Related Experiment Video
Updated: May 30, 2026

Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine
Published on: February 9, 2016
Role of heart rate and stroke volume during muscle metaboreflex-induced cardiac output increase: differences between
Antonio Crisafulli1, Francesco Piras, Michele Filippi
1Section of Human Physiology, Department of Science Applied to Biological Systems, University of Cagliari, Via Porcell 4, 09124 Cagliari, Italy. crisafulli@tiscali.it
Abstract:
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.
More Related Videos
Related Concept Videos
Cardiac Output II: Effect of Stroke Volume on Cardiac Output
Preload
Preload refers to the initial elongation of the cardiac myocytes before contraction and is related to the volume of blood filling the heart at the end of diastole, or end-diastolic volume. The...
Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be met...
Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
Pathophysiology of Cardiac Performance
Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart rate...
Cardiac Output and Stroke Volume
In an average resting adult male, the typical cardiac output averages...

