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Exercise-induced hemoconcentration in heart failure due to dilated cardiomyopathy
P Agostoni1, K Wasserman, M Guazzi
1Istituto di Cardiologia dell' Università degli Studi, Milan, Italy.
The American Journal of Cardiology
|March 12, 1999
Summary
Exercise-induced hemoconcentration boosts oxygen delivery to muscles, especially beneficial for heart failure patients. This process involves fluid shifting out of blood vessels, not red blood cell release from the spleen.
Area of Science:
- Physiology
- Cardiovascular Science
- Exercise Physiology
Background:
- Exercise-induced hemoconcentration is a physiological response to physical exertion.
- This mechanism can enhance oxygen delivery to working muscles.
- Its role in cardiovascular conditions like heart failure warrants investigation.
Purpose of the Study:
- To investigate the phenomenon of exercise-induced hemoconcentration.
- To determine the contribution of hemoconcentration to oxygen transport during exercise.
- To elucidate the underlying mechanisms of hemoconcentration in normal individuals and heart failure patients.
Main Methods:
- Studied 50 normal subjects and 50 patients with congestive heart failure.
- Measured hemoglobin levels at peak exercise.
- Assessed plasma protein changes to understand fluid shifts.
Main Results:
- Hemoglobin increased by 7% in normal subjects and 5% in heart failure patients at peak exercise.
- The percentage increase in hemoglobin was comparable to the increase in plasma proteins.
- This suggests fluid flux from the vascular bed, not splenic red blood cell release.
Conclusions:
- Exercise-induced hemoconcentration increases blood oxygen content, aiding muscle perfusion.
- Fluid shifts out of the vascular bed, driven by oncotic forces linked to lactate, are the primary cause.
- This mechanism is particularly relevant and potentially beneficial in managing heart failure.