Diferença na resposta da frequência cardíaca no início do exercício dinâmico entre corredores de endurance e praticantes de exercícios resistidos intensos

• Autor(a) principal: Zaniqueli, Divanei dos Anjos
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/7965
• topic: Endurance runners; Resistance training practitioners; Heart rate increase in the onset of exercise; Corredores de endurance; Praticantes de exercício resistido intenso; Elevação da frequência cardíaca no início do exercício; Fisiologia; 612

Introduction: There are noticeable distinctions between endurance running and intensive resistance training. While endurance training running yields cardiovascular volume overload, intensive resistance training induces pressure overload. Both volume and pressure overload cause structural and functional adaptations in heart and blood vessels. Cardiac autonomic adaptations in endurance runners (ER) and intensive resistance training practitioners (IRT) have been investigated with heart rate variability (HRV). The rapid response of heart rate (HR) acceleration in the onset of muscular exercise could identify early impairments in the autonomic control of the cardiac function. Cardiac acceleration in the onset of dynamic physical exercise has not been compared between ER and IRT practitioners. Objectives: We sought to evaluate the HRV at time and frequency domain indexes and the Cardio-Vagal Index (CVI) in endurance runners, intensive resistance training practitioners and healthy sedentary men. Methods: ER (n= 21), IRT (n= 19) and a healthy control group (CON= 30) were selected as a subgroup from the database of ESCHOT study. HRV at time and frequency domain indices were used as parameters of HR vagal control, while CVI from four seconds exercise test (T4s) was used as an indicator of autonomic response magnitude to a physiologic stress. Results: The resting bradycardia was larger in ER than in IRT (ER: 55 ± 8 bpm; IRT: 61 ± 9 bpm, P<0.05); CVI was not different between groups (ER: 1.28 ± 0.15; IRT: 1.33 ± 0.16; CON: 1.28 ± 0.14, P= 0.49); the HR achieved at four second of exercise was lower in ER than in the other two groups (ER: 73 ± 13 bpm, IRT: 85 ± 15 bpm, CON: 93 ± 11 bpm, P<0.05), unlike the percent increase of HR at the exercise was equal between groups; the HF index of HRV, indicator of HR vagal control was larger in ER compared to IRT and CON (ER: 28.22; IRT: 8.85; CON: 11.40, P<0.05). Conclusion: Largest cardiac vagal tonus recorded in ER is not associated to CVI. The CVI value seems not to indicate vagal tonus, but HR achieved at four second of exercise might provide helpful information on adaptations in intrinsic HR and in cardiac autonomic control with long term endurance running.