Marcel da Rocha Chehuen

Cardiac Work Remains High after Strength Exercise in Elderly

Moderate- to high-intensity strength training is recommended for healthy adults. In young subjects, a single session of strength training decreases blood pressure, while heart rate and cardiac work remain elevated afterwards. However, these effects have not been clearly demonstrated in elderly subjects. To investigate this issue, 16 elderly subjects each underwent a Control and an Exercise (3 sets, 8 RM, 9 exercises) session conducted in random order. Haemodynamic variables and heart rate variability were measured before and after the interventions. Systolic blood pressure did not change after the exercise session but did increase after the control session (+8.1±1.6 mm Hg, P≤0.05). Diastolic blood pressure, as well as systemic vascular resistance increased similarly after both sessions. Cardiac output and stroke volume decreased, while heart rate, rate-pressure product and the low- to high-frequency ratio of heart rate variability increased only after the exercise session ( - 0.5±0.1 L/min, - 9.3±2.0 ml,+3.8±1.6 bpm, +579.3±164.1 mmHg.bpm and +0.71±0.34, P≤0.05). Ambulatory blood pressure was similar after both sessions, while heart rate and rate pressure product remained higher after the exercise session for up to 4.5 h. After a single session of strength training, cardiac sympathetic modulation and heart rate remain elevated in elderly subjects, keeping cardiac work elevated for a long period of time.

Post-walking Exercise Hypotension in Patients with Intermittent Claudication

PURPOSE This study aimed to investigate the acute effect of intermittent walking exercise (WE) on blood pressure (BP) responses in patients with intermittent claudication (IC). Secondly, this study aimed to gain improved insight into the physiological mechanisms controlling BP regulation after intermittent WE in this patient group. METHODS Twenty patients with IC participated in two experimental sessions in a random order, as follows: WE (15 × 2-min bouts of WE interpolated with 2-min rest intervals) and control (standing rest on a treadmill for 60 min). BP, cardiac output (CO: CO2 rebreathing), and cardiovascular autonomic modulation (spectral analysis of HR variability) were assessed before and after both experimental sessions during supine rest, and stroke volume (SV) and systemic vascular resistance (SVR) were calculated. Data were analyzed using two-way ANOVA. RESULTS WE decreased systolic, diastolic, and mean BP, with net effects of -13 ± 2, -5 ± 2, and -7 ± 2 mm Hg versus control, respectively (all P < 0.05). WE also decreased SV (-5.62 ± 1.97 mL, P < 0.05) and CO (-0.05 ± 0.13 L·min(-1), P < 0.05) versus preintervention and prevented the observed increase in SVR in the control condition (+4.2 ± 1.4 U, P < 0.05). HR showed a decrease (P < 0.05), consistent with evidence of increased vagal modulation, in the control condition. BP measurements over the subsequent 24 h were similar between experimental conditions. CONCLUSIONS In patients with IC, WE induced a postexercise hypotension response that had a significant magnitude versus control but was not maintained over the next 24 h of daily activities. The acute postexercise hypotension response was mediated by a decrease in CO and SV, which was not compensated by an augmentation of SVR, as observed in the control arm of the study.

Effects of oral N-acetylcysteine on walking capacity, leg reactive hyperemia, and inflammatory and angiogenic mediators in patients with intermittent claudication

Increased oxidative stress and inflammation contribute to impaired walking capacity and endothelial dysfunction in patients with intermittent claudication (IC). The goal of the study was to determine the effects of oral treatment with the antioxidant N-acetylcysteine (NAC) on walking capacity, leg postocclusive reactive hyperemia, circulating levels of inflammatory mediators, and whole blood expression of angiogenic mediators in patients with IC. Following a double-blinded randomized crossover design, 10 patients with IC received NAC (1,800 mg/day for 4 days plus 2,700 mg before the experimental session) and placebo (PLA) before undergoing a graded treadmill exercise test. Leg postocclusive reactive hyperemia was assessed before and after the test. Blood samples were taken before and after NAC or PLA ingestions and 5 and 30 min after the exercise test for the analysis of circulating inflammatory and angiogenic markers. Although NAC increased the plasma ratio of reduced to oxidized glutathione, there were no differences between experimental sessions for walking tolerance and postocclusive reactive hyperemia. Plasma concentrations of soluble vascular cell adhesion protein-1, monocyte chemotactic protein-1, and endothelin-1 increased similarly following maximal exercise after PLA and NAC (P < 0.001). Whole blood expression of pro-angiogenic microRNA-126 increased after maximal exercise in the PLA session, but treatment with NAC prevented this response. Similarly, exercise-induced changes in whole blood expression of VEGF, endothelial nitric oxide synthase and phosphatidylinositol 3-kinase R2 were blunted after NAC. In conclusion, oral NAC does not increase walking tolerance or leg blood flow in patients with IC. In addition, oral NAC prevents maximal exercise-induced increase in the expression of circulating microRNA-126 and other angiogenic mediators in patients with IC.

Predictors of walking capacity in peripheral arterial disease patients

OBJECTIVE: To estimate walking capacity in intermittent claudication patients through a prediction model based on clinical characteristics and the walking impairment questionnaire. METHODS: The sample included 133 intermittent claudication patients of both genders aged between 30 and 80 years. Data regarding clinical characteristics, the walking impairment questionnaire and treadmill walking test performance were obtained. Multiple regression modeling was conducted to predict claudication onset distance and total walking distance using clinical characteristics (age, height, mass, body mass index, ankle brachial index lower, gender, history of smoking and co-morbid conditions) and walking impairment questionnaire responses. Comparisons of claudication onset distance and total walking distance measured during treadmill tests and estimated by a regression equation were performed using paired t-tests. RESULTS: Co-morbid conditions (diabetes and coronary artery disease) and questions related to difficulty in walking short distances (walking indoors – such as around your house and walking 5 blocks) and at low speed (walking 1 block at average speed – usual pace) resulted in the development of new prediction models high significant for claudication onset distance and total walking distance (p<0.001). In addition, non-significant differences from the results obtained by the treadmill test and estimated by the current model (p>0.05) were observed. CONCLUSION: The current study demonstrated that walking capacity can be adequately estimated based on co-morbid conditions and responses to the walking impairment questionnaire.

Exercise prescription using the heart of claudication pain onset in patients with intermittent claudication

OBJECTIVE: To assess the acute metabolic and cardiovascular responses to walking exercise at an intensity corresponding to the heart rate of claudication pain onset and to investigate the effects of a 12-week walking training program at this intensity on walking capacity. METHODS: Twenty-nine patients with intermittent claudication were randomly allocated to the walking training (n = 17) or control (CO, n = 12) group. The walking training group performed an acute exercise session comprising 15×2-min bouts of walking at the heart rate of claudication pain onset, with 2-min interpolated rest intervals. The claudication symptoms and cardiovascular and metabolic responses were evaluated. Walking training was then performed at the same intensity twice each week for 12 weeks, while the control group engaged in twice weekly stretching classes. The claudication onset distance and total walking distance were evaluated before and after the interventions. Brazilian Registry Clinical Trials: RBR-7M3D8W. RESULTS: During the acute exercise session, the heart rate was maintained within tight limits. The exercise intensity was above the anaerobic threshold and >80% of the heart rate peak and VO2peak. After the exercise training period, the walking exercise group (n = 13) showed increased claudication onset distance (309±153 vs. 413±201m) and total walking distance (784±182 vs. 1,100±236m) compared to the control group (n = 12) (p<0.05). CONCLUSION: Walking exercise prescribed at the heart rate of claudication pain onset enables patients with intermittent claudication to exercise with tolerable levels of pain and improves walking performance.

Risco cardiovascular e prática de atividade física em crianças e adolescentes de Muzambinho/MG: influência do gênero e da idade

INTRODUCTION AND OBJECTIVE: Cardiovascular disease begins at infancy and it has been linked to the presence of cardiovascular risk factors (CRF). Prevalence of these factors varies a lot among different Brazilian populations and has been mostly studied in big and medium size cities. Thus, this study assessed the prevalence of CRF and physical activity (PA) in children and adolescents from Muzambinho, a small city in the state of Minas Gerais. METHODS: 205 subjects (7 to 18 years - 108 males) were studied. Body weight and height, glycemia, cholesterolemia, blood pressure (BP), and PA were measured. Comparisons were made by Qui-square test. RESULTS: Obesity and altered values of BP, glycemia, and cholesterolemia were found, respectively, in 19, 11, 5 and 15% of the subjects. There was no difference between genders, while the prevalence of smokers, drinkers, altered BP, and inactivity increased with age. Seventy-nine percent of the subjects practiced community PA; 10% occupational PA; 97% physical education classes; 72% PA during school recess; and 90% leisure time PA. Ninety-two percent of them were active. Occupational PA was higher in girls, and increased with age in boys. Leisure time and during school recess PA decreased with age in both genders. CONCLUSION: Except for physical inactivity, prevalence of CRF was high, did not differ between genders, and increased with age. High levels of all kinds of PA were found; they differed between genders, and decreased with age.

Effects of Clustered Comorbid Conditions on Walking Capacity in Patients with Peripheral Artery Disease

BACKGROUND Comorbid conditions are known to increase cardiovascular risk in patients with peripheral artery disease (PAD). However, whether comorbid conditions affect walking capacity remains controversial. Previous studies have analyzed comorbidities separately, but they are known to occur in a clustered fashion in PAD patients. Therefore, the aim of this study was to analyze the influence of clustered comorbid conditions on walking capacity in PAD patients. METHODS This cross-sectional study included 415 PAD patients (155 women and 260 men with an average age of 63 years). Claudication distance and total walking distance were assessed with the graded maximal treadmill test. Medical histories of hypertension, diabetes, cerebrovascular disease (CVD), coronary artery disease (CAD), and chronic obstructive pulmonary disease (COPD) were obtained. Binary logistic regression was carried out to analyze whether clustered comorbid conditions were associated with walking capacity. RESULTS CVD was associated with lower total walking distance (odds ratio [OR] = 2.45; 95% confidence interval [CI]: 1.11-5.39). The cluster hypertension, diabetes, CVD, CAD, and COPD were associated with a lower claudication distance (OR = 7.63; 95% CI: 1.42-40.96). In addition, the clusters of CVD and hypertension (OR = 3.16; 95% CI: 1.38-7.23), CVD and CAD (OR = 3.46; 95% CI: 1.25-9.57), CVD, hypertension, and diabetes (OR = 11.38; 95% CI: 2.27-57.00) were associated with a lower total walking distance. CONCLUSIONS CVD was associated with walking impairment of IC patients and in particular when CVD is clustered with other comorbid conditions.

Stages of health behavior change and factors associated with physical activity in patients with intermittent claudication

OBJECTIVE To analyze, in people with intermittent claudication, the frequency of individuals who are in each of stages of health behavior change to practice physical activity, and analyze the association of these stages with the walking capacity. METHODS We recruited 150 patients with intermittent claudication treated at a tertiary center, being included those > 30-year-old-individuals and who had ankle-arm index < 0.90. We obtained socio-demographic information, presence of comorbidities and cardiovascular risk factors and stages of health behavior change to practice physical activity through a questionnaire, they being pre-contemplation, contemplation, preparation, action and maintenance. Moreover, the walking capacity was measured in a treadmill test (Gardner protocol). RESULTS Most individuals were in the maintenance stage (42.7%), however, when the stages of health behavior change were categorized into active (action and maintenance) and inactive (pre-contemplation, contemplation and preparation), 51.3% of the individuals were classified as inactive behavior. There was no association between stages of health behavior change, sociodemographic factors and cardiovascular risk factors. However, patients with intermittent claudication who had lower total walking distance were three times more likely to have inactive behavior. CONCLUSION Most patients with intermittent claudication showed an inactive behavior and, in this population, lower walking capacity was associated with this behavior.

Comparação entre os métodos subjetivo e objetivo para avaliação da capacidade funcional durante tratamento clínico em pacientes com claudicação intermitente

ABSTRACT Objective To analyze if there is any relation between functional capacity assessed by subjective and objective methods regarding the current state and after clinical treatment in patients with intermittent claudication. Methods A total of 500 patients with intermittent claudication were enrolled. All patients underwent clinical examination and a functional evaluation by subjective (clinical visit) and objective method (treadmill test). Additionally, 50 patients were selected to evaluate the effect of clinical treatment by subjective and objective methods in relation to functional capacity. Results Out of 500 patients, only 60 (12.0%) had similar results in both methods. The remaining, that is 440 patients (88.0%) had subject values in disagreement with stress test findings. Regarding the clinical effect of the treatment on the functional outcomes, results were similar in both methods (χ2=1.7; p=0.427). Conclusion Although the subjective method overestimates the functional capacity when compared to the objective method, no significant differences were observed between both methods when analyzing the effect of clinical treatment. Thus, the subjective method provides similar information as compared with objective method, in monitoring the clinical treatment of patients with intermittent claudication.

Relationship between walking capacity and ambulatory blood pressure in patients with intermittent claudication

Objective Patients with intermittent claudication (IC) often have high blood pressure (BP), which increases their cardiovascular risk. However, whether walking capacity is associated with BP levels in patients with IC remains unknown. Therefore, this study was designed to investigate whether the total walking distance is associated with ambulatory BP in patients with IC. Participants and methods This was a cross-sectional study of 75 patients with IC (58 men; 17 women). A maximal treadmill test (Gardner protocol) was performed to assess total walking distance in these patients. Furthermore, ambulatory BP, heart rate, rate–pressure product, and BP load were obtained over a 24-h period. One-way analysis of variance and multiple linear regression were carried out. Results Walking capacity was correlated negatively with the following: (i) asleep systolic BP, diastolic BP, mean BP and heart rate; (ii) 24-h, awake and asleep RPP; and (iii) awake and asleep systolic BP load (all P<0.05). These associations occurred irrespective of confounders such as age, sex, BMI, smoking status, and number of antihypertensive medications. Conclusion A better walking capacity is associated with lower ambulatory BP parameters in patients with IC.