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标题：The Effect of Aerobic Training and Cardiac Autonomic Regulation in Young Adults
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作者：Richard P. Sloan ; Peter A. Shapiro ; Ronald E. DeMeersman 等
期刊名称：American journal of public health
印刷版ISSN：0090-0036
出版年度：2009
卷号：99
期号：5
页码：921-928
DOI：10.2105/AJPH.2007.133165
语种：English
出版社：American Public Health Association
摘要：Objectives. We tested the effect of aerobic exercise on autonomic regulation of the heart in healthy young adults. Methods. Healthy, sedentary young adults (n = 149; age = 30.4 ± 7.53 years) were randomized to receive 12 weeks of either aerobic conditioning or strength training. Primary outcomes were heart rate and RR interval variability (RRV) measured before and after training and after 4 weeks of sedentary deconditioning. RRV, a noninvasive index of cardiac autonomic regulation, reflects variability in the intervals between consecutive R waves of the electrocardiogram. Results. Aerobic conditioning but not strength training led to a significant increase in aerobic capacity (3.11 mL/kg/min), a decrease in heart rate (−3.49 beats per minute), and an increase in high-frequency RRV (0.25 natural log msec²), each of which returned to pretraining levels after deconditioning. Significant 3-way interactions, however, revealed autonomic effects only in men. Conclusions. In sedentary, healthy young adults, aerobic conditioning but not strength training enhances autonomic control of the heart, but post hoc analyses suggested that gender plays a significant role in this exercise-related cardioprotection. The public health benefits of physical exercise, especially for cardioprotection, are widely accepted, and consensus panels consistently have recommended exercise across the age spectrum as a central activity of a healthy life.^{1 – 3} Among the many biological mechanisms proposed to account for this risk-reducing effect is autonomic nervous system regulation of the heart. The role of the autonomic nervous system in cardioprotection is well established. Autonomic regulation of the heart may be measured noninvasively as variation in the time series of intervals between consecutive R waves (the representation of depolarization of the ventricles) in the electrocardiogram. RR interval variability (RRV) at high frequencies (0.15–0.50 Hz) reflects cardiac parasympathetic modulation, and variability at lower frequencies (0.04–0.15 Hz) reflects both sympathetic and parasympathetic influences in the heart. RRV is a strong prognostic indicator for the development of cardiovascular disease and death in community-dwelling nonclinical populations^{4 , 5} and for progression of heart disease in patients,⁶ suggesting a role for the autonomic nervous system in the pathophysiology of coronary artery disease. Low levels of RRV also predict death after acute myocardial infarction^{7 , 8} and heart failure,⁹ consistent with the hypothesis that increased cardiac parasympathetic nervous system regulation protects against arrhythmic death.¹⁰ Most studies report that aerobic conditioning enhances autonomic control of the heart, as indicated by training-induced reductions in heart rate or increases in RRV, but the evidence is only partially consistent with training-induced autonomic benefits. Many studies report no effect of training or no difference between trained and sedentary participants in heart rate^{11 – 13} or RRV.^{14 – 17} Cross-sectional studies often contrast highly trained athletes with sedentary controls, raising the possibility of self-selection biases. Longitudinal studies of training often have only a small number of participants^{15 , 18} or lack a control group,¹⁹ and many include men only.^{18 , 20 – 24} To address these concerns, we contrasted the cardiac autonomic effect of aerobic conditioning with that of strength training in a large sample of healthy young men and women. We hypothesized that cardiac autonomic regulation would be improved by aerobic conditioning but not strength training.