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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.

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.

BACKGROUND: The analysis of the kinetic responses of heart rate (HR) and oxygen consumption (VO2) are an important tool for the evaluation of exercise performance and health status. OBJECTIVES: The purpose of this study was to investigate the effects of aging on the HR and VO2 kinetics during the rest-exercise transition (on-transient) and the exercise-recovery transition (off-transient), in addition to investigating the influence of exercise intensity (mild and moderate) on these variables. METHOD: A total of 14 young (23±3 years) and 14 elderly (70±4 years) healthy men performed an incremental exercise testing (ramp protocol) on a cycle-ergometer to determine the maximal power (MP). Discontinuous exercise testing was initiated at 10% of the MP with subsequent increases of 10% until exhaustion. The measurement of HR, ventilatory and metabolic variables and blood lactate were obtained at rest and during the discontinuous exercise. RESULTS: The lactate threshold was determined in each subject and was similar between the groups (30±7% of MP in the young group and 29±5% of MP in the elderly group, p>0.05). The HR and VO2 kinetics (on- and off-transient) were slower in the elderly group compared to the young group (p

OBJETIVO: Avaliar a modulação autonômica da frequência cardíaca (FC) em repouso, na postura supina e durante a manobra de acentuação da arritmia sinusal respiratória (M-ASR) de pacientes com doença pulmonar obstrutiva crônica (DPOC) ou com insuficiência cardíaca crônica (ICC). MÉTODOS: Vinte e oito homens foram subdivididos em três grupos: 10 com DPOC (GD) e 69±9 anos; 9 com ICC (GI) e 62±8 anos; e 9 saudáveis (GC) com 64±5 anos. Em repouso, os intervalos R-R a partir do sinal eletrocardiográfico foram obtidos nas seguintes situações: 1) 15 minutos na posição supina e 2) 4 minutos durante M-ASR na posição supina. Os dados foram analisados nos domínios do tempo (índices RMSSD e SDNN) e da frequência. Durante M-ASR, foram calculadas a razão expiração/inspiração (E/I) e a diferença inspiração/expiração (∆IE). RESULTADOS: Os principais achados mostraram que os pacientes com ICC apresentaram menores valores de RMSSD (12,2±2,6 vs 20,4±6,5), BFab (99,2±72,7 vs 305,3±208,9) e AFun (53,4±29,9 vs 178,9±113,1) quando comparados ao controle. Além disso, a banda de BFab foi significantemente reduzida no grupo DPOC quando comparado ao controle (133,8±145,5 vs 305,3±208,9). Adicionalmente, pacientes com ICC e DPOC mostraram menor razão E/I (1,1±0,06 vs 1,2±0,1 e 1,1±0,03 vs 1,2±0,1) e ∆IE (7,0±3,5 vs 12,7±0,1 e 4,9±1,6 vs 12,7±0,1), respectivamente, comparados ao GC durante a M-ASR. CONCLUSÃO: Os resultados deste estudo sugerem que tanto a DPOC como a ICC produzem impacto negativo sobre o controle autonômico da FC. Artigo registrado no Australian New Zealand Clinical Trials Registry (ANZCTR) sob o número: ACTRN12609000467235 OBJECTIVE: To evaluate the autonomic modulation of heart rate (HR) at rest in the supine position and during a respiratory sinus arrhythmia maneuver (M-RSA) among participants with chronic obstructive pulmonary disease (COPD) or with chronic heart failure (CHF). METHODS: Twenty-eight men were divided into three groups: ten with COPD, aged 69±9 years; nine with CHF, aged 62±8 years; and nine healthy participants aged 64±5 years (controls). At rest, the R-R interval of the electrocardiographic signal was obtained in the following situations: 1) 15 min in the supine position; and 2) 4 min during M-RSA in the supine position. The data were analyzed in the time domain (RMSSD and SDNN indices) and the frequency domain (LFab and HFab). During M-RSA, the expiratory/inspiratory ratio (E/I) and the inspiratory/expiratory difference (∆IE) were calculated. RESULTS: The main findings showed that the CHF patients presented lower RMSSD (12.2±2.6 vs. 20.4±6.5), LFab (99.2±72.7 vs. 305.3±208.9) and HFab (53.4±29.9 vs. 178.9±113.1), compared with the controls. The LFab band was significantly lower in the COPD group than in the controls (133.8±145.5 vs. 305.3±208.9). Additionally, both CHF patients and COPD patients showed lower E/I ratios (1.1±0.06 vs. 1.2±0.1 and 1.1±0.03 vs. 1.2±0.1) and ∆IE values (7.0±3.5 vs. 12.7±0.1 and 4.9±1.6 vs. 12.7±0.1), respectively, compared with the controls during M-RSA. CONCLUSION: The results from this study suggest that both COPD and CHF have a negative impact on the autonomic control of heart rate. Article registered on the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number: ACTRN12609000467235

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