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Provedor de dados:  BJMBR
País:  Brazil
Título:  Effects of aerobic exercise training on heart rate variability during wakefulness and sleep and cardiorespiratory responses of young and middle-aged healthy men
Autores:  Catai,A.M.
Data:  2002-06-01
Ano:  2002
Palavras-chave:  Heart rate variability
Power spectral density analysis
Anaerobic threshold
Aerobic exercise training
Autonomic nervous system and aging processes in man
Resumo:  The purpose of the present study was to evaluate the effects of aerobic physical training (APT) on heart rate variability (HRV) and cardiorespiratory responses at peak condition and ventilatory anaerobic threshold. Ten young (Y: median = 21 years) and seven middle-aged (MA = 53 years) healthy sedentary men were studied. Dynamic exercise tests were performed on a cycloergometer using a continuous ramp protocol (12 to 20 W/min) until exhaustion. A dynamic 24-h electrocardiogram was analyzed by time (TD) (standard deviation of mean R-R intervals) and frequency domain (FD) methods. The power spectral components were expressed as absolute (a) and normalized units (nu) at low (LF) and high (HF) frequencies and as the LF/HF ratio. Control (C) condition: HRV in TD (Y: 108, MA: 96 ms; P<0.05) and FD - LFa, HFa - was significantly higher in young (1030; 2589 ms²/Hz) than in middle-aged men (357; 342 ms²/Hz) only during sleep (P<0.05); post-training effects: resting bradycardia (P<0.05) in the awake condition in both groups; VO2 increased for both groups at anaerobic threshold (P<0.05), and at peak condition only in young men; HRV in TD and FD (a and nu) was not significantly changed by training in either groups. The vagal predominance during sleep is reduced with aging. The resting bradycardia induced by short-term APT in both age groups suggests that this adaptation is much more related to intrinsic alterations in sinus node than in efferent vagal-sympathetic modulation. Furthermore, the greater alterations in VO2 than in HRV may be related to short-term APT.
Tipo:  Info:eu-repo/semantics/article
Idioma:  Inglês
Editor:  Associação Brasileira de Divulgação Científica
Relação:  10.1590/S0100-879X2002000600016
Formato:  text/html
Fonte:  Brazilian Journal of Medical and Biological Research v.35 n.6 2002
Direitos:  info:eu-repo/semantics/openAccess

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