Key result
Exercise in the supine position increased cardiac output by 85.7% with a disproportionate redistribution of blood flow towards the lower body, while changing from prone to supine altered regional pulmonary blood flow.
Why the study?
Do changes in posture and exercise alter systemic and pulmonary blood flow distribution in healthy adult volunteers?
Cross-Sectional (n=22)
No
Do changes in posture and exercise alter systemic and pulmonary blood flow distribution in healthy adult volunteers?
Effect estimate: 85.7% increase
Absolute Event Rate: 6005% vs 3208%
p-value: p=<0.0001
Hemodynamic assessments performed at rest in the supine position do not fully capture physiological blood flow distribution, which redistributes significantly to the lower body and dependent lung segments during exercise and postural changes.
Resting supine hemodynamics may underestimate dynamic flow redistribution; hypothesis-generating for posture- and exercise-adjusted models in health and disease.
Hemodynamics are usually evaluated in the supine position at rest. This is only a snapshot of an individual's daily activities. This study describes circulatory adaptation, as assessed by magnetic resonance imaging, to changes in position and exercise. Phase contrast magnetic resonance imaging of blood flow within systemic and pulmonary arteries and veins was performed in 24 healthy volunteers at rest in the prone and supine position and with bicycle exercise in the supine position. No change was seen in systemic blood flow when moving from prone to supine. Exercise resulted in an increased percentage of cardiac output towards the lower body. Changes in position resulted in a redistribution of blood flow within the left lung--supine positioning resulted in decreased blood flow to the left lower pulmonary vein. With exercise, both the right and left lower lobes received increased blood flow, while the upper lobes received less.
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Wong et al. (2014) conducted a cross-sectional in Healthy volunteers (n=22). Exercise and posture changes vs. Supine at rest was evaluated on Ascending aorta (AAO) blood flow (cardiac output) (85.7% increase, p=<0.0001). Exercise in the supine position increased cardiac output by 85.7% with a disproportionate redistribution of blood flow towards the lower body, while changing from prone to supine altered regional pulmonary blood flow.
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