Acute effect of photobiomodulation using light-emitting diodes (LEDs) on baroreflex sensitivity during and after constant loading exercise in patients with type 2 diabetes mellitus.

To evaluate the photobiomodulation (PBM) effect on the cardiovascular autonomic control, analyzed by baroreflex sensitivity (sequence method), during constant load exercise and recovery in diabetic men, we evaluated 11 men with type 2 diabetes (DM2) (40-64 years). The constant workload exercise protocol (TECC) was performed on two different days, 14 days apart from each other, to guarantee PBM washout period. After PBM by light-emitting diode (LED) irradiation (150 J or 300 J or placebo), 10 min of rest (REST) was performed. After this period, the volunteer was positioned on a cycloergometer to start the test (1-min rest, 3-min free-load heating, 6-min constant workload-EXERCISE, 6-min free-load cool-down, 1-min rest) followed by a sitting period of 10 min (RECOVERY). The constant workload corresponded to 80%VO2GET (gas exchange threshold) identified by a previous cardiopulmonary exercise test (CPET). PBM was applied in continuous mode, contact technique, bilaterally, on both femoral quadriceps and gastrocnemius muscle groups. The electrocardiogram R-R intervals (BioAmp FE132) and the peripheral pulse pressure signals (Finometer PRO) were collected continuously throughout the protocol. Stable sequences of 256 points were chosen at REST, EXERCISE, and RECOVERY. The baroreflex sensitivity (BRS) was computed in time domain according to the sequence method (αseq). The comparison between therapies (150 J/300 J/placebo) and condition (REST, EXERCISE, and RECOVERY) was performed using the ANOVA two-way repeated measures test. There was no interaction between therapy and conditions during the TECC. There was only the condition effect (p < 0.001), showing that the behavior of αseq was similar regardless of the therapy. Photobiomodulation with 150 J or 300 J applied previously to a moderate-intensity TECC in DM2 was not able to promote cardiovascular autonomic control changes leading to an improvement in BRS.

Critical inspiratory pressure - a new methodology for evaluating and training the inspiratory musculature for recreational cyclists: study protocol for a randomized controlled trial.

BACKGROUND: Inspiratory muscle training (IMT) has brought great benefits in terms of improving physical performance in healthy individuals. However, there is no consensus regarding the best training load, as in most cases the maximal inspiratory pressure (MIP) is used, mainly the intensity of 60% of MIP. Therefore, prescribing an IMT protocol that takes into account inspiratory muscle strength and endurance may bring additional benefits to the commonly used protocols, since respiratory muscles differ from other muscles because of their greater muscular resistance. Thus, IMT using critical inspiratory pressure (PThC) can be an alternative, as the calculation of PThC considers these characteristics. Therefore, the aim of this study is to propose a new IMT protocol to determine the best training load for recreational cyclists. METHODS: Thirty recreational cyclists (between 20 and 40 years old) will be randomized into three groups: sham (SG), PThC (CPG) and 60% of MIP, according to age and aerobic functional capacity. All participants will undergo the following evaluations: pulmonary function test (PFT), respiratory muscle strength test (RMS), cardiopulmonary exercise test (CPET), incremental inspiratory muscle endurance test (iIME) (maximal sustained respiratory pressure for 1 min (PThMAX)) and constant load test (CLT) (95%, 100% and 105% of PThMÁX) using a linear load inspiratory resistor (PowerBreathe K5). The PThC will be calculated from the inspiratory muscle endurance time (TLIM) and inspiratory loads of each CLT. The IMT will last 11 weeks (3 times/week and 55 min/session). The session will consist of 5-min warm-up (50% of the training load) and three sets of 15-min breaths (100% of the training load), with a 1-min interval between them. RMS, iIME, CLT and CPET will be performed beforehand, at week 5 and 9 (to adjust the training load) and after training. PFT will be performed before and after training. The data will be analyzed using specific statistical tests (parametric or non-parametric) according to the data distribution and their respective variances. A p value <0.05 will be considered statistically significant. DISCUSSIONS: It is expected that the results of this study will enable the training performed with PThC to be used by health professionals as a new tool to evaluate and prescribe IMT. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02984189 . Registered on 6 December 2016.

Effects of inspiratory muscle training on cardiovascular autonomic control: A systematic review.

PURPOSE: To carry out a systematic review to determine if inspiratory muscle training (IMT) promotes changes in cardiovascular autonomic responses in humans. METHODS: The methodology followed the PRISMA statement for reporting systematic review analysis. MEDLINE, PEDro, SCOPUS and PubMed electronic databases were searched from the inception to March 2017. The quality assessment was performed using a PEDro scale. The articles were included if: (1) primary objective was related to the effects of IMT on the cardiovascular autonomic nervous system, and (2) randomized clinical trials and quasi-experimental studies. Exclusion criteria were reviews, short communications, letters, case studies, guidelines, theses, dissertations, qualitative studies, scientific conference abstracts, studies on animals, non-English language articles and articles addressing other breathing techniques. Outcomes evaluated were measures of cardiovascular autonomic control, represented by heart rate variability (HRV) and blood pressure variability (BPV) indexes. RESULTS: The search identified 729 citations and a total of 6 studies were included. The results demonstrated that IMT performed at low intensities can chronically promote an increase in the parasympathetic modulation and/or reduction of sympathetic cardiac modulation in patients with diabetes, hypertension, chronic heart failure and gastroesophageal reflux, when assessed by HRV spectral analysis. However, there was no study which evaluated the effects of IMT on cardiovascular autonomic control assessed by BPV. CONCLUSIONS: IMT can promote benefits for cardiac autonomic control, however the heterogeneity of populations associated with different protocols, few studies reported in the literature and the lack of randomized controlled trials make the effects of IMT on cardiovascular autonomic control inconclusive.

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. .