil: An Online Survey-Based Cross-Sectional Study

Resumo Fundamento A pandemia da COVID-19 teve um impacto sobre os programas de reabilitação cardiovasculares (RC) no Brasil. Objetivos Descrever características dos programas de RC no Brasil, os impactos da primeira onda epidemiológica da COVID-19 (primeiros 60 dias) sobre os programas, e apresentar as iniciativas usadas para superar esses impactos. Métodos Este estudo transversal e retrospectivo usou um questionário online específico. Os participantes eram coordenadores de programas de RC. As variáveis foram apresentadas por região geográfica do Brasil, como as seguintes categorias: característica demográficas, clínicas e operacionais. O nível de significância estatística foi definido em 5%. Resultados Cinquenta e nove programas de RC atendiam 5349 pacientes, dos quais somente 1817 eram pacientes após eventos cardiovasculares agudos, o que correspondia a 1,99% dos pacientes internados no mês anterior à pesquisa (n=91.231). O maior impacto foi a suspensão das atividades presenciais, o que ocorreu de maneira similar em áreas com as taxas mais altas e áreas com as taxas mais baixas de COVID-19 no período. Quarenta e quatro (75%) programas foram interrompidos de forma breve, e três (5%) foram encerrados. Todos os 42 programas que já utilizavam estratégias de reabilitação remota notaram aumento substancial nas atividades, baseadas principalmente no uso da mídia e chamadas por vídeo. Somente três (5%) consideraram seguro atender pacientes durante os primeiros 60 dias. Conclusões Houve redução no número de programas de RC devido a pandemia da COVID-19. Atividades de telerreabilitação aumentaram durante os primeiros dois meses da pandemia da COVID-19, mas que não foi suficiente para superar a redução nas atividades dos programas de RC no Brasil.

Abstract Background The COVID-19 pandemic had an impact on cardiovascular rehabilitation (CR) programs in Brazil. Objectives To describe the characteristics of CR programs in Brazil, the impacts of the first epidemiological wave of COVID-19 (first 60 days) on the programs and present the initiatives used to overcome the impacts. Method This cross-sectional and retrospective study utilized a specific online survey. Participants were coordinators of CR programs. Variables were presented by Brazilian geographic region and as the following categories: demographic, clinical and operational characteristics. The significance level for statistical analysis was set at 5%. Results Fifty-nine CR programs were responsible for 5,349 patients, of which only 1,817 were post-acute cardiovascular events, which corresponded to 1.99% of hospitalized patients in the month prior to the survey (n=91,231). The greatest impact was the suspension of on-site activities, which occurred similarly in areas with the highest and the lowest rates of COVID-19 in the period. Forty-five programs (75%) were shortly interrupted, while three (5%) were ended. All 42 programs that already used remote rehabilitation strategies noticed a substantial increase in activities, based primarily on the use of media and video calling. Only three (5%) considered safe to see patients during the first 60 days. Conclusions There was a reduction in the number of CR programs with the COVID-19 pandemic. Telerehabilitation activities increased during the first two months of the COVID-19 pandemic, but this was not enough to overcome the reduction in CR program activities across Brazil.

Percepções dos Participantes de Reabilitação Cardíaca sobre seus Comportamentos em Saúde e Necessidades de Informação durante a Pandemia COVID-19 no Brasil / Perceptions of Cardiac Rehabilitation Participants Regarding their Health Behaviors and Information Needs during the COVID-19 Pandemic in Brazil

Resumo Fundamento A COVID-19 afetou como as pessoas recebem atendimento de saúde para várias doenças, inclusive doenças cardiovasculares. Objetivos Examinar as percepções dos participantes de reabilitação cardíaca (RC) sobre seus comportamentos em saúde e necessidades de informação durante a pandemia da COVID-19 no Brasil. Métodos Neste estudo transversal, um questionário de 27 itens elaborado pelos investigadores foi administrado online a participantes de dois programas de RC. As perguntas incluíam letramento em saúde (LS; usando a Brief Health Literacy Screening Tool - Breve ferramenta de triagem de letramento em saúde), uso de tecnologia, percepções antes e durante a pandemia da COVID-19, e necessidades de informações. Foram usados coeficiente de correlação de Pearson, testes t pareados e ANOVA, conforme apropriado. Um p <0,05 foi considerado estatisticamente significativo para todos os testes. Resultados No total, 159 (25,5%) participantes de RC responderam ao questionário. Desses, 89,9% tinham LS limitado ou marginal, e 96,2% relataram ter acesso à internet de casa. Os pacientes se preocupam principalmente com a saúde de sua família e própria, além de como o coronavírus é perigoso para sua saúde e como mudou seu estilo de vida. Os participantes perceberam que a qualidade de seus comportamentos em saúde diminuiu significativamente durante a pandemia. A pandemia também mudou as necessidades de informações dos participantes de RC, já que novas necessidades surgiram, tais como, controle de níveis de ansiedade, manter a motivação para levar uma vida saudável durante a pandemia, e como a COVID-19 pode afetar sua condição de saúde. Participantes com LS adequado perceberam significativamente a gravidade da doença e tinham significativamente mais acesso a informações do que os pacientes com LS limitado. Conclusões Nossos resultados destacaram o impacto da pandemia nas percepções dos participantes de RC em relação a seus comportamentos em saúde e necessidades de informação, que podem ser influenciados pelos níveis de LS.

Abstract Background COVID-19 has impacted how people receive health care for many conditions, including cardiovascular diseases. Objectives To examine perceptions of cardiac rehabilitation (CR) participants regarding their health behaviors and information needs during the COVID-19 pandemic in Brazil. Methods In this cross-sectional study, a 27-item questionnaire, developed by the investigators, was administered online to participants from two CR programs. Questions included health literacy (HL; using the Brief Health Literacy Screening Tool), technology use, perceptions before and during the COVID-19 pandemic, and information needs. Pearson correlation coefficients, paired t-tests, and ANOVA were used as appropriate. P < 0.05 was considered statistically significant for all tests. Results Overall, 159 (25.5%) CR participants answered the questionnaire. Of these, 89.9% had limited or marginal HL and 96.2% reported having internet access at home. Patients are mainly concerned about their family's health and their own, as well as how the coronavirus is dangerous to their health and how it has changed their lifestyle. Participants perceived that the quality of their health behaviors significantly decreased during the pandemic. The pandemic also changed information needs of CR participants as new needs emerged, such as the control of anxiety levels, staying motivated to live healthily during a pandemic, and how COVID-19 can impact their health condition. Participants with adequate HL significantly perceived the severity of the disease and having access to information significantly more than those with limited HL. Conclusions Our results highlighted the impact of the pandemic on CR participants' perceptions regarding their health behaviors and information needs, which can be influenced by HL levels.

O desempenho e as respostas fisiológicas ao teste de elevação do calcanhar bipodal são influenciados pela cadência e posição dos tornozelos / Bilateral heel-rise test performance and physiological response are influenced by cadence and ankle position

INTRODUÇÃO: Diferentes protocolos do teste de elevação do calcanhar (TEC) têm sido utilizados, sendo necessário analisar o impacto das variações nas respostas do teste. OBJETIVO: Comparar o desempenho e respostas de oxigenação muscular (OM) e frequência cardíaca (FC) de adultos em diferentes protocolos do TEC bipodal. MATERIAIS E MÉTODOS: Este foi um estudo transversal do tipo cruzado. Trinta participantes (23,1±2,9 anos; 16 homens) realizaram quatro protocolos do TEC bipodal, variando cadenciamento (autocadenciado e cadenciado externamente) e posição dos tornozelos (neutra e dorsiflexão). Para a OM, analisamos a saturação tecidual de oxigênio (StO2 ) e variação da concentração de oxihemoglobina (∆[O2 Hb]) e calculamos a variação entre os menores valores e os valores finais (∆Nadir-Final) e área sob a curva (AUC). Para a FC, calculamos a variação dos valores iniciais e finais (∆FC) e constante de tempo (τ). O teste de Friedman foi utilizado para comparar as variáveis entre os protocolos. A ANOVA de dois fatores foi utilizada para identificar o impacto da cadência e/ou posição dos tornozelos. RESULTADOS: O número de repetições e o tempo de execução foram maiores nos protocolos em posição neutra e cadenciado externamente (p<0,001 para ambos). ∆Nadir-Final (StO2: p<0,001; ∆[O2Hb]: p=0,005) e AUC (StO2: p<0,001; ∆[O2Hb]: p<0,001) dea mbas as variáveis de OM foram maiores nos protocolos em posição neutra. Protocolos autocadenciados apresentaram maior aumento da FC e τ mais rápida (p=0,006 e p=0,046). CONCLUSÃO: O TEC realizado em posição neutra e cadenciamento externo gera maiores repetições e tempo de execução. A dorsiflexão promoveu menor reperfusão muscular e o autocadenciamento, maior e mais rápido aumento da FC.

INTRODUCTION: Different heel-rise test (HRT) protocols have been used, possibly leading to varied responses. It is necessary to analyse the impact of protocol variation on test responses. PURPOSE: To compare the performance, muscle oxygenation (MO), and heart rate (HR) responses of adults in bilateral HRT protocols. METHODS: This was a cross-sectional crossover study. Thirty participants (23.1±2.9 years; 16 men) performed four bilateral HRT protocols with varying cadence (self-cadenced; externally cadenced) and ankle position (neutral; dorsiflexion). For MO responses, we analysed tissue oxygen saturation (StO2) and oxyhemoglobin concentration variation (∆[O2Hb]) and calculated the variation between the smallest and final values (∆Nadir-Final) and the area under the curve (AUC). The variation between the initial and final HR values (∆HR) and the time constant (τ) were calculated. Friedman's test was used to compare the variables among the protocols. Two-way ANOVA was used to identify the impact of cadence and/or ankle position. RESULTS: The number of repetitions and execution time were higher in the neutral position and externally cadenced protocols (p<0.001 for both). ∆Nadir-Final (StO2: p<0.001;∆[O2Hb]: p=0.005) and AUC (StO2: p<0.001; ∆[O2Hb]: p<0.001) of both MO variables were higher in the neutral position protocols. Selfcadenced protocols presented higher HR increase and faster τ (p=0.006 and p=0.046). CONCLUSION: Bilateral HRT performed in a neutral position, and external cadence promotes more repetitions and a longer execution time. Dorsiflexion promotes lower muscle reperfusion, and self-cadence higher and faster HR increase.

Does Hypertension Knowledge Influence Levels of Physical Activity in Hypertensive Patients From a Southern Brazilian Community?

Abstract Background: Increased level of physical activity (PA) and health education are known as non-pharmacological treatments of hypertension (HP). There is a lack of studies investigating the influence of HP knowledge on the level of PA among hypertensive patients. Objective: To examine the influence of patient's knowledge about HP on PA level and the relationship between these variables. Methods: A cross-sectional study was conducted in in a primary care center located in a city in the southern Brazil. A total of 199 hypertensive patients (median 61.2 [13] years; body mass index (BMI) 21.9 (7.5) kg/m2; 72.4% women) were included. The level of PA was assessed by measuring the number of steps taken daily. The knowledge about HP was assessed by a standardized questionnaire (HIPER-Q). The Kruskall-Wallis test was used to compare age, BMI and PA level between HP knowledge categories, and the Spearman test was used to assess correlations (p <0.05). Results: The median score of knowledge about HP for patients categorized as insufficient (n=6, 3%), poor (n=24; 12.1%), acceptable (n=101; 50.8%) and good (n=68; 34.2%) was 11.0 (8.0), 20.0 (4.0), 26.0 (5.0) and 38.0 (2.0), respectively. No patient has achieved an "excellent" level of knowledge. There was no significant difference in PA level (p = 0.341), BMI (p = 0.510) or age (p = 0.073) between these categories. Age was negatively correlated with knowledge about HP (p <0.05 and rho = 0.02). Conclusions: Patient's knowledge about HP did not influence the level of PA in hypertensive patients. Age, number of steps per day and BMI were not significantly different between the categories of knowledge. Public policies and organizational strategy should be addressed to improve health education and avoid sedentary behavior in this population. (Int J Cardiovasc Sci. 2020; [online].ahead print, PP.0-0)

Inspiratory Muscle Training After Heart Valve Replacement Surgery Improves Inspiratory Muscle Strength, Lung Function, and Functional Capacity: A RANDOMIZED CONTROLLED TRIAL.

PURPOSE: The aim of this study was to analyze the effects of inspiratory muscle training (IMT) as a therapeutic strategy after heart valve replacement surgery (HVRS). METHODS: A double-blind, randomized, clinical trial that included patients undergoing elective HVRS, without post-operative complications, were allocated to 2 groups: IMT group (IMT-G) and IMT placebo group (IMT-PG). The IMT started 3 d after surgery and was performed twice daily for 4 wk. Lung function, maximum inspiratory pressure (MIP) as a measure of inspiratory muscle strength, functional capacity, and quality of life were assessed pre-operatively and at the end of training. RESULTS: The IMT-G recovered pre-operative MIP and lung function values after 4 wk of training. This group also increased the distance walked during the 6-min walk test (6MWD). In the IMT-PG, the values of MIP were below those found pre-operatively, with impairment of lung function and lower 6MWD in the final evaluation. At the end of IMT, MIP was correlated with the 6MWD and with the spirometry variables. CONCLUSIONS: IMT performed for 4 wk after HVRS was effective in restoring the values of inspiratory muscle strength and lung function to the pre-operative level and increasing the functional capacity assessed by the 6MWD. Furthermore, an association between lung function and functional capacity was observed, demonstrating the clinical relevance of the use of IMT in the rehabilitation process of these patients.

Functional capacity in a rat model of heart failure: impact of myocardial infarct size.

NEW FINDINGS: What is the central question of this study? To the best of our knowledge, no studies have evaluated oxygen uptake, carbon dioxide production and exercise tolerance in rats that have undergone myocardial infarction classified by myocardial infarct (MI) size. What is the main finding and its importance? Oxygen uptake and exercise intolerance are MI size dependent, and classification based on MI size can distinguish rats with functional capacity impairment. Rats with a large MI (>40% of the left ventricle) might provide a good model for the testing of new therapies that have the potential to modify the variables of functional capacity. Oxygen uptake (V̇O2) and exercise tolerance in rats classified by myocardial infarct (MI) size are underexplored. The aim of this study was to evaluate V̇O2, carbon dioxide production (V̇CO2) and exercise tolerance in rats that had undergone myocardial infarction. Fourteen weeks after myocardial infarction or sham surgery, rats underwent an integrated approach to evaluation of left ventricular function and V̇O2/V̇O2V̇CO2V̇CO2, exercise tolerance and skeletal muscle weight. Based on determination of MI size, rats were assigned to sham-operated controls (Sham, n = 12), small myocardial infarction (SMI, n = 8) and large myocardial infarction (LMI, n = 5) groups. The LMI rats showed lower systolic (ejection fraction and fractional shortening) and diastolic (E/A ratio) left ventricular function compared with SMI. Maximal V̇O2 (∼24%, P < 0.05), V̇O2 reserve (∼30%, P < 0.05), time to exhaustion (∼36%, P < 0.05) and maximal velocity (∼30%, P < 0.05) were lower in LMI compared with sham-operated control animals, with no difference between SMI rats and sham-operated controls. Maximal V̇CO2 and respiratory exchange ratio showed no significant difference between MI rats and sham-operated control rats. The LMI rats demonstrated lower gastrocnemius weight (∼12%, P < 0.05) and soleus weight (∼19%, P = 0.07) compared with sham-operated control rats. Significant correlations between MI size, left ventricular end-diastolic pressure, right ventricle hypertrophy, pulmonary congestion, ejection fraction and fractional shortening with maximal V̇O2 and distance run were observed. Oxygen uptake and exercise intolerance are MI size dependent.

Maximal oxygen uptake and exercise tolerance are improved in rats with heart failure subjected to low-level laser therapy associated with resistance training.

Exercise tolerance and maximal oxygen uptake (VO2max) are reduced in heart failure (HF). The influence of combined resistance training (RT) and low-level laser therapy (LLLT) on exercise tolerance and VO2max in HF has not yet been explored. The aim of this study was to evaluate the influence of combined RT and LLLT on VO2max and exercise tolerance in rats with HF induced by myocardial infarction (MI). Rats were allocated to sedentary sham (Sed-Sham, n = 12), sedentary heart failure (Sed-HF, n = 9), RT heart failure (RT-HF, n = 7) and RT associated with LLLT heart failure (RT + LLLT-HF, n = 7) groups. After MI or sham surgery, rats underwent a RT and LLLT protocol (applied immediately after RT) for 8 weeks. VO2max and exercise tolerance were evaluated at the end of protocol. HF rats subjected to LLLT combined with RT showed higher VO2basal (41 %), VO2max (40 %), VO2reserve (39 %), run distance (46 %), time to exhaustion (30 %) and maximal velocity (22 %) compared with HF rats that underwent RT alone. LLLT associated with RT improved oxygen uptake and exercise tolerance compared with RT alone in HF rats.

Light-emitting diode therapy (LEDT) improves functional capacity in rats with heart failure.

The syndrome of heart failure (HF) promotes central and peripheral dysfunctions that result in functional capacity decrease, leading to fatigue, dyspnea, and exercise intolerance. The use of light-emitting diode therapy (LEDT) has shown good results reducing fatigue and exercise intolerance, when applied on skeletal muscles before or after exercises. Thereby, the aim of this study was to compare the effects of LEDT on functional capacity, aerobic power, and hemodynamic function in HF rats. Male Wistar rats (230-260 g) were randomly allocated into three experimental groups: Sham (n = 6), Control-HF (n = 4), and LEDT-HF (n = 6). The animals were subjected to an exercise performance test (ET) with gas analysis coupled in a metabolic chamber for rats performed two times (6 and 14 weeks after myocardial infarction). On the day after the baseline aerobic capacity test, the animals were submitted during 8 weeks to the phototherapy protocol, five times/week, 60 s of irradiation, 6 J delivered per muscle group. Statistical analysis was performed by one- and two-way ANOVAs with repeated measures and Student-Newman-Keuls post hoc tests (p ≤ 0.05). Comparing the percentage difference (Δ) between baseline and the final ET, there was no significant difference for the VO2max variable considering all groups. However, Sham and LEDT-HF groups showed higher relative values than the Control-HF group, respectively, for distance covered (27.7 and 32.5 %), time of exercise test (17.7 and 20.5 %), and speed (13.6 and 12.2 %). In conclusion, LEDT was able to increase the functional capacity evaluated by distance covered, time, and speed of exercise in rats with HF.

Circulatory and Ventilatory Power: Characterization in Patients with Coronary Artery Disease / Potência Circulatória e Ventilatória: Caracterização em Pacientes com Doença Arterial Coronariana

Background: Circulatory power (CP) and ventilatory power (VP) are indices that have been used for the clinical evaluation of patients with heart failure; however, no study has evaluated these indices in patients with coronary artery disease (CAD) without heart failure. Objective: To characterize both indices in patients with CAD compared with healthy controls. Methods: Eighty-seven men [CAD group = 42 subjects and healthy control group (CG) = 45 subjects] aged 40–65 years were included. Cardiopulmonary exercise testing was performed on a treadmill and the following parameters were measured: 1) peak oxygen consumption (VO2), 2) peak heart rate (HR), 3) peak blood pressure (BP), 4) peak rate-pressure product (peak systolic HR x peak BP), 5) peak oxygen pulse (peak VO2/peak HR), 6) oxygen uptake efficiency (OUES), 7) carbon dioxide production efficiency (minute ventilation/carbon dioxide production slope), 8) CP (peak VO2 x peak systolic BP) and 9) VP (peak systolic BP/carbon dioxide production efficiency). Results: The CAD group had significantly lower values for peak VO2 (p < 0.001), peak HR (p < 0.001), peak systolic BP (p < 0.001), peak rate-pressure product (p < 0.001), peak oxygen pulse (p = 0.008), OUES (p < 0.001), CP (p < 0.001), and VP (p < 0.001) and significantly higher values for peak diastolic BP (p = 0.004) and carbon dioxide production efficiency (p < 0.001) compared with CG. Stepwise regression analysis showed that CP was influenced by group (R2 = 0.44, p < 0.001) and VP was influenced by both group and number of vessels with stenosis after treatment (interaction effects: R2 = 0.46, p < 0.001). Conclusion: The indices CP and VP were lower in men with CAD than healthy controls. .

Fundamento: Os índices da Potência Circulatória (PC) e Potência Ventilatória (PV) têm sido utilizados para avaliação clínica de pacientes com insuficiência cardíaca, mas nenhum estudo avaliou esses índices em pacientes com Doença Arterial Coronariana (DAC). Objetivo: Caracterizar ambos os índices em pacientes com DAC comparados a indivíduos saudáveis. Métodos: Oitenta e sete homens [grupo DAC = 42 sujeitos e, grupo controle (GC) = 45 sujeitos] com idade entre 45 e 65 anos foram incluídos. Um Teste de Exercício Cardiopulmonar (TECP) foi realizado em esteira e as seguintes variáveis foram obtidas: 1) consumo de oxigênio (VO2) pico; 2) Frequência Cardíaca (FC) pico; 3) Pressão Arterial (PA) pico; 4) duplo produto pico (PA sistólica pico x FC pico); 5) pulso de oxigênio pico (VO2 pico dividido pela FC pico); 6) eficiência ventilatória para o consumo de oxigênio (OUES); 7) eficiência ventilatória para a produção de dióxido de carbono (VE/VCO2 slope); 8) PC (VO2 pico x PA sistólica pico); e 9) PV (PA sistólica pico dividido pelo VE/VCO2 slope). Resultados: O grupo DAC apresentou valores significativamente menores das seguintes variáveis no pico do exercício: VO2 (p < 0,001), FC (p < 0,001), PA sistólica (p < 0,001), duplo produto (p < 0,001), pulso de oxigênio (p = 0,008), OUES (p < 0,001), PC (p < 0,001) e PV (p < 0,001), e valores significativamente maiores de PA diastólica (p = 0,004) e VE/VCO2 slope (p < 0,001) em relação ao GC. Uma análise de regressão pelo método stepwise mostrou que a PC foi influenciada pelo grupo (R2 = 0,44, p < 0,001) e a PV tanto pelo grupo quanto pelo número de vasos com estenose pós tratamento (efeito de interação: R2 = 0,46, p < 0,001). Conclusion: Os índices da PC e PV foram menores em homens com DAC comparados ao GC, podendo dessa forma ser utilizados na caracterização dessa população. .

Muscular pre-conditioning using light-emitting diode therapy (LEDT) for high-intensity exercise: a randomized double-blind placebo-controlled trial with a single elite runner.

Recently, low-level laser (light) therapy (LLLT) has been used to improve muscle performance. This study aimed to evaluate the effectiveness of near-infrared light-emitting diode therapy (LEDT) and its mechanisms of action to improve muscle performance in an elite athlete. The kinetics of oxygen uptake (VO2), blood and urine markers of muscle damage (creatine kinase--CK and alanine), and fatigue (lactate) were analyzed. Additionally, some metabolic parameters were assessed in urine using proton nuclear magnetic resonance spectroscopy ((1)H NMR). A LED cluster with 50 LEDs (λ = 850 nm; 50 mW 15 s; 37.5 J) was applied on legs, arms and trunk muscles of a single runner athlete 5 min before a high-intense constant workload running exercise on treadmill. The athlete received either Placebo-1-LEDT; Placebo-2-LEDT; or Effective-LEDT in a randomized double-blind placebo-controlled trial with washout period of 7 d between each test. LEDT improved the speed of the muscular VO2 adaptation (∼-9 s), decreased O2 deficit (∼-10 L), increased the VO2 from the slow component phase (∼+348 ml min(-1)), and increased the time limit of exercise (∼+589 s). LEDT decreased blood and urine markers of muscle damage and fatigue (CK, alanine and lactate levels). The results suggest that a muscular pre-conditioning regimen using LEDT before intense exercises could modulate metabolic and renal function to achieve better performance.

The influence of low-level laser therapy on parameters of oxidative stress and DNA damage on muscle and plasma in rats with heart failure.

In heart failure (HF), there is an imbalance between the production of reactive oxygen species and the synthesis of antioxidant enzymes, causing damage to the cardiovascular function and increased susceptibility to DNA damage. The aim of this study was to evaluate the influence of low-level laser therapy (LLLT) on parameters of oxidative stress and DNA damage in skeletal muscle and plasma of rats with HF. Wistar rats were allocated into six groups: "placebo" HF rats (P-HF, n = 9), "placebo" Sham rats (P-sham, n = 8), HF rats at a dose 3 J/cm(2) of LLLT (3 J/cm(2)-HF, n = 8), sham rats at a dose 3 J/cm(2) of LLLT (3 J/cm(2)-sham, n = 8), HF rats at a dose 21 J/cm(2) of LLLT (21 J/cm(2)-HF, n = 8) and sham rats at a dose 21 J/cm(2) of LLLT (21 J/cm(2)-sham, n = 8). Animals were submitted to a LLLT protocol for 10 days at the right gastrocnemius muscle. Comparison between groups showed a significant reduction in superoxide dismutase (SOD) activity in the 3 J/cm(2)-HF group (p = 0.03) and the 21 J/cm(2)-HF group (p = 0.01) compared to the P-HF group. 2',7'-Dihydrodichlorofluorescein (DCFH) oxidation levels showed a decrease when comparing 3 J/cm(2)-sham to P-sham (p = 0.02). The DNA damage index had a significant increase either in 21 J/cm(2)-HF or 21 J/cm(2)-sham in comparison to P-HF (p = 0.004) and P-sham (p = 0.001) and to 3 J/cm(2)-HF (p = 0.007) and 3 J/cm(2)-sham (p = 0.037), respectively. Based on this, laser therapy appears to reduce SOD activity and DCFH oxidation levels, changing the oxidative balance in the skeletal muscle of HF rats. Otherwise, high doses of LLLT seem to increase DNA damage.

Respiratory muscle endurance is limited by lower ventilatory efficiency in post-myocardial infarction patients

Background: Reduced respiratory muscle endurance (RME) contributes to increased dyspnea upon exertion in patients with cardiovascular disease. Objective: The objective was to characterize ventilatory and metabolic responses during RME tests in post-myocardial infarction patients without respiratory muscle weakness. Method: Twenty-nine subjects were allocated into three groups: recent myocardial infarction group (RG, n=9), less-recent myocardial infarction group (LRG, n=10), and control group (CG, n=10). They underwent two RME tests (incremental and constant pressure) with ventilatory and metabolic analyses. One-way ANOVA and repeated measures one-way ANOVA, both with Tukey post-hoc, were used between groups and within subjects, respectively. Results: Patients from the RG and LRG presented lower metabolic equivalent and ventilatory efficiency than the CG on the second (50± 06, 50± 5 vs. 42± 4) and third part (50± 11, 51± 10 vs. 43± 3) of the constant pressure RME test and lower metabolic equivalent during the incremental pressure RME test. Additionally, at the peak of the incremental RME test, RG patients had lower oxygen uptake than the CG. Conclusions : Post-myocardial infarction patients present lower ventilatory efficiency during respiratory muscle endurance tests, which appears to explain their inferior performance in these tests even in the presence of lower pressure overload and lower metabolic equivalent. .

Reference equations for the six-minute walk distance based on a Brazilian multicenter study

BACKGROUND: It is important to include large sample sizes and different factors that influence the six-minute walking distance (6MWD) in order to propose reference equations for the six-minute walking test (6MWT). OBJECTIVE: To evaluate the influence of anthropometric, demographic, and physiologic variables on the 6MWD of healthy subjects from different regions of Brazil to establish a reference equation for the Brazilian population. METHOD: In a multicenter study, 617 healthy subjects performed two 6MWTs and had their weight, height, and body mass index (BMI) measured, as well as their physiologic responses to the test. Delta heart rate (∆HR), perceived effort, and peripheral oxygen saturation were calculated by the difference between the respective values at the end of the test minus the baseline value. RESULTS: Walking distance averaged 586±106m, 54m greater in male compared to female subjects (p<0.001). No differences were observed among the 6MWD from different regions. The quadratic regression analysis considering only anthropometric and demographic data explained 46% of the variability in the 6MWT (p<0.001) and derived the equation: 6MWDpred=890.46-(6.11×age)+(0.0345×age2)+(48.87×gender)-(4.87×BMI). A second model of stepwise multiple regression including ∆HR explained 62% of the variability (p<0.0001) and derived the equation: 6MWDpred=356.658-(2.303×age)+(36.648×gender)+(1.704×height)+(1.365×∆HR). CONCLUSION: The equations proposed in this study, especially the second one, seem adequate to accurately predict the 6MWD for Brazilians. .

Influência da idade no comportamento da frequência cardíaca na transição repouso-exercício: uma análise por deltas e regressão linear / Age influence on the heart rate behavior on the rest-exercício transition: an analysis by deltas and linear regression

INTRODUÇÃO: As modificações da frequência cardíaca (FC) durante a transição repouso-exercício podem ser caracterizadas por meio da aplicação de cálculos matemáticos simples, como: deltas 0-10 e 0-30s para inferir sobre o sistema nervoso parassimpático, e delta e regressão linear aplicados no intervalo 60-240s para inferir sobre o sistema nervoso simpático. Assim, o objetivo deste estudo foi testar a hipótese de que indivíduos jovens e de meia-idade apresentam diferentes respostas da FC em exercício de intensidade moderada e intensa, com diferentes cálculos matemáticos. MÉTODOS: Homens aparentemente saudáveis, sendo sete de meia-idade e 10 jovens, foram submetidos a testes de carga constante de intensidade moderada e intensa. Foram calculados os deltas da FC nos períodos de 0-10s, 0-30s e 60-240s e a regressão linear simples no período de 60 a 240s. Os parâmetros obtidos na análise de regressão linear simples foram: intercepto e inclinação angular. Utilizou-se o teste Shapiro-Wilk para verificar a distribuição dos dados e o teste t não pareado para comparação entre os grupos. O nível de significância estatística considerado foi 5%. RESULTADOS: O valor do intercepto e do delta 0-10s foi menor no grupo meia-idade nas duas cargas e a inclinação do ângular foi menor no grupo meia-idade no exercício moderado. CONCLUSÃO: Os indivíduos jovens apresentam retirada vagal de maior magnitude no estágio inicial da resposta da FC durante exercício dinâmico em carga constante nas intensidades analisadas e maior velocidade de ajuste da resposta simpática em exercícios moderados.

BACKGROUND: Changes in heart rate during rest-exercise transition can be characterized by the application of mathematical calculations, such as deltas 0-10 and 0-30 seconds to infer on the parasympathetic nervous system and linear regression and delta applied to data range from 60 to 240 seconds to infer on the sympathetic nervous system. The objective of this study was to test the hypothesis that young and middle-aged subjects have different heart rate responses in exercise of moderate and intense intensity, with different mathematical calculations. METHODS: Seven middle-aged men and ten young men apparently healthy were subject to constant load tests (intense and moderate) in cycle ergometer. The heart rate data were submitted to analysis of deltas (0-10, 0-30 and 60-240 seconds) and simple linear regression (60-240 seconds). The parameters obtained from simple linear regression analysis were: intercept and slope angle. We used the Shapiro-Wilk test to check the distribution of data and the "t" test for unpaired comparisons between groups. The level of statistical significance was 5%. RESULTS: The value of the intercept and delta 0-10 seconds was lower in middle age in two loads tested and the inclination angle was lower in moderate exercise in middle age. CONCLUSION: The young subjects present greater magnitude of vagal withdrawal in the initial stage of the HR response during constant load exercise and higher speed of adjustment of sympathetic response in moderate exercise.

Avaliação da frequência cardíaca à medida de pressão expiratória máxima estática e à manobra de Valsalva em jovens saudáveis / Heart rate assessment during maximal static expiratory pressure and Valsalva maneuver in healthy young men

CONTEXTUALIZAÇÃO: A medida de pressão expiratória máxima (PEmáx) possui algumas contraindicações, pois acredita-se que as respostas obtidas nessa medida são similares às respostas encontradas na manobra de Valsalva (MV). OBJETIVOS: O objetivo principal é avaliar a resposta da frequência cardíaca (FC) durante a medida da PEmáx e da MV em jovens saudáveis, em diferentes posturas, para identificar se e em qual condição a PEmáx reproduz as respostas obtidas na MV e, adicionalmente, estimar o trabalho realizado nas manobras. MÉTODO: Doze jovens saudáveis foram avaliados, orientados e familiarizados com as manobras. A MV foi composta por um esforço expiratório (40 mmHg) durante 15 segundos contra um manômetro. A PEmáx foi executada segundo a American Thoracic Society. Ambas as medidas foram realizadas nas posturas supino e sentado. Para a análise da variação da frequência cardíaca (∆FC), índice de Valsalva (IV), índice da PEmáx (IPEmáx) e o trabalho estimado das manobras (Wtotal, Wisotime, Wtotal/∆FCtotal e Wisotime/∆FCisotime ), utilizou-se ANOVA two-way com post-hoc de Holm-Sidak (p<0,05). RESULTADOS: A ∆FC durante as manobras não foi influenciada pelas posturas; entretanto, durante a MV, a ∆FC e os valores do IV foram maiores (supino: 47±9 bpm, 2,3±0,2; sentado: 41±10 bpm, 2,0±0,2, respectivamente) do que a ∆FC e os valores de IPEmáx observados durante a PEmáx (supino: 23±8 bpm, 1,5±0,2; sentado 24±8 bpm, 1,6±0,3, respectivamente) (p<0,001). Os trabalhos estimados das manobras foram estatisticamente diferentes (p<0,001) entre elas, exceto para o Wtotal/∆FC. CONCLUSÕES: Nas condições estudadas, a PEmáx não reproduz as respostas da FC observadas durante a MV em jovens saudáveis.

BACKGROUND: The measure of the maximal expiratory pressure (MEP) has some contraindications, as it is believed that the responses obtained in this measure are similar to the Valsalva maneuver (VM). OBJECTIVE: The main purpose of this study was to evaluate the heart rate responses (HR) during the MEP and the VM measures in healthy young men into different postures aiming to identify whether and in which situation the MEP reproduces the responses obtained in the VM. Additionally we aim to estimate the workload realized during the maneuvers. METHOD: Twelve healthy young men were evaluated, instructed and familiarized with the maneuvers. The VM was characterized by an expiratory effort (40 mmHg) against a manometer for 15 seconds. The MEP measure has been performed according to the American Thoracic Society. Both measures were performed at sitting and supine positions. ANOVA two-way with Holm-Sidak post-hoc test (p<0.05) was used to analyse the heart rate variation (∆HR); Valsalva index (VI); MEP index (MEPI), and the estimated workload of the maneuvers (Wtotal, Wisotime, Wtotal/∆HRtotal and Wisotime/∆HRisotime ). RESULTS: The ∆HR during the maneuvers was not influenced by the supine and sitting positions. However, the ∆HR during the VM and VI were higher (supine: 47±9 bpm, 2.3±0.2; sitting: 41±10 bpm, 2.0±0.2, respectively) than ∆HR during the MEP and MEPI values (supine: 23±8 bpm, 1.5±0.2; sitting 24±8 bpm, 1.6±0.3, respectively) (p<0.001). The estimated workload of the maneuvers was statistically different (p<0.001) between the maneuvers, except to Wtotal/∆HR. Conclusions: In the studied conditions the MEP does not reproduces the HR response observed in the VM in healthy young men.