Journal ArticleDOI
Non-autonomic component in bradycardia of endurance trained men at rest and during exercise.
TLDR
Evidence is provided for a non-autonomic component in the bradycardia of well-trained men which may be responsible for a parallel downward shift in the relationship between HR and percentage of VO2 max, which might be explained by the cardiac enlargement.Abstract:
Autonomic nervous alterations have generally been held responsible for the bradycardia of the endurance athlete. In order to determine whether there is also a non-autonomic component in the bradycardia of long-term training, we compared the intrinsic heart rate (HR) of highly trained bicyclists (heart volume: 995 +/- 155 ml) with that of untrained men (heart volume: 805 +/- 195 ml) at rest and during bicycle ergometer exercise at 50, 75 and 100% of maximal oxygen uptake (VO2 max.) Intrinsic HR was achieved by combined vagal and beta-adrenergic blockade with atropine and propranolol or metoprolol (cardioselective) injected intravenously. Intrinsic HR was significantly lower in trained (T) than in untrained (UT) at rest and at all levels of exercise. The chronotropic reserve from resting HR to maximal HR was identical in the two groups. Nearly identical intrinsic HRs were achieved with atropine and either beta-adrenergic antagonist. HR differences between T and UT were very similar in magnitude--approximately 13 beats/min--at rest and during exercise at a given percentage of VO2 max, with and without autonomic blockade. Evidence is thus provided for a non-autonomic component in the bradycardia of well-trained men which may be responsible for a parallel downward shift in the relationship between HR and percentage of VO2 max. The lower intrinsic HR in well-trained men might be explained by, i.a. the cardiac enlargement.read more
Citations
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Journal ArticleDOI
Heart rate monitoring: applications and limitations.
Juul Achten,Asker E. Jeukendrup +1 more
TL;DR: There appears to be a small day-to-day variability in HR and a steady increase during exercise has been observed in most studies, and the effects of overreaching on submaximal HR are controversial, with some studies showing decreased rates and others no difference.
Journal ArticleDOI
Cardiovascular Adaptations to Physical Training
J Scheuer,Charles M. Tipton +1 more
TL;DR: The cardiovascular adaptations that occur during exercise in experimental animals and in man and how they contribute to the trained state are reviewed and the mechanisms underlying these adaptations are discussed.
Journal ArticleDOI
Cardiovascular Adaptations to Physical Training
C. G. Blomqvist,Bengt Saltin +1 more
TL;DR: In this paper, the authors reviewed the interaction between training-induced adaptations affecting the heart, including structural, meta-bolic, and regulatory, and concluded that functional capacity of the cardiovascular system is the principal limiting factor.
Journal ArticleDOI
Heart rate variability, trait anxiety, and perceived stress among physically fit men and women
Rod K. Dishman,Yoshio Nakamura,Melissa E. Garcia,Ray W. Thompson,Andrea L. Dunn,Steven N. Blair +5 more
TL;DR: It is concluded that vagal modulation of heart period appears to be sensitive to the recent experience of persistent emotional stress, regardless of a person's level of physical fitness and disposition toward experiencing anxiety.
Journal ArticleDOI
The athletic heart syndrome.
TL;DR: The large heart of athletes may be due to the prolonged use of their muscles, but no man becomes a great runner or oarsman who has not naturally a capable if not a large heart.
References
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Journal ArticleDOI
Cardiovascular Adaptations to Physical Training
J Scheuer,Charles M. Tipton +1 more
TL;DR: The cardiovascular adaptations that occur during exercise in experimental animals and in man and how they contribute to the trained state are reviewed and the mechanisms underlying these adaptations are discussed.
Journal ArticleDOI
The normal range and determinants of the intrinsic heart rate in man.
Anthony D. Jose,D. Collison +1 more
TL;DR: Normal standards for the intrinsic heart rate (IHR) were measured in 432 healthy adult subjects aged 16 to 70 years and in different subjects, age was the only important determinant.
Journal ArticleDOI
A Method for the Determination of the Heart Size by Teleroentgenography (A Heart Volume index)
TL;DR: The roentgenological examination of the heart developed in connection with clinical percussion was substituted by percussion on the anterior wall of the thorax were substituted bv the cardiac silhouette, shown on a post.