Heart rate during exercise with leg vascular occlusion in spinal cord-injured humans
1 Sports Medicine Research Unit, Department of Rheumatology H, Bispebjerg Hospital, DK-2400 Copenhagen NV; Departments of 2 Anesthesia and 3 Internal Medicine TTA, Copenhagen Muscle Research Center, Rigshospitalet, DK-2100 Copenhagen; and 4 Department of Medical Physiology, Panum Institute, Univ...
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Published in | Journal of applied physiology (1985) Vol. 86; no. 3; pp. 806 - 811 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Bethesda, MD
Am Physiological Soc
01.03.1999
American Physiological Society |
Subjects | |
Online Access | Get full text |
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Summary: | 1 Sports Medicine Research
Unit, Department of Rheumatology H, Bispebjerg Hospital, DK-2400
Copenhagen NV; Departments of
2 Anesthesia and
3 Internal Medicine TTA,
Copenhagen Muscle Research Center, Rigshospitalet, DK-2100 Copenhagen;
and 4 Department of Medical
Physiology, Panum Institute, University of Copenhagen, DK-2200
Copenhagen N, Denmark
Feed-forward and
feedback mechanisms are both important for control of the heart rate
response to muscular exercise, but their origin and relative importance
remain inadequately understood. To evaluate whether humoral mechanisms
are of importance, the heart rate response to electrically induced
cycling was studied in participants with spinal cord injury (SCI) and
compared with that elicited during volitional cycling in able-bodied
persons (C). During voluntary exercise at an oxygen uptake of ~1
l/min, heart rate increased from 66 ± 4 to 86 ± 4 (SE)
beats/min in seven C, and during electrically induced exercise at a
similar oxygen uptake in SCI it increased from 73 ± 3 to 110 ± 8 beats/min. In contrast, blood pressure increased only in C (from 88 ± 3 to 99 ± 4 mmHg), confirming that, during exercise, blood
pressure control is dominated by peripheral neural feedback mechanisms.
With vascular occlusion of the legs, the exercise-induced increase in
heart rate was reduced or even eliminated in the electrically
stimulated SCI. For C, heart rate tended to be lower than during
exercise with free circulation to the legs. Release of the cuff
elevated heart rate only in SCI. These data suggest that humoral
feedback is of importance for the heart rate response to exercise and
especially so when influence from the central nervous system and
peripheral neural feedback from the working muscles are impaired or
eliminated during electrically induced exercise in individuals with SCI.
blood pressure; feedback mechanism; central command
Deceased. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 8750-7587 1522-1601 |
DOI: | 10.1152/jappl.1999.86.3.806 |