BackgroundThe study was conducted to determine the impact of chronic obstructive pulmonary disease (COPD) in association with obstructive sleep apnea syndrome (OSAS) on cardiac autonomic control and functional capacity.Subjects and methodsThe study was a cross-sectional prospective controlled clinical study. Heart rate variability indices of 24 COPD (n = 12) and COPD+OSAS (n = 12) patients were evaluated and compared by electrocardiographic recordings acquired during rest, active postural maneuver (APM), respiratory sinus arrhythmia maneuver (RSA-m), and the 6-minute walk test (6MWT).ResultsThe COPD group presented higher parasympathetic modulation during APM when compared to the COPD+OSAS group (P = 0.02). The COPD+OSAS group presented higher sympathetic modulation during RSA-m when compared to the COPD group (P = 0.00). The performance during 6MWT was similarly impaired in both groups, despite the greater severity of the COPD group.ConclusionSubjects with COPD+OSAS present marked sympathetic modulation, and the presence of OSAS in COPD subjects has a negative impact on functional capacity regardless of the severity of lung disease.

Introduction: It is well known that type 2 diabetes mellitus (T2DM) produces cardiovascular autonomic neuropathy (CAN), which may affect the cardiac autonomic modulation. However, it is unclear whether the lack of glycemic control in T2DM without CAN could impact negatively on cardiac autonomic modulation. Objective: To evaluate the relationship between glycemic control and cardiac autonomic modulation in individuals with T2DM without CAN. Descriptive, prospective and cross sectional study. Methods: Forty-nine patients with T2DM (51±7 years) were divided into two groups according to glycosylated hemoglobin (HbA1c): G1≤7% and G2>7.0%. Resting heart rate (HR) and RR interval (RRi) were obtained and calculated by linear (Mean iRR; Mean HR; rMSSD; STD RR; LF; HF; LF/HF, TINN and RR Tri,) and non-linear (SD1; SD2; DFα1; DFα2, Shannon entropy; ApEn; SampEn and CD) methods of heart rate variability (HRV). Insulin, HOMA-IR, fasting glucose and HbA1c were obtained by blood tests. Results: G2 (HbA1c≤7%) showed lower values for the mean of iRR; STD RR; RR Tri, TINN, SD2, CD and higher mean HR when compared with G1 (HbA1c > 7%). Additionally, HbA1c correlated negatively with mean RRi (r=0.28, p=0.044); STD RR (r=0.33, p=0.017); RR Tri (r=-0.35, p=0.013), SD2 (r=-0.39, p=0.004) and positively with mean HR (r=0.28, p=0.045). Finally, fasting glucose correlated negatively with STD RR (r=-0.36, p=0.010); RR Tri (r=-0.36, p=0.010); TINN (r=-0.33, p=0.019) and SD2 (r=-0.42, p=0.002). Conclusion: We concluded that poor glycemic control is related to cardiac autonomic modulation indices in individuals with T2DM even if they do not present cardiovascular autonomic neuropathy.

Background: Recent evidence has indicated a ceiling to the benefits of exercise training that, if chronically surpassed, may have a negative effect on cardiac function. Conversely, improvements in peripheral arterial function may respond positively to chronic high volume training. Recent studies have shown that flow-mediated dilation (FMD) is decreased immediately after maximal exercise in sedentary subjects and is unaltered in subjects who participate in moderate volume exercise. We investigated the acute effects of maximal exercise on vascular function of elite female athletes with a high-volume training history. Methods: Fifteen elite female soccer players (mean age: 22.1 ± 4.4 years; BMI: 20.76 ± 1.75 kg/m2), with a high volume/intensity training history (4-6 hours per day) were evaluated. Subjects underwent maximal cardiopulmonary exercise testing (CPX) on a treadmill (VO2max 41.1 ± 3.9 mLO2•kg-1•min-1). Brachial artery FMD was determined using high-resolution ultrasound before and immediately after CPX. Flow velocity were measured at baseline (BSL) and during reactive hyperemia (RH) both prior to and following exercise. Results: Brachial artery diameter increased during RH before (3.42 ± 0.38mm vs. 3.03 ± 0.28mm, p<0.001) and after CPX (3.61 ± 0.44mm vs. 3.10 ± 0.37mm, p<0.001). Importantly, FMD was increased following CPX compared to BSL (16.86 ± 9.04% vs. 12.95 ± 7.03%, p=0.027). There was significant increase in peak flow velocity during RH before (135.28 ± 42.19cm/s vs. 79.19 ± 28.14cm/s, p=0.001) and after CPX (139.15 ± 41.07cm/s vs. 87.64 ± 21.23cm/s, p<0.001) (Table). Conclusion: The results of the current study indicate that arterial function is improved following acute aerobic exercise in elite female athletes with a chronic high volume training history. These findings deviate from the emerging literature suggesting chronic high volume training may be detrimental to cardiovascular function in the long term.

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