Role of heart rate and stroke volume during muscle metaboreflex-induced cardiac output increase: differences between activation during and after exercise

We hypothesized that the role of stroke volume (SV) in the metaboreflex-induced cardiac output (CO) increase was blunted when the metaboreflex was stimulated by exercise muscle ischemia (EMI) compared with post-exercise muscle ischemia (PEMI), because during EMI heart rate (HR) increases and limits...

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Bibliographic Details
Published in:The journal of physiological sciences 2011-09, Vol.61 (5), p.385-394, Article 385
Main Authors: Crisafulli, Antonio, Piras, Francesco, Filippi, Michele, Piredda, Carlo, Chiappori, Paolo, Melis, Franco, Milia, Raffaele, Tocco, Filippo, Concu, Alberto
Format: Article
Language:English
Subjects:
Adult
Blood Pressure - physiology
Exercise - physiology
Heart Rate - physiology
Hemodynamics - physiology
Humans
Male
Middle Aged
Muscle, Skeletal - physiology
Original Paper
Reflex - physiology
Stroke Volume - physiology
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Summary:We hypothesized that the role of stroke volume (SV) in the metaboreflex-induced cardiac output (CO) increase was blunted when the metaboreflex was stimulated by exercise muscle ischemia (EMI) compared with post-exercise muscle ischemia (PEMI), because during EMI heart rate (HR) increases and limits diastolic filling. Twelve healthy volunteers were recruited and their hemodynamic responses to the metaboreflex evoked by EMI, PEMI, and by a control dynamic exercise were assessed. The main finding was that the blood pressure increment was very similar in the EMI and PEMI settings. In both conditions the main mechanism used to raise blood pressure was a CO elevation. However, during the EMI test CO was increased as a result of HR elevation whereas during the PEMI test CO was increased as a result of an increase in SV. These results were explainable on the basis of the different HR behavior between the two settings, which in turn led to different diastolic time and myocardial performance.
ISSN:1880-6546
1880-6562
DOI:10.1007/s12576-011-0163-x