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Fixed Volume or Fixed Pressure: A Murine Model of Hemorrhagic Shock
Published on: June 6, 2011
Hemorheological alterations related to training and overtraining
Jean-Frédéric Brun1, Emmanuelle Varlet-Marie, Philippe Connes
1Service Central de Physiologie Clinique, Unité d'Exploration Métabolique, CHU Lapeyronie, Montpellier, France. jean-frederic.brun@laposte.net
Biorheology
|August 5, 2010
Summary
Exercise impacts blood flow properties in three phases: initial thickening, followed by autohemodilution, and long-term hemorheologic fitness adaptations. Overtraining can negatively affect blood viscosity.
Area of Science:
- Clinical Hemorheology
- Exercise Physiology
- Sports Medicine
Background:
- Blood rheology, the study of blood flow properties, is significantly influenced by muscular activity.
- Over the past two decades, research has established a triphasic response of blood rheology to exercise.
Purpose of the Study:
- To review the short-term and long-term effects of exercise on blood rheology.
- To discuss the concept of 'hemorheologic fitness' and adaptations to training.
- To highlight specific phenomena like paradoxical red blood cell deformability changes and overtraining effects.
Main Methods:
- Review of existing literature on blood rheology and exercise.
- Analysis of short-term (acute exercise) and long-term (training) adaptations.
- Examination of hematocrit, plasma viscosity, and red blood cell rheology (deformability, aggregation).
Main Results:
- Acute exercise initially increases blood viscosity due to elevated hematocrit and plasma viscosity.
- A 24-hour period post-exercise shows 'autohemodilution', normalizing viscosity.
- Long-term training leads to 'hemorheologic fitness' characterized by lower hematocrit, plasma volume expansion, and improved red blood cell function; overtraining is linked to increased plasma viscosity.
Conclusions:
- Exercise induces complex, time-dependent changes in blood rheology.
- Training adaptations promote favorable hemorheologic profiles, but overtraining poses risks.
- Further research is needed due to the heterogeneity of exercise modes and their rheological impacts.
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