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Douglas R. Seals, Kevin D. Monahan, Christopher Bell, Hirofumi Tanaka and Pamela P. Jones

Tonic vagal modulation of cardiac period (R-R interval) decreases with advancing age, but is greater in middle-aged and older adults who habitually perform aerobic exercise compared with their sedentary peers. Cardiovagal baroreflex sensitivity also declines markedly with age in sedentary adults but only 50% as much in regularly exercising adults. In previously sedentary middle-aged and older adults, a 3-month program of moderate aerobic exercise increases cardiovagal baroreflex sensitivity by 25%. Tonic (basal) sympathetic nervous system (SNS) activity increases with advancing age in both sedentary and habitually exercising adults. Despite this, SNS b-adrenergic support of energy metabolism (resting metabolic rate-RMR) declines with age in sedentary individuals. However, SNS b-adrenergic support of RMR is maintained with age inenduranceexercise-trainedadultsandthereforeismuchgreaterinmiddle-aged and older individuals who exercise regularly compared with their sedentary peers. Thus, regular aerobic (endurance) exercise modulates selective age associated impairments in autonomic nervous system-physiological function.

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Hermann-J. Engels, John C. Wirth, Sueda Celik and Jodee L. Dorsey

This study assessed the influence of caffeine on metabolic and cardiovascular functions during sustained, light intensity cycling and at rest. Eight healthy, recreationally active adults participated in four randomly assigned, double-blind experimental trials of 60 min upright seated cycle exercise (30% VO2max) or equivalent rest with caffeine (5 mg ⋅ kg−1) or placebo consumed 60 min prior to data collection. Gas exchange was measured by open-circuit spirom-etry indirect calorimetry. Global blood flow was evaluated by thoracic impedance cardiography and arterial blood pressure by auscultation. A repeated measures ANOVA indicated that pretrial caffeine increased oxygen uptake and energy expenditure rate (p < 0.05) but did not change respiratory exchange ratio. Systolic, diastolic, and mean arterial blood pressure were elevated following caffeine intake (p < 0.05). Cardiac output, heart rate, stroke volume, and systemic vascular resistance were not significantly different between caffeine and placebo sessions. For each of the metabolic and hemodynamic variables examined, the effects of caffeine were similar during constant-load, light intensity cycling and at rest. These data illustrate that caffeine's mild thermogenic influence can be mediated without a major shift in substrate oxidation mixture. Caffeine at this dosage level alters cardiovascular dynamics by augmenting arterial blood pressure.

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Petter Fagerberg

on hormonal levels, psychology, muscle mass, and the cardiovascular system. A prolonged EA of ∼20–25 kcal/kg FFM seems to be pathological for males, especially when approaching the lower limits of BF. These levels of EA (20–25 kcal/kg FFM) are lower than the treshold level (EA < 30 kcal/kg FFM

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Pablo Jodra, Raúl Domínguez, Antonio J. Sánchez-Oliver, Pablo Veiga-Herreros and Stephen J. Bailey

had completed the Wingate test, they were presented with the 6 to 20 RPE scale. Participants were then asked to indicate the RPE related to their leg muscles (RPE muscular ), cardiovascular system (RPE cardio ), and general overall RPE (RPE general ). Statistical Analysis All data were initially

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Günther Lüschen, William Cockerham and Gerhard Kunz

The review of existing research shows the health impacts of sport mainly on the cardiovascular system. Other causal relations are less firm, and results for the skeleton and accidents appear to be negative. Results of the American-German Health Study of 1985 confirm such results and indicate that sports’ interdependence with health culture is stronger than a supposedly causal impact on indicators of health status.

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Fuzhong Li, K. John Fisher, Peter Harmer and Machiko Shirai

Low-impact exercise that appeals to elderly adults and can be done almost anywhere provides both societal and individual benefits. One such program is Tai Chi, a traditional Chinese dancelike conditioning exercise. The article presents an easily adopted and adapted 8-form Tai Chi program (Easy Tai Chi) designed for older adults or individuals with mobility challenges or physical impairments. Derived from a simplified 24-form Yang-style Tai Chi, it stresses postural control and body-limb rotational movements. Easy Tai Chi can be performed either standing or sitting, depending on the physical and functional limitations of participants. Preliminary data indicate a number of health benefits of Easy Tai Chi compared with a traditional exercise program. Although subject to further empirical evaluation, Easy Tai Chi can be applied in research settings to investigate prevention or amelioration of hypokinetic diseases and in clinical settings to treat physically frail seniors or others with functional impairments of the musculoskeletal or cardiovascular system.

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Pamela Hodges Kulinna, Jeffrey Martin, Qin Lai, Amy Kliber and Brett Reed

The purpose of this study was to determine how physical education students’ cardiovascular responses as determined by mean heart rate, standard deviation of heart rate, and percentage of time in target heart rate zone varied according to student characteristics. Participants were 505 students in Grades 3 through 12. The Polar Accurex Plus heart rate telemetry system was used to measure the physiological load on the cardiovascular system. Three-way ANOVA results suggested that heart rate patterns in physical education varied according to gender, grade, and activity. For example, secondary school girls were more active in individual activities while secondary school boys were more active in team sport activities. Elementary students were the most active group and had the most variability in their heart rate patterns.

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Christian C. Evans, Lisa Schwarz and Minal Masihi

Context:

Sudden cardiac death in athletes may be preventable if healthcare providers perform a thorough screening of the cardiovascular system during routine athlete evaluations.

Objective:

Determine the adequacy of routine screening of athletes for heart disease by athletic trainers (ATs) and physical therapists (PTs).

Design, Participants, Setting, and Methods:

National Athletic Trainers Association and Sports Physical Therapy Section members were surveyed using a stratified sampling technique via e-mail and postal mail.

Results:

ATs performed significantly higher than PTs on the composite screening score (CSS; mean of 13 items) as well as on 9 of 13 individual items. Logistic regression analysis revealed that “involvement in preparticipation screenings for sports (PPSS)” was most closely related to CSS (P < .01) and controlling for this factor in the ANOVA eliminated differences between the professions.

Conclusions:

Clinicians working with athletes who are not involved in PPSS may not adequately screen these patients for heart disease.

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Vinícius Y.B. Suetake, Emerson Franchini, Bruna T.C. Saraiva, Anne K.F. da Silva, Aline F.B. Bernardo, Rayane L. Gomes, Luiz Carlos M. Vanderlei and Diego G.D. Christofaro

Purpose: The aim of the study was to evaluate the cardiac autonomic modulation after 9 months of martial arts practice in healthy children and adolescents. Method: The study included 59 children and adolescents who were divided into 3 groups: judo, Muay Thai, and control. Heart rate variability was measured by a heart rate monitor, model Polar RS800CX. The intervention occurred twice a week on nonconsecutive days, lasting 60 minutes each session. A 1-way analysis of variance was used to compare participants at baseline. The comparisons between groups at baseline and after the intervention were carried out by a 2-way analysis of variance for repeated measures. Results : After 9 months of intervention, significant increases were observed for root mean square successive differences, with higher values post compared with baseline (19.5%; P = .04). For SD1, an interaction effect was observed, with increased posttraining values compared with baseline (24.1%; P = .04) for the judo group. Qualitative analysis of the Poincaré plot showed greater dispersion of RR intervals, mainly beat to beat, after the judo intervention compared with the baseline. The Muay Thai and control groups presented no improvement. Conclusion : After 9 months of intervention, there were increases in cardiac autonomic modulation of children and adolescents participating in judo training. The practice of martial arts, such as judo, can be encouraged from an early age to improve cardiovascular system functioning, possibly providing protection against cardiovascular problems.

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Santiago Lopez, Jan G. Bourgois, Enrico Tam, Paolo Bruseghini and Carlo Capelli

Purpose:

To explore the cardiovascular and metabolic responses of 9 Optimist sailors (12.7 ± 0.8 y, 153 ± 9 cm, 41 ± 6 kg, sailing career 6.2 ± 1 y, peak oxygen uptake [V̇O2peak] 50.5 ± 4.5 mL · min−1 · kg−1) during on-water upwind sailing with various wind intensities (W).

Methods:

In a laboratory session, peak V̇O2, beat-by-beat cardiac output (Q̇), mean arterial blood pressure (MAP), and heart rate (f H) were measured using a progressive cycle ramp protocol. Steady-state V̇O2, Q̇, MAP, and f H at 4 submaximal workloads were also determined. During 2 on-water upwind sailing tests (constant course and with tacks), W, Q̇, MAP, and f H were measured for 15 min. On-water V̇O2 was estimated on the basis of steady-state f H measured on water and of the individual ΔV̇O2f H relationship obtained in the laboratory.

Results:

V̇O2, f H, and Q̇ expressed as percentage of the corresponding peak values were linearly related with W; exercise intensity during on-water sailing corresponded to 46–48% of V̇O2peak. MAP and total vascular peripheral resistance (TPR = MAP/Q̇) were larger (P < .005) during on-water tests (+39% and +50%, respectively) than during cycling, and they were correlated with W. These responses were responsible for larger values of the double (DP) and triple (TP) products of the heart during sailing than during cycling (P < .005) (+37% and +32%, respectively).

Conclusions:

These data indicate that the cardiovascular system was particularly stressed during upwind sailing even though the exercise intensity of this activity was not particularly high.