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D'Ascenzi F, Solari M, Anselmi F, Valentini F, Barbati R, Palmitesta P, Focardi M, Bonifazi M, Mondillo S. Electrocardiographic Changes Induced by Endurance Training and Pubertal Development in Male Children. Am J Cardiol 2017; 119:795-801. [PMID: 28034442 DOI: 10.1016/j.amjcard.2016.11.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/03/2016] [Accepted: 11/03/2016] [Indexed: 10/20/2022]
Abstract
Training-induced electrocardiographic changes are common in adult athletes. However, a few data are available on electrocardiogram (ECG) in preadolescent athletes and little is known about the potential changes induced by training on 12-lead electrocardiogram (ECG) at rest. Twelve-lead ECGs at rest and complete echocardiographic examinations were performed in 94 children (57 endurance athletes, 37 sedentary controls; mean age 10.8 ± 0.2 and 10.2 ± 0.2 years, respectively) at baseline and after 5 months of growth and training in athletes and of natural growth in controls. At baseline, athletes had lower heart rate at rest compared with controls (p = 0.046) and a further decrease was observed after training (p <0.0001). An incomplete right bundle branch block was found in 19% of athletes and 15% of controls (p = 0.69) with no changes after training. Although none of the athletes showed negative T waves from V1 to V3, 6% of controls at baseline had T-wave inversion V1 to V3 with a decrease to 3% after 5 months (p = 0.16). The early repolarization pattern did not differ between athletes and controls and was correlated with Tanner's scale score in the overall population both at first and second evaluation (R = 0.30, R = 0.27, p = 0.005, p = 0.012, respectively). No correlations were found between ECG and echocardiographic data. In conclusion, 12-lead ECG at rest is not substantially affected by training in children, despite a physiological increase in cavity size. Thus, in preadolescent athletes, 12-lead ECG at rest does not reflect exercise-induced morphologic remodeling and seems to be influenced more by sexual maturation than by training.
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Sala R, Malacarne M, Pagani M, Lucini D. Evidence of increased cardiac parasympathetic drive in subjects meeting current physical activity recommendations. Clin Auton Res 2015; 25:285-91. [PMID: 26359269 DOI: 10.1007/s10286-015-0300-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 05/13/2015] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Aerobic fitness seems to provide extra protection to the cardiovascular system beyond changing the traditional risk factors, a phenomenon referred to as the risk factor gap model. Aerobic fitness may possibly lead to improved autonomic regulation. The Task Force of the American Heart Association supports a national campaign to reach specific cardiovascular health goals considering various metrics, including recommended physical activity (PA) volumes. It may be clinically relevant to assess whether autonomic remodeling occurs in those who adhere to the PA recommendations. METHODS We studied 39 healthy subjects (22 males and 17 females), subdivided into two groups, according to whether they were meeting or not meeting PA recommendations (150 min/week of moderate aerobic activity, or 75 min/week of vigorous aerobic activity, or a combination of both). For each group, we evaluated aerobic capacity (VO2 Peak), body composition (Fat Mass) and autonomic nervous system profile, by way of mono and bivariate spectral analysis of cardiovascular beat by beat variability. RESULTS Subjects following PA recommendations show higher RR period, higher RR variance, greater absolute power of the respiratory component of RR variability (HFRR) and higher index alpha (a measure of spontaneous baroreflex). Moreover, as expected, the group that was meeting or exceeding current PA recommendations had higher VO2 peak, less fat mass and greater weekly energy expenditure. CONCLUSION Data show that subjects meeting current PA recommendations present a phenotype suggestive of enhanced parasympathetic drive to the SA node. This finding is compatible with the hypothesis that a more favorable autonomic profile is part of the mechanisms of the risk factor gap.
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Affiliation(s)
- Roberto Sala
- University of Milan, Milan, Italy.,Exercise Medicine Unit, Humanitas Clinical and Research Center, Via Alessandro Manzoni, 56, 20089, Rozzano, Milan, Italy
| | - Mara Malacarne
- Exercise Medicine Unit, Humanitas Clinical and Research Center, Via Alessandro Manzoni, 56, 20089, Rozzano, Milan, Italy.,Biometra Department, University of Milan, Milan, Italy
| | | | - Daniela Lucini
- Exercise Medicine Unit, Humanitas Clinical and Research Center, Via Alessandro Manzoni, 56, 20089, Rozzano, Milan, Italy. .,Biometra Department, University of Milan, Milan, Italy.
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Billman GE, Cagnoli KL, Csepe T, Li N, Wright P, Mohler PJ, Fedorov VV. Exercise training-induced bradycardia: evidence for enhanced parasympathetic regulation without changes in intrinsic sinoatrial node function. J Appl Physiol (1985) 2015; 118:1344-55. [PMID: 25749448 PMCID: PMC4451292 DOI: 10.1152/japplphysiol.01111.2014] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/28/2015] [Indexed: 01/17/2023] Open
Abstract
The mechanisms responsible for exercise-induced reductions in baseline heart rate (HR), known as training bradycardia, remain controversial. Therefore, changes in cardiac autonomic regulation and intrinsic sinoatrial nodal (SAN) rate were evaluated using dogs randomly assigned to either a 10- to 12-wk exercise training (Ex, n = 15) or an equivalent sedentary period (Sed, n = 10). Intrinsic HR was revealed by combined autonomic nervous system (ANS) blockade (propranolol + atropine, iv) before and after completion of the study. At the end of the study, SAN function was further evaluated by examining the SAN recovery time (SNRT) following rapid atrial pacing and the response to adenosine in anesthetized animals. As expected, both the response to submaximal exercise and baseline HR significantly (P < 0.01) decreased, and heart rate variability (HRV; e.g., high-frequency R-R interval variability) significantly (P < 0.01) increased in the Ex group but did not change in the Sed group. Atropine also induced significantly (P < 0.01) greater reductions in HRV in the Ex group compared with the Sed group; propranolol elicited similar HR and HRV changes in both groups. In contrast, neither intrinsic HR (Ex before, 141.2 ± 6.7; Ex after, 146.0 ± 8.0 vs. Sed before, 143.3 ± 11.1; Sed after, 141.0 ± 11.3 beats per minute), the response to adenosine, corrected SNRT, nor atrial fibrosis and atrial fibrillation inducibility differed in the Ex group vs. the Sed group. These data suggest that in a large-animal model, training bradycardia results from an enhanced cardiac parasympathetic regulation and not from changes in intrinsic properties of the SAN.
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Affiliation(s)
- George E Billman
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio; and
| | - Kristen L Cagnoli
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Thomas Csepe
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Ning Li
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Patrick Wright
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio; and
| | - Peter J Mohler
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio; and Deaprtment of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - Vadim V Fedorov
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio; and
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Singhal V, de Lourdes Eguiguren M, Eisenbach L, Clarke H, Slattery M, Eddy K, Ackerman KE, Misra M. Body composition, hemodynamic, and biochemical parameters of young female normal-weight oligo-amenorrheic and eumenorrheic athletes and nonathletes. ANNALS OF NUTRITION AND METABOLISM 2014; 65:264-71. [PMID: 25376841 DOI: 10.1159/000366024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/17/2014] [Indexed: 11/19/2022]
Abstract
AIMS Low-weight hypogonadal conditions such as anorexia nervosa are associated with marked changes in body composition, hemodynamic and hematological parameters, and liver enzymes. The impact of athletic activity in normal-weight adolescents with/without amenorrhea on these parameters has not been assessed. Our aim was to examine these parameters in normal-weight athletes and nonathletes and determine any associations with body composition, oligo-amenorrhea, and exercise intensity. METHODS We assessed vital signs, complete blood counts, liver enzymes, and regional body composition in 43 oligo-amenorrheic athletes (OAA), 24 eumenorrheic athletes (EA), and 23 nonathletes aged 14-21 years. RESULTS The BMI was lower in OAA than in EA. Systolic and pulse pressure and temperature were lowest in OAA. Blood counts did not differ among groups. Aspartate aminotransferase (AST) was higher in both groups of athletes, while alanine aminotransferase (ALT) was higher in OAA than in EA and nonathletes. Total and regional fat were lower in OAA than in other groups, and these factors were associated positively with heart rate and inversely with liver enzymes. CONCLUSIONS Athletic activity is associated with higher AST levels, whereas menstrual dysfunction is associated with lower total and regional fat and higher ALT levels. Higher liver enzymes are associated with reductions in total and regional fat.
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Affiliation(s)
- Vibha Singhal
- Neuroendocrine Unit, Massachusetts General Hospital, Boston, Mass., USA
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Breathing frequency-independent effect of Tai Chi Chuan on autonomic modulation. Clin Auton Res 2014; 24:47-52. [PMID: 24509942 DOI: 10.1007/s10286-014-0224-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 01/18/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE This study investigates the breathing frequency (BF)-independent effect of Tai Chi Chuan (TCC) on autonomic nervous modulation in TCC practitioners. METHODS Twenty-five TCC practitioners and 25 sedentary normal controls were recruited. The stationary heart rate variability (HRV) measures of TCC practitioners and controls were compared. The same HRV measures in TCC practitioners and among the controls, TCC practitioners before TCC and TCC practitioners 30 min after TCC were compared. RESULTS In TCC practitioners, the BF, normalized high-frequency power (nHFP), and normalized very low-frequency power were significantly increased, while the normalized low-frequency power (nLFP) was significantly decreased 30 min after TCC. The BF correlated significantly and negatively with heart rate (HR), nHFP and nLFP, and correlated significantly and positively with mean RR interval (MnRR) before TCC in TCC practitioners. A slower BF is associated with a higher HR, a greater vagal modulation, and a greater combined sympatho-vagal modulation before TCC. To remove the effect of BF on HRV measures, new indices such as HR*BF, nHFP*BF, nLFP*BF, and MnRR/BF were introduced for comparison among the controls, TCC practitioners before TCC, and TCC practitioners 30 min after TCC. Thirty minutes after TCC, the MnRR/BF of TCC practitioner was smaller whereas HR*BF and nHFP*BF were greater than those before TCC. INTERPRETATION The BF-independent effects of TCC on the autonomic nervous modulation of TCC practitioners are an increase in vagal modulation and HR, and a decrease in mean RR interval. The mechanism underlying the parallel increase in HR and vagal modulation in TCC practitioners is not understood yet at present.
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Chiu SN, Lin LY, Wang JK, Lu CW, Chang CW, Lin MT, Hua YC, Lue HC, Wu MH. Long-term outcomes of pediatric sinus bradycardia. J Pediatr 2013; 163:885-9.e1. [PMID: 23623512 DOI: 10.1016/j.jpeds.2013.03.054] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 03/04/2013] [Accepted: 03/19/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVES To delineate the long-term outcomes and mechanisms of pediatric sinus bradycardia. STUDY DESIGN Participants with sinus bradycardia who were identified from a survey of 432,166 elementary and high school students, were enrolled 10 years after the survey. The clinical course, heart rate variability, and hyperpolarization-activated cyclic nucleotide-gated potassium channel 4 (HCN4) gene were assessed. RESULTS A total of 104 (male:female was 60:44; prevalence, 0.025%) participants were observed to have sinus bradycardia at age 15.5 ± 0.2 years with a mean heart rate of 48.4 ± 0.4 beats per minute; 86 study participants (83%) responded to clinical assessment and 37 (36%) underwent laboratory assessment. Athletes composed 37.8% of the study participants. During the extended 10-year follow-up, 15 (17%) of the participants had self-limited syncopal episodes, but none had experienced life-threatening events. According to Holter recordings, none of the participants had heart rate <30 beats per minute or a pause longer than 3 seconds. Compared with 67 age- and sex-matched controls, the variables of heart rate based on the spectral and time domain analysis of the participants with sinus bradycardia were all significantly higher, indicating higher parasympathetic activity. The results of mutation analysis were negative in the HCN4 gene in all of our participants. CONCLUSIONS The long-term outcomes of the children and adolescents with sinus bradycardia identified using school electrocardiographic survey are favorable. Parasympathetic hyperactivity, instead of HCN4 gene mutation, is responsible for the occurrence of sinus bradycardia.
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Affiliation(s)
- Shuenn-Nan Chiu
- Department of Pediatrics, National Taiwan University Hospital and Medical College, National Taiwan University, Taipei, Taiwan
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Unaltered R-R interval variability and bradycardia in cyclists as compared with non-athletes. Clin Auton Res 2013; 23:141-8. [PMID: 23657540 DOI: 10.1007/s10286-013-0196-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 04/24/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE To test whether elite mountain bikers display a cardiac autonomic modulation pattern that is distinctive from that of active non-athletes. BACKGROUND The relationship between autonomic adaptation and bradycardia during physical exercise, including high-performance sports such as the mountain biking, remains to be elucidated. METHODS Twelve elite mountain bikers and 11 matched non-athletes controls were evaluated for time- and frequency-domain heart rate variability based on a 5-min ECG R-R intervals series obtained in both the supine and the orthostatic positions. Oxygen uptake and pulse rate were obtained at ventilatory thresholds and peak effort during an incremental cardiopulmonary exercise test. Significance of differences between medians (25th, 75th percentiles) from the two groups was evaluated by the Mann-Whitney test at p ≤ 0.05. RESULTS Athletes had lower heart rate [50 (47, 59) versus 63 (60, 69) bpm; p = 0.0004] and higher cardiopulmonary performance than controls [70.9 (64.6, 74.4) versus 47.7 (41.0, 51.9) mL (kg min)(-1); p = 0.01]. No statistical difference was found in heart rate variability in the group of athletes (p = 0.17-0.97), except for trend toward having lower coefficient of variation and low-frequency absolute power indices both in supine position (p = 0.06). CONCLUSIONS Bradycardia and higher oxygen uptake were found in association with unaltered cardiac autonomic modulation in elite mountain bikers athletes in supine and orthostatic positions, compared to active non-athletes. This bradycardia was not dependent on distinctive resting autonomic modulation. Intrinsic adaptation of sinus node and/or a peculiar state of autonomic adaptation to this exercise can be possible mechanisms.
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Betros C, McKeever N, Manso Filho H, Malinowski K, McKeever K. Effect of training on intrinsic and resting heart rate and plasma volume in young and old horses. COMPARATIVE EXERCISE PHYSIOLOGY 2013. [DOI: 10.3920/cep12020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The chronic bradycardia seen in several species after intense exercise training may be due to autonomic mechanisms, non-autonomic mechanisms, such as increased pre-load, or a combination of the two. Thirteen, healthy, unfit Standardbred mares were split into two groups: young (age 12±1 yr; mean ± standard error, n=8) and old (age 22±1 yr, n=5) to test the hypothesis that there would be age and training related differences in resting heart rate (RHR), intrinsic heart rate (IHR), maximal heart rate (HRmax) and plasma volume (PV). Mares were trained 3 d/wk at 60% HRmax for 20 min and gradually increased to exercising 5 d/wk at 70% HRmax for 30 min and RHR, IHR, HRmax, and PV were measured prior to and after the 8 wk training period. There were no age related differences (P≯0.05) between young and old mares before (41±2 vs. 42±2 beats per minute (bpm); 86±5 vs. 80±4 bpm) or after training (35±1 vs. 34±1 bpm; 81±6 vs. 78±2 bpm) for RHR and IHR respectively. RHR was decreased (P<0.05) following training in both the young (41±2 vs. 35±1 bpm) and old mares (42±2 vs. 34±2 bpm). Training decreased IHR (P<0.05) in the young mares (86±5 vs. 81±6 bpm), but not (P≯0.05) the old mares (80±4 vs. 78±2 bpm). The young horses had a higher HRmax than the old horses (P<0.05) both before (216±5 vs. 200±4 bpm) and after training (218±3 vs. 197±5 bpm). Maximal heart rate was not altered after training (P≯0.05) in either young (216±5 vs. 218±3 bpm) or old (200±4 vs. 197±5 bpm) mares. The PV of the young mares was 15% higher before training and 32% higher after training when compared to the old mares (P<0.05). Training caused an increase in PV in young mares (+9%; P<0.05), but did not alter PV in old mares (-5%; P≯0.05). Training improved RHR in the young but not the old horses. The decrease in measured parameters in the young horses appears to be related to enhanced pre-load associated with a training-induced hypervolemia as well as changes in autonomic function.
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Affiliation(s)
- C.L. Betros
- Equine Science Center, Department of Animal Sciences, Rutgers the State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901-8525, USA
| | - N.M. McKeever
- Equine Science Center, Department of Animal Sciences, Rutgers the State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901-8525, USA
| | - H.C. Manso Filho
- Equine Science Center, Department of Animal Sciences, Rutgers the State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901-8525, USA
| | - K. Malinowski
- Equine Science Center, Department of Animal Sciences, Rutgers the State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901-8525, USA
| | - K.H. McKeever
- Equine Science Center, Department of Animal Sciences, Rutgers the State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901-8525, USA
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Training-related modulations of the autonomic nervous system in endurance athletes: is female gender cardioprotective? Eur J Appl Physiol 2012; 113:631-40. [DOI: 10.1007/s00421-012-2474-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 08/01/2012] [Indexed: 10/27/2022]
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The training-induced changes on automatism, conduction and myocardial refractoriness are not mediated by parasympathetic postganglionic neurons activity. Eur J Appl Physiol 2011; 112:2185-93. [PMID: 21968799 DOI: 10.1007/s00421-011-2189-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 09/19/2011] [Indexed: 10/17/2022]
Abstract
The purpose of this study is to test the role that parasympathetic postganglionic neurons could play on the adaptive electrophysiological changes produced by physical training on intrinsic myocardial automatism, conduction and refractoriness. Trained rabbits were submitted to a physical training protocol on treadmill during 6 weeks. The electrophysiological study was performed in an isolated heart preparation. The investigated myocardial properties were: (a) sinus automatism, (b) atrioventricular and ventriculoatrial conduction, (c) atrial, conduction system and ventricular refractoriness. The parameters to study the refractoriness were obtained by means of extrastimulus test at four different pacing cycle lengths (10% shorter than spontaneous sinus cycle length, 250, 200 and 150 ms) and (d) mean dominant frequency (DF) of the induced ventricular fibrillation (VF), using a spectral method. The electrophysiological protocol was performed before and during continuous atropine administration (1 μM), in order to block cholinergic receptors. Cholinergic receptor blockade did not modify either the increase in sinus cycle length, atrioventricular conduction and refractoriness (left ventricular and atrioventricular conduction system functional refractory periods) or the decrease of DF of VF. These findings reveal that the myocardial electrophysiological modifications produced by physical training are not mediated by intrinsic cardiac parasympathetic activity.
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van Lien R, Goedhart A, Kupper N, Boomsma D, Willemsen G, de Geus EJ. Underestimation of cardiac vagal control in regular exercisers by 24-hour heart rate variability recordings. Int J Psychophysiol 2011; 81:169-76. [DOI: 10.1016/j.ijpsycho.2011.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 05/10/2011] [Accepted: 06/13/2011] [Indexed: 11/27/2022]
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McLachlan CS, Ocsan R, Spence I, Hambly B, Matthews S, Wang L, Jelinek HF. Increased total heart rate variability and enhanced cardiac vagal autonomic activity in healthy humans with sinus bradycardia. Proc (Bayl Univ Med Cent) 2011; 23:368-70. [PMID: 20944759 DOI: 10.1080/08998280.2010.11928655] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Sinus bradycardia can be defined as a sinus rhythm with a resting heart rate of 60 beats per minute or less. While it is assumed that increased autonomic parasympathetic activity is associated with sinus bradycardia, such an association has yet to be proven. The aims of this study were to compute a number of heart rate variability (HRV) parameters in healthy individuals with sinus bradycardia and determine whether there was a significant vagal component to sinus bradycardia. Forty-three healthy adults with normal sinus rhythm and 25 healthy adults with sinus bradycardia had an electrocardiogram recorded for 20 minutes, from which HRV indices were calculated. Results showed significant increases in SDNN (standard deviation of NN intervals) (P < 0.05), RMSDD (square root of the mean squared differences of successive NN intervals) (P < 0.05), and DFA32 (detrended fluctuation analysis) (P < 0.05) in bradycardic subjects compared with subjects with normal sinus rhythm. There were no significant differences in sympathetic frequency domain indices between the two groups. In conclusion, there were significant increases in total heart variability and increased parasympathetic drive in subjects with bradycardia. Clinically, bradycardia is likely to be cardioprotective in aging populations based upon these HRV findings.
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Affiliation(s)
- Craig S McLachlan
- Department of Physiology, National University of Singapore, Singapore (McLachlan); the Kolling Institute, the Sydney Medical School, the University of Sydney, Australia (McLachlan); the Departments of Pharmacology (Spence, Matthews) and Pathology (Ocsan, Hambly), the University of Sydney, Sydney, Australia; the School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, Australia (Wang); and the School of Community Health, Charles Sturt University, Albury, Australia (Jelinek)
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Pavlik G, Major Z, Varga-Pintér B, Jeserich M, Kneffel Z. The athlete’s heart Part I (Review). ACTA ACUST UNITED AC 2010; 97:337-53. [DOI: 10.1556/aphysiol.97.2010.4.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Sridhar B, Haleagrahara N, Bhat R, Kulur AB, Avabratha S, Adhikary P. Increase in the heart rate variability with deep breathing in diabetic patients after 12-month exercise training. TOHOKU J EXP MED 2010; 220:107-13. [PMID: 20139661 DOI: 10.1620/tjem.220.107] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Autonomic neuropathy in diabetes leads to impaired regulation of blood pressure and heart rate variability (HRV), which is due to a shift in cardiac autonomic balance towards sympathetic dominance. Lower HRV has been considered a predictor of cardiac mortality and morbidity. Deep breathing test is a simple method to measure HRV and it provides a sensitive measure of cardiac autonomic function. The effect of long-term physical activity on HRV in type-2 diabetes mellitus is inconclusive. We aimed to evaluate the effects of regular physical exercise on HRV with deep breathing in type 2 diabetes (n = 105). Thirty normotensive diabetic patients and 25 hypertensive diabetic patients underwent physical exercise program for 12 months, and the other 50 patients (22 normotensive and 28 hypertensive diabetic patients) were considered the non-exercised group. Electrocardiogram was recorded during deep breathing and HRV was measured. Regular exercise significantly increased HRV in diabetic patients with and without hypertension. The degree of the increase in HRV was greater in hypertensive diabetic patients (p < 0.01) than in normotensive diabetic patients (p < 0.05). After exercise, glycosylated hemoglobin levels were decreased in both groups of diabetic patients. Moreover, the hypertensive diabetic patients showed a decrease (p < 0.05) in blood pressure after regular exercise. Thus, regular exercise training increases HRV, suggesting that there is a shift in the cardiac sympathovagal balance in favor of parasympathetic dominance in diabetic patients. Long-term physical training may be an effective means to reverse the autonomic dysregulation seen in type 2 diabetes.
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Cornelissen VA, Goetschalckx K, Verheyden B, Aubert AE, Arnout J, Persu A, Rademakers F, Fagard RH. Effect of endurance training on blood pressure regulation, biomarkers and the heart in subjects at a higher age. Scand J Med Sci Sports 2010; 21:526-34. [PMID: 20459467 DOI: 10.1111/j.1600-0838.2010.01094.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We reported previously that two otherwise identical training programs at lower (LI) and higher intensity (HI) similarly reduced resting systolic blood pressure (BP) by approximately 4-6 mmHg. Here, we determined the effects of both programs on BP-regulating mechanisms, on biomarkers of systemic inflammation and prothrombotic state and on the heart. In this cross-over study (3 × 10 weeks), healthy participants exercised three times 1 h/week at, respectively, 33% and 66% of the heart rate (HR) reserve, in a random order, with a sedentary period in between. Measurements, performed at baseline and at the end of each period, involved blood sampling, HR variability, systolic BP variability (SBPV) and cardiac magnetic resonance imaging. Thirty-nine participants (18 men; mean age 59 years) completed the study. Responses were not different between both programs (P>0.05). Pooled data from LI and HI showed a reduction in HR (-4.3 ± 8.1%) and an increase in stroke volume (+11 ± 23.1%). No significant effect was seen on SBPV, plasma renin activity, basal nitric oxide and left ventricular mass. Our results suggest that the BP reduction observed appears to be due to a decrease in systemic vascular resistance; training intensity does not significantly affect the results on mechanisms, biomarkers and the heart.
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Affiliation(s)
- V A Cornelissen
- Division of Hypertension and Cardiovascular Rehabilitation, Department of Cardiovascular, Diseases, Faculty of Medicine, University of Leuven, KU Leuven, Leuven, Belgium.
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Cornelissen VA, Verheyden B, Aubert AE, Fagard RH. Effects of aerobic training intensity on resting, exercise and post-exercise blood pressure, heart rate and heart-rate variability. J Hum Hypertens 2009; 24:175-82. [DOI: 10.1038/jhh.2009.51] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Platisa MM, Mazic S, Nestorovic Z, Gal V. Complexity of heartbeat interval series in young healthy trained and untrained men. Physiol Meas 2008; 29:439-50. [PMID: 18354245 DOI: 10.1088/0967-3334/29/4/002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The origin of heart rate variability (HRV) is largely in parasympathetic activity. The direct influence of sympathetic activity and other control mechanisms, especially at an increased HR, is not well understood. The objectives of the study were to investigate the influence of increasing HR on the properties of heartbeat interval (RR) series in young healthy subjects. ECG was recorded in 9 trained and 11 untrained young men during supine rest, standing, incremental running exercise and relaxation. During exercise, a breath-to-breath gas exchange was monitored. The RR time series analysis included the spectral analysis, detrended fluctuations analysis method and sample entropy (SampEn) calculation. During exercise, spectral powers were reduced dramatically in both groups. The dependence of short-term scaling exponent (alpha(1)) on the RR included a characteristic maximum, while SampEn for the same value of the RR had a minimum. The value of HR corresponding to the maximum of alpha(1) and minimum of SampEn (IHR) corresponded to the intrinsic HR obtained by an autonomic blockade. In trained subjects, the curves alpha(1) versus RR and SampEn versus RR were moved toward larger RR, compared with control. For HR values higher than IHR, alpha(1) decreased and SampEn increased. These results reveal that the complexity of the heart rhythm above intrinsic HR decreases with an increase in HR. We suggest that at the highest HR intrinsic heart control is reflected in the heart rhythm. We point out the possibility of developing a new non-invasive method for the determination of intrinsic HR from the curve alpha(1) versus RR.
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Affiliation(s)
- Mirjana M Platisa
- Institute of Biophysics, Faculty of Medicine, University of Belgrade, Visegradska 26, 11000 Belgrade, Serbia.
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18
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Lee K, Picard G, Beske SD, Hwang GS, Taylor JA. Effects of fitness and age on the response to vagotonic atropine. Auton Neurosci 2008; 139:60-7. [PMID: 18321791 DOI: 10.1016/j.autneu.2008.01.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 12/15/2007] [Accepted: 01/30/2008] [Indexed: 11/29/2022]
Abstract
Previous work indicates compromised cardiac vagal control plays a prominent role in reducing arterial baroreflex gain with age, however older fit individuals display cardiovagal baroreflex responses similar to young individuals. The purpose of this study was to test the hypothesis that chronic aerobic exercise mitigates against age-related declines in cardiac parasympathetic receptor function. In forty-four young and old (fit and unfit) individuals, we used the parasympathomimetic responses to low doses of atropine to probe cardiac cholinergic receptor responses. Data were collected before and after eight doses of atropine sulfate from 0.4 to 7.2 microg/kg. Chronotropic responses were assessed from average RR intervals and heart rate variabilities were derived in time and frequency domains. All subjects exhibited bradycardia with at least one dose of atropine and peak bradycardia occurred at a similar dose in each group. However, changes in heart rate variability did not consistently track the chronotropic responses within subjects (r-square from 0.90 down to 0). As expected, basal RR interval was longer in the fit groups and was unaffected by age. However, the degree of RR interval lengthening with parasympathomimetic atropine was unaffected by physical fitness and was significantly less in all older subjects. These data indicate there are certain prepotent age-related declines in the cardiac parasympathetic system that cannot be prevented by regular physical activity.
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Affiliation(s)
- Kichang Lee
- Cardiovascular Research Laboratory, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA 02114, USA
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19
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Sandercock G. Normative values, reliability and sample size estimates in heart rate variability. Clin Sci (Lond) 2007; 113:129-30. [PMID: 17451377 DOI: 10.1042/cs20070137] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
HRV (heart rate variability) is a non-invasive maker of cardiac autonomic modulation utilized in many hundreds of scientific studies each year. The reliability of heart rate variability has been frequently investigated yet remains poorly quantified. Assessing the reliability of a measure that assesses dynamic physiological processes and shows large between- and within-subject variation is a complex task. In this issue of Clinical Science, Pinna and co-workers provide excellent insight into the test-retest reliability of commonly used HRV indices and put the values obtained into context by comparing them with levels of between-subject variation and by producing sample size estimates.
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Affiliation(s)
- Gavin Sandercock
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, UK.
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Chattipakorn N, Incharoen T, Kanlop N, Chattipakorn S. Heart rate variability in myocardial infarction and heart failure. Int J Cardiol 2007; 120:289-96. [PMID: 17349699 DOI: 10.1016/j.ijcard.2006.11.221] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 11/20/2006] [Accepted: 11/21/2006] [Indexed: 12/11/2022]
Abstract
The need to refine the identification of patients who might benefit from implantation of an implantable cardioverter defibrillator has been risen by the results of many clinical trials on ICD therapy. Traditional parameters such as left ventricular ejection fraction and the presence of non-sustained ventricular tachycardia were not strong enough to achieve this goal with reasonable cost-effectiveness. Heart rate variability (HRV) is one of the most popular parameters used to assess the autonomic tone. HRV has been reported as a strong predictor of cardiovascular mortality. Currently, three different categories of methods in HRV analysis are being used; the time domain, frequency domain, and non-linear dynamic analysis. Both time domain and frequency domain analyses of HRV have been investigated extensively regarding their use as a prognostic marker for cardiovascular mortality. The non-linear dynamic analysis is the latest tool that has shown to have an even higher predictive value than any of the traditional parameters. However, standardized and supporting evidence on this new technique is still lacking. In this article, the current role of HRV in the prediction of cardiovascular mortality in myocardial infarction and heart failure patients has been reviewed.
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Affiliation(s)
- Nipon Chattipakorn
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
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21
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Grossman P, Taylor EW. Toward understanding respiratory sinus arrhythmia: relations to cardiac vagal tone, evolution and biobehavioral functions. Biol Psychol 2006; 74:263-85. [PMID: 17081672 DOI: 10.1016/j.biopsycho.2005.11.014] [Citation(s) in RCA: 670] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2005] [Indexed: 11/16/2022]
Abstract
Respiratory sinus arrhythmia (RSA, or high-frequency heart-rate variability) is frequently employed as an index of cardiac vagal tone or even believed to be a direct measure of vagal tone. However, there are many significant caveats regarding vagal tone interpretation: 1. Respiratory parameters can confound relations between RSA and cardiac vagal tone.2. Although intraindividual relations between RSA and cardiac vagal control are often strong, interindividual associations may be modest.3. RSA measurement is profoundly influenced by concurrent levels of momentary physical activity, which can bias estimation of individual differences in vagal tone.4. RSA magnitude is affected by beta-adrenergic tone.5. RSA and cardiac vagal tone can dissociate under certain circumstances.6. The polyvagal theory contains evolution-based speculations that relate RSA, vagal tone and behavioral phenomena. We present evidence that the polyvagal theory does not accurately depict evolution of vagal control of heart-rate variability, and that it ignores the phenomenon of cardiac aliasing and disregards the evolution of a functional role for vagal control of the heart, from cardiorespiratory synchrony in fish to RSA in mammals. Unawareness of these issues can lead to misinterpretation of cardiovascular autonomic mechanisms. On the other hand, RSA has been shown to often provide a reasonable reflection of cardiac vagal tone when the above-mentioned complexities are considered. Finally, a recent hypothesis is expanded upon, in which RSA plays a primary role in regulation of energy exchange by means of synchronizing respiratory and cardiovascular processes during metabolic and behavioral change.
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Affiliation(s)
- Paul Grossman
- Department of Psychosomatic and Internal Medicine, Psychophysiology Research Laboratory, University of Basel Hospital, Hebelstrasse 2, CH-4031 Basel, Switzerland.
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Melo RC, Santos MDB, Silva E, Quitério RJ, Moreno MA, Reis MS, Verzola IA, Oliveira L, Martins LEB, Gallo-Junior L, Catai AM. Effects of age and physical activity on the autonomic control of heart rate in healthy men. Braz J Med Biol Res 2005; 38:1331-8. [PMID: 16138216 DOI: 10.1590/s0100-879x2005000900007] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
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 indices: expiration/inspiration ratio (E/I) and inspiration-expiration difference (deltaIE). The active groups had lower HR and higher RMSSD index than the sedentary groups (life-style condition: sedentary vs active, P < 0.05). The older groups showed lower HFnu, higher LFnu and higher LF/HF ratio than the young groups (aging effect: young vs older, P < 0.05). The OS group had a lower E/I ratio (1.16) and deltaIE (9.7 bpm) than the other groups studied (YS: 1.38, 22.4 bpm; YA: 1.40, 21.3 bpm; OA: 1.38, 18.5 bpm). The interaction between aging and life-style effects had a P < 0.05. These results suggest that aging reduces HR variability. However, regular physical activity positively affects vagal activity on the heart and consequently attenuates the effects of aging in the autonomic control of HR.
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Affiliation(s)
- R C Melo
- Departamento de Fisioterapia, Universidade Federal de São Carlos, São Carlos, SP, Brazil
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Abstract
Mechanisms responsible for atrial fibrillation are not completely understood but the autonomic nervous system is a potentially potent modulator of the initiation, maintenance, termination and ventricular rate determination of atrial fibrillation. Complex interactions exist between the parasympathetic and sympathetic nervous systems on the central, ganglionic, peripheral, tissue, cellular and subcellular levels that could be responsible for alterations in conduction and refractoriness properties of the heart as well as the presence and type of triggered activity, all of which could contribute to atrial fibrillation. These dynamic inter-relationships may also be altered dependent upon other neurohumoral modulators and cardiac mechanical effects from ventricular dysfunction and congestive heart failure. The clinical implications regarding the effects of the autonomic nervous system in atrial fibrillation are widespread. The effects of modulating ganglionic input into the atria may alter the presence or absence of atrial fibrillation as has been highlighted from ablation investigations. This article reviews what is known regarding the inter-relationships between the autonomic nervous system and atrial fibrillation and provides state of the art information at all levels of autonomic interactions.
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Affiliation(s)
- Brian Olshansky
- Department of Internal Medicine, University of Iowa Hospitals, Iowa City, IA 52242, USA.
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Evangelista FS, Martuchi SED, Negrão CE, Brum PC. Loss of resting bradycardia with detraining is associated with intrinsic heart rate changes. Braz J Med Biol Res 2005; 38:1141-6. [PMID: 16007286 DOI: 10.1590/s0100-879x2005000700018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The mechanisms underlying the loss of resting bradycardia with detraining were studied in rats. The relative contribution of autonomic and non-autonomic mechanisms was studied in 26 male Wistar rats (180-220 g) randomly assigned to four groups: sedentary (S, N = 6), trained (T, N = 8), detrained for 1 week (D1, N = 6), and detrained for 2 weeks (D2, N = 6). T, D1 and D2 were treadmill trained 5 days/week for 60 min with a gradual increase towards 50% peak VO2. After the last training session, D1 and D2 were detrained for 1 and 2 weeks, respectively. The effect of the autonomic nervous system in causing training-induced resting bradycardia and in restoring heart rate (HR) to pre-exercise training level (PET) with detraining was examined indirectly after cardiac muscarinic and adrenergic receptor blockade. T rats significantly increased peak VO2 by 15 or 23.5% when compared to PET and S rats, respectively. Detraining reduced peak VO2 in both D1 and D2 rats by 22% compared to T rats, indicating loss of aerobic capacity. Resting HR was significantly lower in T and D1 rats than in S rats (313 +/- 6.67 and 321 +/- 6.01 vs 342 +/- 12.2 bpm) and was associated with a significantly decreased intrinsic HR (368 +/- 6.1 and 362 +/- 7.3 vs 390 +/- 8 bpm). Two weeks of detraining reversed the resting HR near PET (335 +/- 6.01 bpm) due to an increased intrinsic HR in D2 rats compared with T and D1 rats (376 +/- 8.8 bpm). The present study provides the first evidence of intrinsic HR-mediated loss of resting bradycardia with detraining in rats.
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Affiliation(s)
- F S Evangelista
- Departamento de Biodinâmica do Movimento do Corpo Humano, Escola de Educação Física e Esporte, Universidade de São Paulo, SP, Brasil
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