ABSTRACT
OBJECTIVES: Misuse of anabolic androgenic steroids in athletes is a strategy used to enhance strength and skeletal muscle hypertrophy. However, its abuse leads to an imbalance in muscle sympathetic nerve activity, increased vascular resistance, and increased blood pressure. However, the mechanisms underlying these alterations are still unknown. Therefore, we tested whether anabolic androgenic steroids could impair resting baroreflex sensitivity and cardiac sympathovagal control. In addition, we evaluate pulse wave velocity to ascertain the arterial stiffness of large vessels. METHODS: Fourteen male anabolic androgenic steroid users and 12 nonusers were studied. Heart rate, blood pressure, and respiratory rate were recorded. Baroreflex sensitivity was estimated by the sequence method, and cardiac autonomic control by analysis of the R-R interval. Pulse wave velocity was measured using a noninvasive automatic device. RESULTS: Mean spontaneous baroreflex sensitivity, baroreflex sensitivity to activation of the baroreceptors, and baroreflex sensitivity to deactivation of the baroreceptors were significantly lower in users than in nonusers. In the spectral analysis of heart rate variability, high frequency activity was lower, while low frequency activity was higher in users than in nonusers. Moreover, the sympathovagal balance was higher in users. Users showed higher pulse wave velocity than nonusers showing arterial stiffness of large vessels. Single linear regression analysis showed significant correlations between mean blood pressure and baroreflex sensitivity and pulse wave velocity. CONCLUSIONS: Our results provide evidence for lower baroreflex sensitivity and sympathovagal imbalance in anabolic androgenic steroid users. Moreover, anabolic androgenic steroid users showed arterial stiffness. Together, these alterations might be the mechanisms triggering the increased blood pressure in this population.
Subject(s)
Humans , Male , Adult , Autonomic Nervous System/drug effects , Vagus Nerve/drug effects , Cardiovascular System/drug effects , Baroreflex/drug effects , Anabolic Agents/adverse effects , Androgens/adverse effects , Autonomic Nervous System/physiology , Blood Pressure/drug effects , Cardiovascular Physiological Phenomena/drug effects , Cross-Sectional Studies , Risk Factors , Baroreflex/physiology , Vascular Stiffness/drug effects , Pulse Wave AnalysisABSTRACT
Abstract Background: Endomyocardial fibrosis (EMF) is a rare disease, characterized by diastolic dysfunction which leads to reduced peak oxygen consumption (VO2). Cardiopulmonary exercise testing (CPET) has been proved to be a fundamental tool to identify central and peripheral alterations. However, most studies prioritize peak VO2 as the main variable, leaving aside other important CPET variables that can specify the severity of the disease and guide the clinical treatment. Objective: The aim of this study was to evaluate central and peripheral limitations in symptomatic patients with EMF by different CPET variables. Methods: Twenty-six EMF patients (functional class III, NYHA) were compared with 15 healthy subjects (HS). Functional capacity was evaluated using CPET and diastolic and systolic functions were evaluated by echocardiography. Results: Age and gender were similar between EMF patients and HS. Left ventricular ejection fraction was normal in EMF patients, but decreased compared to HS. Peak heart rate, peak workload, peak VO2, peak oxygen (O2) pulse and peak pulmonary ventilation (VE) were decreased in EMF compared to HS. Also, EMF patients showed increased Δ heart rate /Δ oxygen uptake and Δ oxygen uptake /Δ work rate compared to HS. Conclusion: Determination of the aerobic capacity by noninvasive respiratory gas exchange during incremental exercise provides additional information about the exercise tolerance in patients with EMF. The analysis of different CPET variables is necessary to help us understand more about the central and peripheral alterations cause by both diastolic dysfunction and restrictive pattern.
Resumo Fundamento: A endomiocardiofibrose (EMF) é uma doença rara, caracterizada por disfunção diastólica que leva à redução consumo de oxigênio (VO2) pico. O teste de esforço cardiopulmonar (TECP) tem se mostrado uma ferramenta fundamental na identificação de alterações centrais e periféricas. No entanto, a maioria dos estudos prioriza o VO2 pico como a variável principal, em detrimento de outras importantes variáveis do TECP que poderiam identificar a gravidade da doença e direcionar o tratamento clínico. Objetivo: O objetivo deste estudo foi avaliar limitações centrais e periféricas em pacientes com EMF sintomáticos por meio de variáveis do TECP. Métodos: Vinte e seis pacientes com EMF (classe funcional III, NYHA) foram comparados com 15 indivíduos controle saudáveis (CS). A capacidade funcional foi avaliada por TECP e funções sistólicas e diastólicas por ecocardiografia. Resultados: A idade e o gênero foram similares entre pacientes com EMF e CS. A fração de ejeção do ventrículo esquerdo foi normal em pacientes com EMF, porém diminuída em comparação aos CS. Os picos de frequência cardíaca, carga de trabalho, VO2, pulso de oxigênio (O2) e da ventilação pulmonar (VE) estavam diminuídos em pacientes com EMF em comparação aos CS. Ainda, os pacientes com EMF apresentaram Δ frequência cardíaca /Δ consumo de oxigênio e Δ consumo de oxigênio /Δ taxa de trabalho aumentados em comparação aos CS. Conclusão: A determinação da capacidade aeróbica por troca respiratória não invasiva durante exercício progressivo fornece informações sobre a tolerância ao exercício em pacientes com EMF. É necessária uma análise das diferentes variáveis do TECP para nos ajudar a compreender mais acerca das alterações centrais e periféricas causadas tanto pela disfunção diastólica como pelo padrão restritivo.