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| Martinelli,F.S.; Chacon-Mikahil,M.P.T.; Martins,L.E.B.; Lima-Filho,E.C.; Golfetti,R.; Paschoal,M.A.; Gallo-Junior,L.. |
| The purpose of the present study was to determine if autonomic heart rate modulation, indicated by heart rate variability (HRV), differs during supine rest and head-up tilt (HUT) when sedentary and endurance-trained cyclists are compared. Eleven sedentary young men (S) and 10 trained cyclists (C) were studied. The volunteers were submitted to a dynamic ECG Holter to calculate HRV at rest and during a 70º HUT. The major aerobic capacity of athletes was expressed by higher values of <img src="/img/revistas/bjmbr/v38n4/Vo.gif">at anaerobic threshold and peak conditions (P < 0.05). At rest the athletes had lower heart rates (P < 0.05) and higher values in the time domain of HRV compared with controls (SD of normal RR interval, SDNN, medians): 59.1... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Endurance; Power spectral analysis; Heart rate variability; Autonomic heart rate modulation; Training bradycardia; Orthostatic stress. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000400019 |
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| Kunz,V.C.; Borges,E.N.; Coelho,R.C.; Gubolino,L.A.; Martins,L.E.B.; Silva,E.. |
| The objectives of this study were to evaluate and compare the use of linear and nonlinear methods for analysis of heart rate variability (HRV) in healthy subjects and in patients after acute myocardial infarction (AMI). Heart rate (HR) was recorded for 15 min in the supine position in 10 patients with AMI taking β-blockers (aged 57 ± 9 years) and in 11 healthy subjects (aged 53 ± 4 years). HRV was analyzed in the time domain (RMSSD and RMSM), the frequency domain using low- and high-frequency bands in normalized units (nu; LFnu and HFnu) and the LF/HF ratio and approximate entropy (ApEn) were determined. There was a correlation (P < 0.05) of RMSSD, RMSM, LFnu, HFnu, and the LF/HF ratio index with the ApEn of the AMI group on the 2nd (r = 0.87, 0.65,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Myocardial infarction; Heart rate variability; Autonomic nervous system; Spectral analysis; Nonlinear dynamics. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012000500011 |
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| Melo,R.C.; Santos,M.D.B.; Silva,E.; Quitério,R.J.; Moreno,M.A.; Reis,M.S.; Verzola,I.A.; Oliveira,L.; Martins,L.E.B.; Gallo-Junior,L.; Catai,A.M.. |
| The effects of the aging process and an active life-style on the autonomic control of heart rate (HR) were investigated in nine young sedentary (YS, 23 ± 2.4 years), 16 young active (YA, 22 ± 2.1 years), 8 older sedentary (OS, 63 ± 2.4 years) and 8 older active (OA, 61 ± 1.1 years) healthy men. Electrocardiogram was continuously recorded for 15 min at rest and for 4 min in the deep breathing test, with a breath rate of 5 to 6 cycles/min in the supine position. Resting HR and RR intervals were analyzed by time (RMSSD index) and frequency domain methods. The power spectral components are reported in normalized units (nu) at low (LF) and high (HF) frequency, and as the LF/HF ratio. The deep breathing test was analyzed by the respiratory sinus arrhythmia... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Heart rate variability; Respiratory sinus arrhythmia; Autonomic nervous system; Aging process; Aerobic exercise. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000900007 |
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| Chacon-Mikahil,M.P.T.; Forti,V.A.M.; Catai,A.M.; Szrajer,J.S.; Golfetti,R.; Martins,L.E.B.; Lima-Filho,E.C.; Wanderley,J.S.; Marin-Neto,J.A.; Maciel,B.C.; Gallo-Jr.,L.. |
| We investigated the effects of aerobic training on the efferent autonomic control of heart rate (HR) during dynamic exercise in middle-aged men, eight of whom underwent exercise training (T) while the other seven continued their sedentary (S) life style. The training was conducted over 10 months (three 1-h sessions/week on a field track at 70-85% of the peak HR). The contribution of sympathetic and parasympathetic exercise tachycardia was determined in terms of differences in the time constant effects on the HR response obtained using a discontinuous protocol (4-min tests at 25, 50, 100 and 125 watts on a cycle ergometer), and a continuous protocol (25 watts/min until exhaustion) allowed the quantification of the parameters (anaerobic threshold, VO2 AT;... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sympathetic modulation of heart rate; Dynamic exercise; Aerobic training; Autonomic nervous system; Anaerobic threshold; Middle-aged men. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000500016 |
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| Catai,A.M.; Chacon-Mikahil,M.P.T.; Martinelli,F.S.; Forti,V.A.M.; Silva,E.; Golfetti,R.; Martins,L.E.B.; Szrajer,J.S.; Wanderley,J.S.; Lima-Filho,E.C.; Milan,L.A.; Marin-Neto,J.A.; Maciel,B.C.; Gallo-Junior,L.. |
| 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... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heart rate variability; Power spectral density analysis; Anaerobic threshold; Aerobic exercise training; Autonomic nervous system and aging processes in man. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000600016 |
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| Neves,V.F.C.; Silva de Sá,M.F.; Gallo Jr.,L.; Catai,A.M.; Martins,L.E.B.; Crescêncio,J.C.; Perpétuo,N.M.; Silva,E.. |
| The aim of the present study was to determine whether estrogen therapy (ET) reduces alterations of the autonomic control of heart rate (HR) due to hypoestrogenism and aging. Thirteen young (24 ± 2.6 years), 10 postmenopausal (53 ± 4.6 years) undergoing ET (PM-ET), and 14 postmenopausal (56 ± 2.6 years) women not undergoing ET (PM) were studied. ET consisted of 0.625 mg/day conjugated equine estrogen. HR was recorded continuously for 8 min at rest in the supine and sitting positions. HR variability (HRV) was analyzed by time (SDNN and rMSSD indices) and frequency domain methods. Power spectral components are reported as normalized units (nu) at low (LF) and high (HF) frequencies, and as LF/HF ratio. Intergroup comparisons: SDNN index was higher in young... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heart rate variability; Aging; Menopause; Estrogen therapy. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2007000400007 |
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