Document Detail


Differences in autonomic modulation of heart rate during arm and leg exercise.
MedLine Citation:
PMID:  10451789     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Heart rate (HR) is higher during dynamic arm exercise than during leg exercise at equal oxygen consumption levels, but the physiological background for this difference is not completely understood. The vagally mediated beat-to-beat R-R interval fluctuation decreases until the level of approximately 50% of maximal oxygen consumption during an incremental bicycle exercise, but the vagal responses to arm exercise are not well known. Changes in autonomic modulation of HR were compared during arm and leg exercise by measuring beat-to-beat R-R interval variability from a Poincaré plot normalized for the average R-R interval (SD1n), a measure of vagal activity, in 14 healthy male subjects (age 20 +/- 4 years) who performed graded bicycle and arm cranking tests until exhaustion. Seven of the subjects also performed the dynamic arm and leg tests after beta-adrenergic blockade (propranolol 0.2 mg kg-1 i.v.). More rapid reduction occurred in SD1n during the low-intensity level of dynamic arm exercise than during dynamic leg exercise without beta-blockade (e.g. 11 +/- 6 vs. 20 +/- 10 at the oxygen consumption level of 1.2 l min-1; P < 0.001) and with beta-blockade (e.g. 13 +/- 4 vs. 25 +/- 10 at the level of 1.0 l min-1; P < 0.05), and the mean HR was significantly higher during submaximal arm work than during leg work in both cases (e.g. during beta-blockade 81 +/- 12 vs. 74 +/- 6 beats min-1 at the level of 1.0 l min-1; P < 0.05). These data show that dynamic arm exercise results in more rapid withdrawal of vagal outflow than dynamic leg exercise.
Authors:
M P Tulppo; T H Mäkikallio; R T Laukkanen; H V Huikuri
Related Documents :
7556119 - Are oxygen uptake kinetics at the onset of exercise speeded up by local metabolic statu...
12582149 - Skiing across the greenland icecap: divergent effects on limb muscle adaptations and su...
12475469 - Isometric arm counter-pressure maneuvers to abort impending vasovagal syncope.
7225749 - The relationship between the number of capillaries in the skin of the venous ulcer-bear...
4640949 - Free fatty acid metabolism of leg muscles during exercise in patients with obliterative...
6728649 - Reflex increases in heart-rate induced by perfusing the hind leg of the rat with soluti...
7143699 - Clinical evaluation of left ventricular performance in patients with myocardial infarct...
10786869 - The pathological status of exercise dependence.
16867249 - Addition of tanshinone iia to uw solution decreases skeletal muscle ischemia-reperfusio...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical physiology (Oxford, England)     Volume:  19     ISSN:  0144-5979     ISO Abbreviation:  Clin Physiol     Publication Date:  1999 Jul 
Date Detail:
Created Date:  1999-10-12     Completed Date:  1999-10-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8309768     Medline TA:  Clin Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  294-9     Citation Subset:  IM    
Affiliation:
Department of Medicine, University of Oulu, Finland.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Antagonists / pharmacology
Adult
Arm / physiology*
Autonomic Nervous System / physiology*
Blood Pressure / physiology
Electrocardiography
Exercise / physiology*
Exercise Test
Heart Rate / drug effects,  physiology*
Humans
Leg / physiology*
Male
Oxygen Consumption / physiology
Propranolol / pharmacology
Vagus Nerve / physiology
Chemical
Reg. No./Substance:
0/Adrenergic beta-Antagonists; 525-66-6/Propranolol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Induction of acute metabolic acid/base changes in humans.
Next Document:  Comparison of two methacholine challenge methods using Spira-2 or Mefar dosimeter.