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Healthy aging hemodynamics is known to exhibit a time-dependent loss of function. We aimed at verifying whether older men would have a slowed cardiac output and stroke volume dynamics in response to the onset (“on”) and on recovery (“off”) of exercise in comparison to young men. Twenty healthy active men (10 young and 10 older) were recruited. Participants performed an incremental cardiopulmonary exercise testing on a cycle ergometer, and on another day, 3 constant workload tests in different intensities. Compared to younger, older men exhibited a slower cardiac output and stroke volume dynamics in both on and off transients for all exercise intensities (all P < 0.05). During higher intensities, both younger and older men had slower hemodynamic kinetics compared to lower intensities (all P < 0.05). There was strong negative relationship between the time constant of cardiac output on-kinetics during high-intensity with maximal exercise performance in both groups (r = –0.88, P < 0.01). We interpret these findings to mean that healthy older men have slowed hemodynamic kinetics compared to younger, but this difference becomes less evident in higher intensities of exercise.

Background Coronary artery disease (CAD) lead to cardiovascular autonomic control disfunctions that can worsen exercise and/or posture adjustments. Objectives To verify the cardiovascular responses to low-intensity isometric handgrip exercise performed in different postures in CAD patients. This study tested the hypothesis that the posture influences the cardiovascular responses during isometric handgrip exercise and that the presence of CAD leads to greater cardiovascular stress during this type of exercise. Methods We investigated cardiovascular responses to isometric handgrip exercise in 15 CAD patients (CADG) and 15 health matched-control (CG). The subjects performed isometric handgrip exercise at 30% of maximum voluntary contraction until exhaustion in SUPINE, SITTING and STANDING positions. Systolic arterial pressure, diastolic arterial pressure, mean blood pressure, heart rate, peripheral vascular resistance, cardiac output, stroke volume and double product were measured during rest (baseline), exercise (peak value) and recovery in the 1st minute (REC1). Delta PB (ΔPB, peak minus baseline) and PR1 (ΔPR1, peak minus REC1) were calculated. Results Higher ΔPB and ΔPR1 of systolic and mean arterial pressure and double product were observed in STANDING when compared to SITTING and/or SUPINE. CADG showed higher ΔPB of systolic and mean arterial pressure in all postures and higher ΔPR1 of strove volume in the SITTING. Conclusion We concluded that the posture during isometric handgrip exercise influences the cardiovascular responses with STANDING leading to higher cardiovascular stress. CAD promoted higher arterial pressure responses however these responses were physiological and expected due to the presence of disease and type of exercise.

Introduction. Expiratory flow limitation (EFL) during moderate intensity exercise is present in patients with myocardial infarction (MI), whereas in healthy subjects it occurs only at a high intensity. However, it is unclear whether this limitation already manifests in those with stable coronary artery disease (CAD) (without MI). Materials and Methods. Forty-one men aged 40–65 years were allocated into (1) recent MI (RMI) group (n = 8), (2) late MI (LMI) group (n = 12), (3) stable CAD group (n = 9), and (4) healthy control group (CG) (n = 12). All participants underwent two cardiopulmonary exercise tests at a constant workload (moderate and high intensity), and EFL was evaluated at the end of each exercise workload. Results. During moderate intensity exercise, the RMI and LMI groups presented with a significantly higher number of participants with EFL compared to the CG (p<0.05), while no significant difference was observed among groups at high intensity exercise (p>0.05). Moreover, EFL was only present in MI groups during moderate intensity exercise, whereas at high intensity all groups presented EFL. Regarding the degree of EFL, the RMI and LMI groups showed significantly higher values at moderate intensity exercise in relation to the CG. At high intensity exercise, significantly higher values for the degree of EFL were observed only in the LMI group. Conclusion. The ventilatory limitation at moderate intensity exercise may be linked to the pulmonary consequences of the MI, even subjects with preserved cardiac and pulmonary function at rest, and not to CAD per se.

Our aim was to evaluate: (1) the prevalence of coexistence of heart failure (HF) and chronic obstructive pulmonary disease (COPD) in the studied patients; (2) the impact of HF + COPD on exercise performance and contrasting exercise responses in patients with only a diagnosis of HF or COPD; and (3) the relationship between clinical characteristics and measures of cardiorespiratory fitness; (4) verify the occurrence of cardiopulmonary events in the follow-up period of up to 24 months years. The current study included 124 patients (HF: 46, COPD: 53 and HF + COPD: 25) that performed advanced pulmonary function tests, echocardiography, analysis of body composition by bioimpedance and symptom-limited incremental cardiopulmonary exercise testing (CPET) on a cycle ergometer. Key CPET variables were calculated for all patients as previously described. The $${\dot{\text{V}}}$$ V ˙ E/$${\dot{\text{V}}}$$ V ˙ CO2 slope was obtained through linear regression analysis. Additionally, the linear relationship between oxygen uptake and the log transformation of $${\dot{\text{V}}}$$ V ˙ E (OUES) was calculated using the following equation: $${\dot{\text{V}}}$$ V ˙ O2 = a log $${\dot{\text{V}}}$$ V ˙ E + b, with the constant ‘a’ referring to the rate of increase of $${\dot{\text{V}}}$$ V ˙ O2. Circulatory power (CP) was obtained through the product of peak $${\dot{\text{V}}}$$ V ˙ O2 and peak systolic blood pressure and Ventilatory Power (VP) was calculated by dividing peak systolic blood pressure by the $${\dot{\text{V}}}$$ V ˙ E/$${\dot{\text{V}}}$$ V ˙ CO2 slope. After the CPET, all patients were contacted by telephone every 6 months (6, 12, 18, 24) and questioned about exacerbations, hospitalizations for cardiopulmonary causes and death. We found a 20% prevalence of HF + COPD overlap in the studied patients. The COPD and HF + COPD groups were older (HF: 60 ± 8, COPD: 65 ± 7, HF + COPD: 68 ± 7). In relation to cardiac function, as expected, patients with COPD presented preserved ejection fraction (HF: 40 ± 7, COPD: 70 ± 8, HF + COPD: 38 ± 8) while in the HF and HF + COPD demonstrated similar levels of systolic dysfunction. The COPD and HF + COPD patients showed evidence of an obstructive ventilatory disorder confirmed by the value of %FEV1 (HF: 84 ± 20, COPD: 54 ± 21, HF + COPD: 65 ± 25). Patients with HF + COPD demonstrated a lower work rate (WR), peak oxygen uptake ($${\dot{\text{V}}}$$ V ˙ O2), rate pressure product (RPP), CP and VP compared to those only diagnosed with HF and COPD. In addition, significant correlations were observed between lean mass and peak $${\dot{\text{V}}}$$ V ˙ O2 (r: 0.56 p 2 pulse (r: 0.58 p LCO) and WR (r: 0.51 p LCO and VP (r: 0.40 p: 0.002), forced expiratory volume in first second (FEV1) and peak $${\dot{\text{V}}}$$ V ˙ O2 (r: 0.52; p 1 and WR (r: 0.62; p 1 and DLCO influence important responses to exercise.

OBJECTIVES: To identify the clinical discriminative value and determinants of arterial stiffness in individuals with type 2 diabetes mellitus (T2DM). METHODS: This prospective cohort study included 51 individuals (53.57±9.35 years) diagnosed with T2DM (stage glucose≥126 mg/dL; diagnostic time: 87.4±69.8 months). All participants underwent an initial evaluation of personal habits, medications, and history; arterial stiffness assessment by carotid-femoral pulse wave velocity (cfPWV) using SphygmoCor; and blood laboratory analysis. A statistical analysis was performed using SPSS software, and values of p≤0.05 were considered significant. RESULTS: A cut-off cfPWV value of 7.9 m/s was identified for T2DM [Sensitivity (SE): 90% and Specificity (SP): 80%]. A subgroup analysis revealed higher glycated hemoglobin (Hb1Ac) (p=0.006), obesity (p=0.036), and dyslipidemia (p=0.013) than those with cfPWV ≥7.9 m/s. Multivariate analysis identified higher stage glucose (p=0.04), Hb1Ac (p=0.04), hypertension (p=0.001), and dyslipidemia (p=0.01) as determinant factors of cfPWV; positive and significant correlation between cfPWV and glucose (r=0.62; p=0.0003) and Hb1Ac (r=0.55; p=0.0031). CONCLUSIONS: In T2DM, an indicator of the discriminative value of arterial stiffness was cfPWV of 7.9 m/s. Clinical findings and comorbidities, such as hypertension, glucose, poor glycemic control, and dyslipidemia, were associated with and were determinants of arterial stiffness in T2DM. Reinforcement of monitoring risk factors, such as hypertension, dyslipidemia, and glycemic control, seems to be essential to the process of arterial stiffening. Confirmation of this discriminative value in larger populations is recommended.

Polliana B Dos Santos,1 Rodrigo P Simões,1,2 Cássia da L Goulart,1 Meliza G Roscani,3 Renan S Marinho,1 Patrícia Faria Camargo,1 Renata F Arbex,1 Guilherme Casale,3 Cláudio R Oliveira,3 Renata G Mendes,1 Ross Arena,4 Audrey Borghi-Silva1 1Cardiopulmonary Physical Therapy Laboratory, Federal University of Sao Carlos, Sao Carlos, Brazil; 2Postgraduate Program in Rehabilitation Sciences, Federal University of Alfenas, Minas Gerais, Brazil; 3Department of Medicine, Federal University of Sao Carlos, Sao Carlos, Brazil; 4Department of Physical Therapy, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL, USACorrespondence: Audrey Borghi-SilvaCardiopulmonary Physiotherapy Laboratory, Federal University of São Carlos, UFSCar, São Carlos, São Paulo, BrazilTel +551633066704Fax +551633612081Email audrey@ufscar.brAim: Our aim was to assess: 1) the impact of the eccentric left ventricular hypertrophy (ELVH) on exercise performance in patients diagnosed with chronic heart failure (CHF) alone and in patients with co-existing CHF and chronic obstructive pulmonary disease (COPD) and 2) the relationship between left and right cardiac function measurements obtained by doppler echocardiography, clinical characteristics and primary measures of cardiorespiratory fitness.Methods: The current study included 46 patients (CHF:23 and CHF+COPD:23) that performed advanced pulmonary function tests, echocardiography and symptom-limited, incremental cardiopulmonary exercise testing (CPET) on a cycle ergometer.Results: Patients with CHF+COPD demonstrated a lower work rate, peak oxygen uptake (VO2), oxygen pulse, rate pressure product (RPP), circulatory power (CP) and ventilatory power (VP) compared to those only diagnosed with CHF. In addition, significant correlations were observed between VP and relative wall thickness (r: 0.45 p: 0.03),VE/VCO2 intercept and Mitral E/e’ ratio (r: 0.70 p: 0.003) in the CHF group. Significant correlations were found between indexed left ventricle mass and RPP (r: − 0.47; p: 0.02) and relative VO2 and right ventricle diameter (r: − 0.62; p: 0.001) in the CHF+COPD group.Conclusion: Compared to a diagnosis of CHF alone, a combined diagnosis of CHF+COPD induced further impairments in cardiorespiratory fitness. Moreover, echocardiographic measures of cardiac function are related to cardiopulmonary exercise performance and therefore appear to be an important therapeutic target when attempting to improve exercise performance and functional capacity.Keywords: heart failure, chronic obstructive pulmonary disease, eccentric hypertrophy, ventricular dysfunction, cardiopulmonary exercise testing, echocardiography

Impairment of cardiac autonomic integrity is common in chronic obstructive pulmonary disease (COPD) patients. The influence of the interaction between clinical and severity status on brain-heart autonomic axis (BHAA) is not well known. We aimed to investigate the BHAA function across different clinical status and severity of COPD.Cross-sectional study involving 77 COPD patients allocated into four groups according to clinical status [acute exacerbation (GAE) or stable (GST)] and severity [less (-) or more (+)]: 1) GAE-, n = 13; 2) GAE+, n = 20; 3) GST-, n = 23; and 4) GST+, n = 21. Heart rate variability (HRV) at rest and heart rate recovery (HRR) after 6-min walk test were markers of BHAA. Mean R-R, STDRR, RMSSD, RRtri, HF, LF, SD1, SD2, ApEn and SampEn were the HRV indexes and, HRR was obtained as: HR at 1st min of recovery minus peak HR.A main effect of clinical status (p 0.001) was found to vagal modulation in GAE-vs. GST- (RMSSD: 25.0 ± 14.8 vs. 12.6 ± 5.5 ms; SD1: 18.0 ± 10.6 vs. 8.9 ± 3.9 ms) and to GAE + vs. GST+ (RMSSD: 26.4 ± 15.2 vs. 15.4 ± 6.3 ms; SD1: 18.3 ± 11.2 vs. 10.9 ± 4.5 ms). An effect of clinical status (p = 0.032) and severity (p = 0.030) were found to HF (vagal) in GAE + compared to GAE- and GST+ (264.7 ± 239.0 vs. 134.7 ± 169.7 and 135.8 ± 139.7 msIn COPD patients, clinical status (AECOPD or stable) was more dominant than the severity on BHAA function. A more pronounced parasympathetic modulation was found in AECOPD patients with a lower HRR to exercise.

Background Circulatory (CP) and ventilatory power (VP) have been used to improve the prognostic accuracy of cardiopulmonary exercise tests in cardiovascular disease, such as coronary artery disease. However, the effects of combined resistance and aerobic exercise program on VP and CP, especially in type 2 diabetes patients, have not been adequately investigated. Thus, this new parameter can be useful to prescribe exercise programs more assertive for this population. The present study aimed to assess the effect of 3 months of combined resistance and aerobic exercise training (CET) on CP and VP in patients with type 2 diabetes. Methods A randomized controlled trial was conducted involving 48 diabetic patients with an average age of 52.4 (±8.01) years old. The subjects were randomized into two groups: sedentary (SG, n = 15) and the CET group (n = 19). Cardiopulmonary exercise testing (symptom-limited incremental) was performed on a cycle ergometer, and the following parameters were measured: relative VO2 , VE /VCO2 slope, linear relationship between oxygen uptake and minute ventilation, and VCO2 . CET was performed with 30-min aerobic and 30-min resistance exercises three times a week for 12 weeks. Results Significant (p .05 and d ≥ 0.80) that favoured CET. Conclusion Three months of combined exercise training improved VP and CP indices in patients with type 2 diabetes when compared with a sedentary group.

Both deterioration of the mechanical vascular properties of barosensitive vessels and autonomic derangement lead to modification of baroreflex sensitivity (BRS) in coronary artery disease (CAD) individuals. Type 2 diabetes (T2D) reduces BRS as well even in absence of cardiac autonomic neuropathy. The aim of the study is to clarify whether, assigned the degree of mechanical vascular impairment and without cardiac autonomic neuropathy, the additional autonomic dysfunction imposed in CAD patients by T2D (CAD-T2D) decreases BRS further. We considered CAD (n = 18) and CAD-T2D (n = 19) males featuring similar increases of average carotid intima media thickness (ACIMT) and we compared them to age- and gender-matched healthy (H, n = 19) subjects. BRS was computed from spontaneous beat-to-beat variability of heart period (HP) and systolic arterial pressure (SAP) at supine resting (REST) and during active standing (STAND). BRS was estimated via methods including time domain, spectral, cross-spectral, and model-based techniques. We found that (i) at REST BRS was lower in CAD and CAD-T2D groups than in H subjects but no difference was detected between CAD and CAD-T2D individuals; (ii) STAND induced an additional decrease of BRS visible in all the groups but again BRS estimates of CAD and CAD-T2D patients were alike; (iii) even though with different statistical power, BRS markers reached similar conclusions with the notable exception of the BRS computed via model-based approach that did not detect the BRS decrease during STAND. In presence of a mechanical vascular impairment, indexes estimating BRS from spontaneous HP and SAP fluctuations might be useless to detect the additional derangement of the autonomic control in CAD-T2D without cardiac autonomic neuropathy compared to CAD, thus limiting the applications of cardiovascular variability analysis to typify CAD-T2D individuals. Graphical abstract Graphical representation of the baroreflex sensitivity (BRS) estimated from spontaneous fluctuations of heart period and systolic arterial pressure via transfer function (TF) in low frequency (LF) band (from 0.04 to 0.15 Hz). BRS was reported as a function of the group (i.e., healthy (H), coronary artery disease (CAD) and CAD with type 2 diabetes (CAD-T2D) groups) at REST (black bars) and during STAND (white bars). Values are shown as mean plus standard deviation. The symbol "*" indicates a significant difference between conditions within the same group (i.e., H, CAD, or CAD-T2D) and the symbol "§" indicates a significant difference between groups within the same experimental condition (i.e., REST or STAND). BRS cannot distinguish CAD and CAD-T2D groups both at REST and during STAND, while it is useful to distinguish experimental conditions and separate pathological groups from H subjects.

Fundamento: O treinamento intervalado de alta intensidade (TIAI) tem sido utilizado como estrategia de exercicio cardiovascular para promover maior adesao na reabilitacao cardiovascular. No entanto, pouco se sabe sobre o efeito dessa modalidade de treinamento no controle autonomico cardiaco. Objetivo: Realizar uma revisao sistematica para avaliar os efeitos do TIAI nas respostas autonomicas cardiacas em humanos. Metodos: PEDro, SCOPUS e PubMed foram pesquisados desde o inicio ate 29 de marco de 2018. Alem disso, a qualidade metodologica e os relatorios estatisticos de todos os ensaios clinicos elegiveis foram avaliados pela escala PEDro. Os artigos eram elegiveis se: O objetivo principal estivesse relacionado aos efeitos do TIAI no sistema nervoso autonomo cardiaco. Os desfechos avaliados foram medidas indiretas de controle autonomico cardiaco, representadas por indices de VFC. Resultados: As estrategias de busca resultaram em 339 citacoes e 2 citacoes adicionais foram identificadas por meio de outras fontes. Apos excluir os artigos duplicados e revisar o texto completo, 6 artigos foram incluidos. De maneira geral, os resultados mostraram uma melhora na modulacao parassimpatica e / ou simpatica apos TIAI, quando avaliada por indices lineares e nao lineares de VFC. Conclusoes: O TIAI e uma ferramenta promissora para melhorar o controle autonomico cardiaco, com mais recomendacao em individuos saudaveis e pacientes com sindrome metabolica.

Despite the appeal of ultra-short-term heart rate variability (HRV) methods of analysis applied in the clinical and research settings, the number of studies that have investigated HRV by analyzing R-R interval (RRi) recordings shorter than 5 min is still limited. Moreover, ultra-short-term HRV analysis has not been extensively validated during exercise and, currently, no indications exist for its applicability during resistance exercise. The aim of the present study was to compare ultra-short-term HRV analysis with standard short-term HRV analysis during low-intensity, dynamic, lower limb resistance exercise in healthy elderly subjects. Heart rate (HR) and RRi signals were collected from 9 healthy elderly men during discontinuous incremental resistance exercise consisting of 4-min intervals at low intensities (10, 20, 30, and 35% of 1-repetition maximum). The original RRi signals were segmented into 1-, 2-, and 3-min sections. HRV was analyzed in the time domain (root mean square of the of differences between adjacent RRi, divided by the number of RRi, minus one [RMSSD]), RRi mean value and standard deviation [SDNN] (percentage of differences between adjacent NN intervals that are greater than 50 ms [pNN50]), and by non-linear analysis (short-term RRi standard deviation [SD1] and long-term RRi standard deviation [SD2]). No significant difference was found at any exercise intensity between the results of ultra-short-term HRV analysis and the results of standard short-term HRV analysis. Furthermore, we observed excellent (0.70 to 0.89) to near-perfect (0.90 to 1.00) concordance between linear and non-linear parameters calculated over 1- and 2-min signal sections and parameters calculated over 3-min signal sections. Ultra-short-term HRV analysis appears to be a reliable surrogate of standard short-term HRV analysis during resistance exercise in healthy elderly subjects.

Objective: To investigate the cardiac autonomic responses during upper versus lower limb discontinuous resistance exercise (RE) at different loads in healthy older men. Method: Ten volunteers (65±1.2 years) underwent the one-repetition maximum (1RM) test to determine the maximum load for the bench press and the leg press. Discontinuous RE was initiated at a load of 10%1RM with subsequent increases of 10% until 30%1RM, followed by increases of 5%1RM until exhaustion. Heart rate (HR) and R-R interval were recorded at rest and for 4 minutes at each load applied. Heart rate variability (HRV) was analyzed in 5-min segments at rest and at each load in the most stable 2-min signal. Results: Parasympathetic indices decreased significantly in both exercises from 30%1RM compared to rest (rMSSD: 20±2 to 11±3 and 29±5 to 12±2 ms; SD1: 15±2 to 8±1 and 23±4 to 7±1 ms, for upper and lower limb exercise respectively) and HR increased (69±4 to 90±4 bpm for upper and 66±2 to 89±1 bpm for lower). RMSM increased for upper limb exercise, but decreased for lower limb exercise (28±3 to 45±9 and 34±5 to 14±3 ms, respectively). In the frequency domain, the sympathetic (LF) and sympathovagal balance (LF/HF) indices were higher and the parasympathetic index (HF) was lower for upper limb exercise than for lower limb exercise from 35% of 1RM. Conclusions: Cardiac autonomic change occurred from 30% of 1RM regardless of RE limb. However, there was more pronounced sympathetic increase and vagal decrease for upper limb exercise than for lower limb exercise. These results provide a basis for more effective prescription of RE to promote health in this population.

Summary Background Conventional coronary artery bypass grafting (C-CABG) and off-pump CABG (OPCAB) surgery may produce different patients’ outcomes, including the extent of cardiac autonomic (CA) imbalance. The beneficial effects of an exercise-based inpatient programme on heart rate variability (HRV) for C-CABG patients have already been demonstrated by our group. However, there are no studies about the impact of a cardiac rehabilitation (CR) on HRV behaviour after OPCAB. The aim of this study is to compare the influence of both operative techniques on HRV pattern following CR in the postoperative (PO) period. Methods Cardiac autonomic function was evaluated by HRV indices pre- and post-CR in patients undergoing C-CABG (n = 15) and OPCAB (n = 13). All patients participated in a short-term (approximately 5 days) supervised CR programme of early mobilization, consisting of progressive exercises, from active-assistive movements at PO day 1 to climbing flights of stairs at PO day 5. Results Both groups demonstrated a reduction in HRV following surgery. The CR programme promoted improvements in HRV indices at discharge for both groups. The OPCAB group presented with higher HRV values at discharge, compared to the C-CABG group, indicating a better recovery of CA function. Conclusion Our data suggest that patients submitted to OPCAB and an inpatient CR programme present with greater improvement in CA function compared to C-CABG.

The purposes of this study were to determine anaerobic threshold (AT) during discontinuous dynamic and resistive exercise protocols by analysing of heart rate variability (HRV) and blood lactate (BL) in healthy elderly subjects and compare the cardiovascular, metabolic and autonomic variables obtained from these two forms of exercise. Fourteen elderly (70 ± 4 years) apparently healthy males underwent the following tests: (i) incremental ramp test on cycle ergometer, (ii) one repetition maximum (1RM) leg press at 45°, (iii) a discontinuous exercise test on a cycle ergometer (DET-C) protocol and (iv) a resistance exercise leg press (DET-L) protocol. Heart rate, blood pressure and BL were obtained during each increment of exercise intensity. No significant differences (P>0·05) were found between methods of AT determination (BL and HRV) nor the relative intensity corresponding to AT (30% of maximum intensity) between the types of exercise (DET-C and DET-L). Furthermore, no significant differences (P>0·05) were found between the DET-C and DET-L in relation to HRV, however, the DET-L provided higher values of systolic blood pressure and BL (P

This purpose of this study was to: 1) determine the intensity corresponding to anaerobic threshold (AT) during a discontinuous resistance exercise protocol in healthy young and elderly subjects by analyzing heart rate variability (HRV) and blood lactate (BL) and 2) investigate the effect of aging on these variables. A total of 28 individuals, 14 young and 14 elderly healthy men underwent one-repetition maximum (1RM) testing to determine maximum load on the leg press. Discontinuous resistance exercise testing was initiated at 10% of the 1RM with subsequent increases of 10%. The load corresponding to AT was approximately 30% 1RM in both groups. The determination of AT by HRV was associated with BL responses (p

Introduction Indexes derived from spontaneous heart period (HP) and systolic arterial pressure (SAP) fluctuations can detect autonomic dysfunction in individuals with type 2 diabetes mellitus (DM) associated to cardiovascular autonomic neuropathy (CAN) or other neuropathies. It is unknown whether HP and SAP variability indexes are sensitive enough to detect the autonomic dysfunction in DM patients without CAN and other neuropathies. Methods We evaluated 68 males aged between 40 and 65 years. The group was composed by DM type 2 DM with no manifest neuropathy (n = 34) and healthy (H) subjects (n = 34). The protocol consisted of 15 minutes of recording of HP and SAP variabilities at rest in supine position (REST) and after active standing (STAND). The HP power in the high frequency band (HF, from 0.15 to 0.5 Hz), the SAP power in the low frequency band (LF, from 0.04 to 0.15 Hz) and BRS estimated via spectral approach and sequence method were computed. Results The HF power of HP was lower in DM patients than in H subjects, while the two groups exhibited comparable HF power of HP during STAND. The LF power of SAP was similar in DM and H groups at REST and increased during STAND in both groups. BRSs estimated in the HF band and via baroreflex sequence method were lower in DM than in H and they decreased further during STAND in both populations. Conclusion Results suggest that vagal control of heart rate and cardiac baroreflex control was impaired in type 2 DM, while sympathetic control directed to vessels, sympathetic and baroreflex response to STAND were preserved. Cardiovascular variability indexes are sensitive enough to typify the early, peculiar signs of autonomic dysfunction in type-2 DM patients well before CAN becomes manifest.

The aim of this study was to assess the effects of resistance training on ladders (RTL) on MMP(-2) expression and blood lactate concentration [La-]. 30 male (3 months of age), albino rats were divided into 3 groups: sedentary control (SC, n=10), low resistance exercise training (Low-IntRT, n=10) and high-intensive exercise training (High-IntRT, n=10). Animals of High-IntRT were submitted to a progressively increasing overload in relation to body weight until exhaustion, while the Low-IntRT group performed the same exercise regimen with no external load. The program had a frequency of 3 times per week over 8 weeks. MMP(-2) expression of tibialis anterior muscle and [La-] were measured. While there was a significant increase of MMP(-2) (pro-form) in both groups, only High-IntRT significantly increased MMP(-2) in active-form (p

Obesity is a major public health concern on a global scale. Bariatric surgery is among the treatment options, resulting in significant and sustainable weight loss as well as amelioration of comorbidities. The purpose of this study was to evaluate whether a 12-week aerobic exercise program positively impacts heart rate variability (HRV) and functional capacity after gastric bypass surgery (GBS) in a female cohort. Of the 52 patients initially recruited, 21 were randomized to a training group (TG) or control group and successfully completed the study. Patients were tested on two occasions: 1 week before GBS and 4 months after GBS. Anthropometric variables, body composition, record of heart rate and R-R intervals, and 6-min walk test (6MWT) were assessed at both time points. The TG underwent an aerobic exercise training program on a treadmill (1-h session, totaling 36 sessions over 12 weeks). The main findings from this study were: (1) only the TG demonstrated a significant increase (p

BACKGROUND: A synchronism exists between the respiratory and cardiac cycles. However, the influence of the inspiratory muscle weakness in chronic obstructive pulmonary disease (COPD) on cardiac autonomic control is unknown. The purpose of the present investigation was to evaluate the influence of respiratory muscle strength on autonomic control in these patients. METHODS: Ten chronic obstructive pulmonary disease patients (69±9 years; FEV1/FVC 59±12% and FEV1 41±11% predicted) and nine age-matched healthy volunteers (64±5 years) participated in this study. Heart-rate variability (HRV) was obtained at rest and during respiratory sinusal arrhythmia maneuver (RSA-M) by electrocardiograph. RESULTS: Chronic obstructive pulmonary disease patients demonstrated impaired cardiac autonomic modulation at rest and during RSA-M when compared with healthy subjects (p

Objective: To evaluate heart rate variability during an inspiratory muscle endurance protocol at three different load levels [30%, 60% and 80% of maximal inspiratory pressure], in patients who had previously undergone coronary artery bypass grafting. Methods: Nineteen late postoperative myocardial revascularization patients participating in a cardiovascular rehabilitation program were studied. Maximal inspiratory pressure maneuvers were performed. An inspiratory muscle endurance protocol at 30%, 60% and 80% of maximal inspiratory pressure was applied for four minutes each, in random order. Heart rate and RR intervals were recorded and heart rate variability was analyzed by time (RMSSD-the mean of the standard deviations for all R-R intervals, and RMSM-root-mean square differences of successive R-R intervals) and frequency domains indices (high and low frequency) in normalized units. ANOVA for repeated measurements was used to compare heart rate variability indices and Student t-test was used to compare the maximal inspiratory pressure and maximal expiratory pressure values. Results: Heart rate increased during performance of maximal respiratory pressures maneuvers, and the maximal inspiratory pressure and maximal expiratory pressure mean values were significantly lower than predicted values (P

The aim of this study was to determine the anaerobic threshold (AT) in a population of healthy and post-myocardial infarction men by applying Hinkley's mathematical method and comparing its performance to the ventilatory visual method. This mathematical model, in lieu of observer-dependent visual determination, can produce more reliable results due to the uniformity of the procedure. 17 middle-aged men (55±3 years) were studied in 2 groups: 9 healthy men (54±2 years); and 8 men with previous myocardial infarction (57±3 years). All subjects underwent an incremental ramp exercise test until physical exhaustion. Breath-by-breath ventilatory variables, heart rate (HR), and vastus lateralis surface electromyography (sEMG) signal were collected throughout the test. Carbon dioxide output (V˙CO2), HR, and sEMG were studied, and the AT determination methods were compared using correlation coefficients and Bland-Altman plots. Parametric statistical tests were applied with significance level set at 5%. No significant differences were found in the HR, sEMG, and ventilatory variables at AT between the different methods, such as the intensity of effort relative to AT. Moreover, important concordance and significant correlations were observed between the methods. We concluded that the mathematical model was suitable for detecting the AT in both healthy and myocardial infarction subjects.

Background Recent studies have shown that the magnitude of the metabolic and autonomic responses during progressive resistance exercise (PRE) is associated with the determination of the anaerobic threshold (AT). AT is an important parameter to determine intensity in dynamic exercise. Objectives To investigate the metabolic and cardiac autonomic responses during dynamic resistance exercise in patients with Coronary Artery Disease (CAD). Method Twenty men (age = 63±7 years) with CAD [Left Ventricular Ejection Fraction (LVEF) = 60±10%] underwent a PRE protocol on a leg press until maximal exertion. The protocol began at 10% of One Repetition Maximum Test (1-RM), with subsequent increases of 10% until maximal exhaustion. Heart Rate Variability (HRV) indices from Poincaré plots (SD1, SD2, SD1/SD2) and time domain (rMSSD and RMSM), and blood lactate were determined at rest and during PRE. Results Significant alterations in HRV and blood lactate were observed starting at 30% of 1-RM (p

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/VCO2slope).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.

The aim of this study was to evaluate the relationship between Shannon entropy (SE) and symbolic analysis (SA) of heart rate variability at rest in 3 groups: patients with coronary artery disease (CAD), CAD with diabetes mellitus (CAD-DM), and healthy individuals (H). We evaluated 44 men into the groups (CAD, n=16, CAD-DM, n=13 and H, n=15). The R-R intervals (R-Ri) were recorded at rest in the supine position for 15 minutes. SA analysis classified patterns of R-Ri according to the number of variations into stable and unstable patterns. Significant and negative correlation was found between SE and the percentage of stable patterns for CAD and CAD-DM. Positive correlation was found between SE and the percentage of unstable patterns in all the groups. We conclude that complexity of cardiovascular control had a positive relationship with the cardiac parasympathetic modulation in all groups and negative relationship with the sympathetic modulation in CAD and CAD-DM groups.

To assess whether the same exercise-based inpatient program applied to patients with normal and reduced left ventricular function (LVF) evokes a similar cardiac autonomic response after coronary artery bypass graft (CABG).Forty-four patients post-CABG, subgrouped according to normal LVF [LVFN: n = 23; left ventricular ejection fraction (LVEF) ≥ 55%] and reduced LVF (LVFR: n = 21; LVEF 35-54%), were included. All initiated the exercise protocol on post-operative day 1 (PO1), following a whole progressive program until discharge. Cardiac autonomic response was assessed by the indices of heart rate variability (HRV) at rest and during exercise (extremity range of motion and ambulation).During ambulation, lower values of HRV indices were found in the LVFR group compared with the LVFN group [standard deviation of all RR (STDRR; 6.1 ± 2.7 versus 8.9 ± 4.7 ms), baseline width of the RR histogram (TINN; 30.6 ± 14.8 versus 45.8 ± 24.9 ms), SD2 (14.8 ± 8.0 versus 21.3 ± 9.0 ms), Shannon entropy (3.6 ± 0.5 versus 3.9 ± 0.4) and correlation dimension (0.08 ± 0.2 versus 0.2 ± 0.2)]. Also, when comparing the ambulation to rest change, lower values were observed in the LVFR group for linear (STDRR, TINN, RR TRI, rMSSD) and non-linear (SD2 and correlation dimension) HRV indices (p0.05). On PO1, we observed only intra-group differences between rest and exercise (extremity range of motion), for mean intervals between heart beats and heart rate.For patients with LVFN, the same inpatient exercise protocol triggered a more attenuated autonomic response compared with patients with LVFR. These findings have implications as to how exercise should be prescribed according to LVF in the early stages following recovery from CABG. Implications for Rehabilitation Exercise-based inpatient program, performed by post-CABG patients who have normal left ventricular function, triggered a more attenuated cardiac autonomic response compared with patients with reduced left ventricular function. Volume of the inpatient exercises should be prescribed according to the left ventricular function in the early stages following recovery from CABG.

Made available in DSpace on 2022-04-28T18:57:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-01 The aim of this study was to assess the effects of metabolic and autonomic nervous control on high-intensity resistance training (HRT) as determined by pancreatic glucose sensitivity (GS), insulin sensitivity (IS), blood lactate ([La]), and heart rate variability (HRV) in rats. Thirty male, albino Wistar rats (292 6 20 g) were divided into 3 groups: sedentary control (SC), low-resistance training (LRT), and HRT. The animals in the HRT group were submitted to a high-resistance protocol with a progressively increasing load relative to body weight until exhaustion, whereas the LRT group performed the same exercise regimen with no load progression. The program was conducted 3 times per week for 8 weeks. The [La], parameters related to the functionality of pancreatic tissue, and HRV were measured. There was a significant increase in peak [La] only in the HRT group, but there was a reduction in [La] when corrected to the maximal load in both trained groups (LRT and HRT, p < 0.05). Both trained groups exhibited an increase in IS; however, compared with SC and LRT, HRT demonstrated a significantly higher GS posttraining (p < 0.05). With respect to HRV, the low-frequency (LF) band, in milliseconds squared, reduced in both trained groups, but the high-frequency band, in milliseconds squared and nu, increased, and the LF in nu, decreased only in the HRT group (p < 0.05). The HRT protocol produced significant and beneficial metabolic and cardiac autonomic adaptations. These results provide evidence for the positive benefits of HRT in counteracting metabolic and cardiovascular dysfunction. © 2012 National Strength and Conditioning Association. Cardiopulmonary Physiotherapy Laboratory Physiotherapy Department Federal University of Sao Carlos, São Carlos Medicine Department Federal University of Sao Carlos, São Carlos Physiological Sciences Department Federal University of Sao Carlos, São Carlos Healthy Sciences Department Methodist University of Piracicaba, Piracicaba Physiotherapy Department Medicine Faculty of Ribeirão Preto Estadual University of São Paulo, Ribeirão Preto Department of Physical Therapy Virginia Commonwealth University, Richmond, VA Department of Internal Medicine Virginia Commonwealth University, Richmond, VA

Objective: Cardiac rehabilitation is associated with cardiac autonomic and physiological benefits. However, it is unclear whether baseline left ventricular function (LVF) impacts on training-induced cardiac autonomic adaptations. The aim of this study was to assess the cardiac autonomic adaptations in patients with varying left ventricular function profiles undergoing coronary artery bypass grafting and cardiac rehabilitation. Design: Assessor-blinded prospective trial. Patients: Forty-four patients undergoing coronary artery bypass grafting, divided into normal LVFN (≥ 55%, n = 23) or reduced LVFR (35–54%, n = 21) were evaluated. Method: Cardiac autonomic function was evaluated by heart rate variability indexes obtained both pre- and post-cardiac rehabilitation. All patients participated in a short-term (approximately 5 days) supervised inpatient physiotherapy program. Results: There were differences in heart rate variability indexes, correlation dimension and SD2 according to time and group (e.g. interaction time (effect of cardiac rehabilitation) vs group (LVFN vs LVFR), p = 0.04). Simple main effects analysis showed that the LVFR group benefited to a greater degree from cardiac rehabilitation compared with the LVFN group. Heart rate variability indexes increased significantly in the former group compared with the latter. Conclusion: Among post-coronary artery bypass grafting patients engaged in short-term inpatient rehabilitation, those with reduced left ventricular function are most likely to have better cardiac autonomic adaptations to exercisebased rehabilitation.

The purpose of this study was to investigate the behavior of heart rate (HR) and HR variability (HRV) during different loads of resistance exercise (incline bench press) in patients with coronary artery disease (CAD) and healthy sedentary controls. Ten healthy men (65 ± 1.2 years, control group, CG) and 10 men with clinically stable CAD (66 ± 2.4 years, CADG) were recruited. A discontinuous progressive protocol was applied with an initial load of 10% of the maximum load achieved in the 1RM (1 repetition maximum) with increases of 10% until 30% 1RM was reached, which was followed by subsequent increases of 5% 1RM until exhaustion. HRV was analyzed by linear and non-linear methods. There was a significant reduction in rMSSD (CG: 20 ± 2 to 11 ± 3 ms; CADG: 19 ± 3 to 9 ± 1 ms) and SD1 indexes (CG: 14 ± 2 to 8 ± 1 ms; CADG: 14 ± 2 to 7 ± 1 ms). An increase in HR (CG: 69 ± 5 to 90 ± 5 bpm; CADG: 62 ± 4 to 75 ± 4 bpm) and in systolic blood pressure (CG: 124 ± 3 to 138 ± 3 mmHg; CADG: 122 ± 6 to 126 ± 9 bpm) were observed (P < 0.05) when comparing pre-effort rest and 40% 1RM in both groups. Furthermore, an increase in RMSM index was also observed (CG: 28 ± 3 to 45 ± 9 ms; CADG: 22 ± 2 to 79 ± 33 ms), with higher values in CADG. We conclude that loads up to 30% 1RM during incline bench press result in depressed vagal modulation in both groups, although only stable CAD patients presented sympathetic overactivity at 20% 1RM upper limb exercise.

Coronary artery bypass grafting (CABG) is accompanied by severe impairment of cardiac autonomous regulation (CAR). This study aimed to determine whether a short-term physiotherapy exercise protocol post-CABG, during inpatient cardiac rehabilitation (CR), might improve CAR.Seventy-four patients eligible for CABG were recruited and randomised into physiotherapy exercise group (EG) or physiotherapy usual care group (UCG). EG patients underwent a short-term supervised inpatient physiotherapy exercise protocol consisting of an early mobilisation with progressive exercises plus usual care (respiratory exercises). UCG only received respiratory exercises. Forty-seven patients (24 EG and 23 UGC) completed the study. Outcome measures of CAR included linear and non-linear measures of heart rate variability (HRV) assessed before discharge.By hospital discharge, EG presented significantly higher parasympathetic HRV values [rMSSD, high frequency (HF), SD1)], global power (STD RR, SD2), non-linear HRV indexes [detrended fluctuation analysis (DFA)alpha1, DFAalpha2, approximate entropy (ApEn)] and mean RR compared to UCG (p0.05). Conversely, higher values of mean HR, low frequency (LF) (sympathetic activity) and the LF/HF (global sympatho-vagal balance) were found in the UCG.A short-term supervised physiotherapy exercise protocol during inpatient CR improves CAR at the time of discharge. Thus, exercise-based inpatient CR might be an effective non-pharmacological tool to improve autonomic cardiac tone in patient's post-CABG.

Baroreflex dysfunction has been demonstrated in fibromyalgia syndrome (FMS). However, there are few studies evaluating the effectiveness of hydrotherapy programs on cardiovascular autonomic control in this population. This study evaluates the effects of a 16-week hydrotherapy program on baroreflex sensitivity (BRS) in women with FMS. Eight women with FMS took part in the study. The electrocardiogram, non-invasive finger blood pressure and respiratory activity were continuously recorded for all participants during 15 min in supine and 15 min in orthostatic (active standing) positions, before and after a 16week hydrotherapy program (Post16). The BRS was estimated via cross-spectral analysis, computed as the square root of the ratio of the low frequency (LF) band power of heart period on the LF power of systolic arterial pressure (αLF). The hydrotherapy program comprised 32 sessions of 45 min of pool exercises twice a week, for 16 weeks. At baseline there was no significant difference for the αLF index between supine and orthostatic positions (p N 0.05). At Post16, there was a significant decrease of the αLF during orthostatic stimulus compared to the supine position (p b 0.05). There was no significant difference between baseline and Post16 for αLF in supine position (p N 0.05). However, the αLF was lower at Post16 during orthostatic posture compared to the baseline (p b 0.05). The variation of αLF between supine and orthostatic postures (ΔαLF) was higher at Post16, compared to the baseline (ΔαLF baseline: -1.7 ± 3.5; Post16: -6.9 ± 5.7; p b 0.05). A 16-week hydrotherapy program improved the cardiac baroreflex control response to the orthostatic stimulus in women with FMS.

Background: Aging promotes increased levels of circulating proinflammatory markers and decrease in cardiac autonomic function that can be evaluated by high sensitivity C-reactive protein (hsCRP) and heart rate variability (HRV), respectively. Studies shown relation between the immune system and HRV, however, few studies are related to the baroreflex sensitivity (BRS). Aim: To evaluate the relationship between cardiovascular autonomic nervous system (BRS) and hsCRP in natural human aging in a wide range of age and gender. Methods: One hundred and ten apparently healthy individuals (without hsCRP values suggestive of acute inflammation, above 3.0 mg/L) were divided into 2 groups (men and women) and then, equally assigned into 5 groups (21-30; 31-40; 41-50; 51-60 and 61-70 years), 11 subjects in each group. The electrocardiographic, respiratory andnoninvasivefinger arterial pressure signalswere recorded for 15 minutes, in rest supine (REST) and in orthostatic position (STAND), and sampled at 400Hz. Stable sequences of 256 points in REST and STAND were chosen. Cross-spectral analysis was performed to compute coherence, phase and BRS in low (LF) frequency. Blood was collected after a 12-hour fasting. The turbidimetry method was used for hsCRP analysis. Results: Spearman correlation test showed a negative significant relationship (p b 0.05) between hsCRP and phase (r = -0.576) and between hsCRP and BRS (r = -0.356) in LF in STAND inwomen, however, no correlation was found in men. Conclusion: The relationship between proinflammatory marker and cardiovascular autonomic nervous system showed a gender dependency therefore gender should be taken into account in the analysis of the cardiovascular autonomic nervous system. Financial support: FAPESP: 2010/52070-4; CNPq: 311938/2013-2; CNPq: 140164/2015-4.

SummaryObjectiveThe purpose of present study was to evaluate the acute effects of bi-level positive airway pressure (BiPAP) on heart rate variability (HRV) of stable chronic obstructive pulmonary disease patients (COPD).MethodsNineteen males with COPD (69±8 years and with forced expiratory volume in 1s

CONTEXT AND OBJECTIVES: Respiratory muscle strength is relevant to the clinical situation of elderly patients, particularly those presenting with respiratory or cardiac diseases. The objectives of this study were to evaluate the respiratory muscle strength of institutionalized elderly women, compare this with predicted values for the Brazilian population and calculate the correlation with age and anthropometric characteristics. DESIGN AND SETTING: Cross-sectional study at the Department of Physiotherapy of Universidade Camilo Castelo Branco. METHODS: The participants were 56 institutionalized elderly women (74.87 ± 10.55 years of age), evaluated in eight institutions in three cities in the central region of the State of São Paulo, between January 2005 and March 2006. They were separated into three subgroups according to age: 60-69 years (n = 20), 70-79 (n = 18) and 80-89 years (n = 18). Maximal respiratory pressures were obtained using a manovacuometer. The values obtained were compared between subgroups and with predicted values. Correlation analysis was used to evaluate age, weight, height and body mass index in relation to maximal respiratory pressures. The significance level was P < 0.05. RESULTS: No significant differences in maximal respiratory pressures were seen between the three subgroups. The maximal respiratory pressures were significantly lower in the three subgroups, compared with predicted values. Negative correlations between maximal respiratory pressures and age and positive correlations in relation to weight, height and body mass index were found. CONCLUSIONS: Respiratory muscle strength was markedly reduced in institutionalized 60 to 89-year-old women and the values demonstrated correlations with age and anthropometric characteristics. CONTEXTO E OBJETIVOS: A força muscular respiratória é relevante para a situação clínica de pacientes idosos, particularmente os que apresentam doença cardíaca ou respiratória. Os objetivos deste estudo foram avaliar a força muscular respiratória de mulheres idosas asiladas, comparar com os valores preditos para a população brasileira e correlacioná-los com a idade e características antropométricas. TIPO DE ESTUDO E LOCAL: Estudo transversal desenvolvido pelo Departamento de Fisioterapia da Universidade Camilo Castelo Branco. MÉTODOS: Foram estudadas 56 mulheres idosas asiladas (74,87 ± 10,55 anos) sendo avaliadas em oito instituições em três cidades do interior do estado de São Paulo, entre janeiro de 2005 e março de 2006. Elas foram separadas em três subgrupos: de 60-69 anos (n = 20), de 70-79 anos (n = 18) e de 80-89 anos (n = 18). As pressões respiratórias máximas foram obtidas através de um manovacuômetro. Os valores obtidos foram comparados entre os subgrupos e também com os preditos para a população brasileira. Análise de correlação foi aplicada para a idade, peso, altura e índice de massa corpórea com os valores das pressões respiratórias máximas. O nível de significância adotado foi P < 0,05. RESULTADOS: Não houve diferenças significativas das pressões respiratórias máximas entre os três subgrupos. Em relação aos valores preditos, as pressões respiratórias máximas obtidas foram significativamente menores nos três subgrupos. Correlações negativas entre as pressões respiratórias máximas e a idade e positivas em relação ao peso, altura e índice de massa corpórea foram encontradas. CONCLUSÕES: A força muscular respiratória é marcantemente reduzida em idosas asiladas de 60 a 89 anos, havendo correlação das pressões respiratórias máximas com a idade e com as características antropométricas.

A crescente demanda pelo treinamento resistido tem incentivado a procura de metodologias para a prescrição deste tipo de exercício. Por isso, há uma busca incessante para se prescrever corretamente qual parâmetro e/ou intensidade seja a ideal para a execução do exercício resistido. Dessa forma protocolos incrementais podem ser interessantes, uma vez que podem determinar a magnitude das respostas fisiológicas (principalmente lactato e consumo de oxigênio) em diferentes domínios (leve, moderado e alto), pois através deles é possível identificar parâmetros de aptidão aeróbia e anaeróbia, como o limiar de lactato, limiar anaeróbio e carga crítica. No entanto, poucos estudos têm analisado de forma sistematizada diferentes intensidades de exercício resistido com o objetivo de determinar a magnitude das respostas cardiorrespiratórias, metabólicas e eletromiográficas para então propor estratégias reabilitadoras a indivíduos idosos baseada nestas respostas. Dessa forma, o objetivo principal desse estudo foi comparar as intensidades determinadas como limiar anaeróbio e carga crítica, em relação aos parâmetros de frequência cardíaca, ventilação, consumo de oxigênio, lactato, débito cardíaco, volume sistólico, além da análise eletromiográfica, entre jovens e idosos. Participaram deste estudo 35 homens ativos, sendo 20 jovens (média de idade de 23 ± 3 anos) e 15 idosos (média de idade de 70 ± 2,4 anos), aparentemente saudáveis. Todos os voluntários realizaram, de forma aleatória e em dias diferentes a: 1) teste de 1 RM em exercício resistido no Leg Press 45°; 2) teste de exercício físico resistido dinâmico crescente descontínuo; 3) três testes de exercícios resistidos de alta intensidade de carga constante (60%, 75% e 90% de 1 RM) até a fadiga e, após estes testes realizaram:, 4) teste de tolerabilidade no limiar anaeróbio, obtido através do teste crescente e, 5) teste de tolerabilidade da carga crítica obtida, pela regressão linear e relação hiperbólica entre carga e tempo de execução. Com relação ao limiar anaeróbio, obtido no teste incremental, foi possível determinar que este ocorreu em torno de 30% 1 RM e a carga crítica foi aproximadamente 52% 1 RM, para ambos os grupos. Com relação aos parâmetros estudados nas intensidades de exercício executadas, o envelhecimento mostrou ser determinante para uma redução nos valores relativos à capacidade aeróbia bem como na frequência cardíaca. Já com relação especificamente as intensidades do limiar anaeróbio e carga crítica, em ambos os grupos a ventilação, foi maior e consumo de oxigênio foi menor na intensidade da carga crítica. Já para as respostas de lactato, nós observamos menores valores para o grupo idoso, tanto para o limiar como na carga crítica. O débito cardíaco apresentou diferença apenas entre os grupos e não entre as intensidades, sendo que devido ao envelhecimento, houve redução dos valores. Já para a EMG, houve maiores quedas do slope da FM para idosos quando comparado aos jovens em 30%, e além disso, na intensidade de 30% acarretou em menor queda que em 52%. Ao comparar ao longo do tempo a FM e o RMS, o comportamento destes foi semelhantes nas duas intensidades, ou seja, de queda e aumento, respectivamente, o que é indicativo de maior fadigabilidade ao final do exercício. Além disso, a taxa de queda foi maior no grupo idoso, sendo que esse parâmetro é um indicador de maior fadiga muscular para este grupo. Entretanto, o comportamento do RMS ao final das duas intensidades foi menor nos idosos. Dessa forma, nossos resultados podem ter aplicações como uma forma de avaliar o desempenho funcional durante exercícios resistidos em diferentes populações e também pode ter utilidade na prescrição de um programa de treinamento dependo do objetivo a ser alcançado, elucidando a importância prática da aplicação de exercícios de resistência dinâmica. The increasing demand for resistance training has motivated the search methodologies for prescribing this type of exercise. Therefore, there is a constant search to correctly prescribe which parameter and/or intensity is ideal for the implementation of resistance exercise. Thus incremental protocols may be interesting, since they can determine the magnitude of physiological responses (mainly lactate and oxygen consumption) in different domains (mild, moderate and high), because it is possible through them to identify parameters of aerobic and anaerobic fitness as the lactate threshold, anaerobic threshold and critical load. However, few studies have examined systematically different resistance exercise intensities form in order to determine the magnitude of the cardiorespiratory, metabolic and electromyographic responses and then propose the elderly rehabilitation strategies based on these answers. Thus, the aim of this study was to compare the intensities determined as anaerobic threshold and critical load, with respect to heart rate parameters, ventilation, oxygen consumption, lactate, cardiac output, stroke volume, besides the electromyographic analysis, between young and senior citizens. The study included 35 active men, 20 young (mean age 23 ± 3 years) and 15 older adults (mean age 70 ± 2.4 years), apparently healthy. All volunteers pertormed randomly on different days to: 1) 1 RM test in resistance exercise in Leg Press 45º; 2) dynamic resistance exercise test growing discontinuous; 3) three tests of resistance exercise high intensity constant load (60%, 75% and 90% of 1 RM) to failure and after these tests, performed 4) tolerance test at the anaerobic threshold, obtained by increasing test, 5) tolerability test critical load obtained by linear regression and hyperbolic relationship between load and runtime. Regarding the anaerobic threshold obtained in the incremental test, was determined that this occurred around 30% 1 RM and the critical load was approximately 52% 1 RM for both groups. As for the parameters studied in the exercise intensities performed, aging proved to be decisive for a reduction in the relative values of aerobic capacity and heart rate. In relation specifically the intensities of the anaerobic threshold and critical load in both grups, ventilation was higher and oxygen consumption was lower in the intensity of the critical load. As for the lactate responses, we observed lower values for the elderly group, both the threshold and the critical load. Cardiac output was difference only between groups and not between the intensities, and due to aging, decreased the values. As for EMG, was greater MF of the slope falls to elderly compared to 30% in young, and furthermore, intensity of 30% fall which resulted in less by 52%. Comparing over time RMS and MF, was similar in behavior of the two intensities, ie, increase and decrease, respectively, which is indicative of greater fatigue at the end of exercise. Furthermore, the decrease rate was higher in the elderly group, and this parameter is an indicator of increased muscle fatigue for this group. However, RMS behavior at the end of the two intensities were lower in the elderly. Thus, our results may have applications as a way to evaluate the functional performance during resistance training in different populations and can also be useful in prescribing a training program depend on the objective to be achieved, explaining the practical importance of the application of resistance exercise dynamics.