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Red blood cells in sports: effects of exercise and training on oxygen supply by red blood cells.

Mairbäurl H - Front Physiol (2013)

Bottom Line: Trained athletes, particularly in endurance sports, have a decreased hematocrit, which is sometimes called "sports anemia." This is not anemia in a clinical sense, because athletes have in fact an increased total mass of red blood cells and hemoglobin in circulation relative to sedentary individuals.The slight decrease in hematocrit by training is brought about by an increased plasma volume (PV).Together, these adjustments cause a decrease in the average age of the population of circulating red blood cells in trained athletes.

View Article: PubMed Central - PubMed

Affiliation: Medical Clinic VII, Sports Medicine, University of Heidelberg Heidelberg, Germany.

ABSTRACT
During exercise the cardiovascular system has to warrant substrate supply to working muscle. The main function of red blood cells in exercise is the transport of O2 from the lungs to the tissues and the delivery of metabolically produced CO2 to the lungs for expiration. Hemoglobin also contributes to the blood's buffering capacity, and ATP and NO release from red blood cells contributes to vasodilation and improved blood flow to working muscle. These functions require adequate amounts of red blood cells in circulation. Trained athletes, particularly in endurance sports, have a decreased hematocrit, which is sometimes called "sports anemia." This is not anemia in a clinical sense, because athletes have in fact an increased total mass of red blood cells and hemoglobin in circulation relative to sedentary individuals. The slight decrease in hematocrit by training is brought about by an increased plasma volume (PV). The mechanisms that increase total red blood cell mass by training are not understood fully. Despite stimulated erythropoiesis, exercise can decrease the red blood cell mass by intravascular hemolysis mainly of senescent red blood cells, which is caused by mechanical rupture when red blood cells pass through capillaries in contracting muscles, and by compression of red cells e.g., in foot soles during running or in hand palms in weightlifters. Together, these adjustments cause a decrease in the average age of the population of circulating red blood cells in trained athletes. These younger red cells are characterized by improved oxygen release and deformability, both of which also improve tissue oxygen supply during exercise.

No MeSH data available.


Related in: MedlinePlus

Effects of hemoglobin concentration and pH, CO2, 2,3-DPG and temperature on blood oxygen content and on Hb-O2 affinity. Oxygen dissociation curves (ODC) were calculated with the equation by Severinghaus (1979) using decreased, normal, and increased P50 values. Oxygen content was calculated from SO2 and normal and decreased hemoglobin concentrations assuming that 1 g H binds 1.34 ml of O2. The insert indicates that an increase in pH, and a decrease in CO2, 2,3-DPG and temperature shifts the ODC to the left (red arrows and curves), whereas acidosis and increased CO2, 2,3-DPG and temperature shift the ODCs to the right.
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Figure 1: Effects of hemoglobin concentration and pH, CO2, 2,3-DPG and temperature on blood oxygen content and on Hb-O2 affinity. Oxygen dissociation curves (ODC) were calculated with the equation by Severinghaus (1979) using decreased, normal, and increased P50 values. Oxygen content was calculated from SO2 and normal and decreased hemoglobin concentrations assuming that 1 g H binds 1.34 ml of O2. The insert indicates that an increase in pH, and a decrease in CO2, 2,3-DPG and temperature shifts the ODC to the left (red arrows and curves), whereas acidosis and increased CO2, 2,3-DPG and temperature shift the ODCs to the right.

Mentions: The biological significance of O2 transport by Hb is well-illustrated by anemia where decreased Hb also decreases exercise performance despite a compensatory increase in cardiac output (Ledingham, 1977; Carroll, 2007), and by improved aerobic performance upon increasing total Hb (Berglund and Hemmingson, 1987). The O2 dissociation curves in Figure 1 indicate the advantage of normal vs. anemic Hb showing that the O2 content in blood varies with the Hb concentration in blood at any given O2 partial pressure (PO2). Not only its amount but also the functional properties of Hb affect performance. This is illustrated by the observation that an increased Hb-O2 affinity favors O2 loading in the lung and survival in an hypoxic environment (Eaton et al., 1974; Hebbel et al., 1978), whereas a decreased Hb-O2 affinity favors the release of O2 from the Hb molecule in support of oxidative phosphorylation when the ATP demand is high, such as in exercising skeletal muscle (for a recent review see Mairbäurl and Weber, 2012).


Red blood cells in sports: effects of exercise and training on oxygen supply by red blood cells.

Mairbäurl H - Front Physiol (2013)

Effects of hemoglobin concentration and pH, CO2, 2,3-DPG and temperature on blood oxygen content and on Hb-O2 affinity. Oxygen dissociation curves (ODC) were calculated with the equation by Severinghaus (1979) using decreased, normal, and increased P50 values. Oxygen content was calculated from SO2 and normal and decreased hemoglobin concentrations assuming that 1 g H binds 1.34 ml of O2. The insert indicates that an increase in pH, and a decrease in CO2, 2,3-DPG and temperature shifts the ODC to the left (red arrows and curves), whereas acidosis and increased CO2, 2,3-DPG and temperature shift the ODCs to the right.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824146&req=5

Figure 1: Effects of hemoglobin concentration and pH, CO2, 2,3-DPG and temperature on blood oxygen content and on Hb-O2 affinity. Oxygen dissociation curves (ODC) were calculated with the equation by Severinghaus (1979) using decreased, normal, and increased P50 values. Oxygen content was calculated from SO2 and normal and decreased hemoglobin concentrations assuming that 1 g H binds 1.34 ml of O2. The insert indicates that an increase in pH, and a decrease in CO2, 2,3-DPG and temperature shifts the ODC to the left (red arrows and curves), whereas acidosis and increased CO2, 2,3-DPG and temperature shift the ODCs to the right.
Mentions: The biological significance of O2 transport by Hb is well-illustrated by anemia where decreased Hb also decreases exercise performance despite a compensatory increase in cardiac output (Ledingham, 1977; Carroll, 2007), and by improved aerobic performance upon increasing total Hb (Berglund and Hemmingson, 1987). The O2 dissociation curves in Figure 1 indicate the advantage of normal vs. anemic Hb showing that the O2 content in blood varies with the Hb concentration in blood at any given O2 partial pressure (PO2). Not only its amount but also the functional properties of Hb affect performance. This is illustrated by the observation that an increased Hb-O2 affinity favors O2 loading in the lung and survival in an hypoxic environment (Eaton et al., 1974; Hebbel et al., 1978), whereas a decreased Hb-O2 affinity favors the release of O2 from the Hb molecule in support of oxidative phosphorylation when the ATP demand is high, such as in exercising skeletal muscle (for a recent review see Mairbäurl and Weber, 2012).

Bottom Line: Trained athletes, particularly in endurance sports, have a decreased hematocrit, which is sometimes called "sports anemia." This is not anemia in a clinical sense, because athletes have in fact an increased total mass of red blood cells and hemoglobin in circulation relative to sedentary individuals.The slight decrease in hematocrit by training is brought about by an increased plasma volume (PV).Together, these adjustments cause a decrease in the average age of the population of circulating red blood cells in trained athletes.

View Article: PubMed Central - PubMed

Affiliation: Medical Clinic VII, Sports Medicine, University of Heidelberg Heidelberg, Germany.

ABSTRACT
During exercise the cardiovascular system has to warrant substrate supply to working muscle. The main function of red blood cells in exercise is the transport of O2 from the lungs to the tissues and the delivery of metabolically produced CO2 to the lungs for expiration. Hemoglobin also contributes to the blood's buffering capacity, and ATP and NO release from red blood cells contributes to vasodilation and improved blood flow to working muscle. These functions require adequate amounts of red blood cells in circulation. Trained athletes, particularly in endurance sports, have a decreased hematocrit, which is sometimes called "sports anemia." This is not anemia in a clinical sense, because athletes have in fact an increased total mass of red blood cells and hemoglobin in circulation relative to sedentary individuals. The slight decrease in hematocrit by training is brought about by an increased plasma volume (PV). The mechanisms that increase total red blood cell mass by training are not understood fully. Despite stimulated erythropoiesis, exercise can decrease the red blood cell mass by intravascular hemolysis mainly of senescent red blood cells, which is caused by mechanical rupture when red blood cells pass through capillaries in contracting muscles, and by compression of red cells e.g., in foot soles during running or in hand palms in weightlifters. Together, these adjustments cause a decrease in the average age of the population of circulating red blood cells in trained athletes. These younger red cells are characterized by improved oxygen release and deformability, both of which also improve tissue oxygen supply during exercise.

No MeSH data available.


Related in: MedlinePlus