Erythropoiesis with endurance training: dynamics and mechanisms

The purpose of the present study was to characterize the progression of red blood cell volume (RBCV) expansion and potential volumetric and endocrine regulators of erythropoiesis during endurance training (ET). Nine healthy, untrained volunteers (age = 27 ± 4 yr) underwent supervised ET consisting of 3–4 × 60 min cycle ergometry sessions per week for 8 wk. Plasma volume (PV), RBCV, and overnight fasting hematological markers were determined before and at weeks 2, 4, and 8 of ET. In addition, plasma erythropoietin (EPO), cortisol, copeptin, and proatrial natriuretic peptide concentrations were measured during a 3-h morning period at baseline and postexercise at weeks 1 and 8. PV increased from baseline (2,405 ± 335 ml) at weeks 2, 4, and 8 (+374 ± 194, +505 ± 156, and +341 ± 160 ml, respectively, P < 0.001). Increases in RBCV from baseline (1,737 ± 442 ml) were manifested at week 4 (+109 ± 114 ml, P = 0.030) and week 8 (+205 ± 109 ml, P = 0.001). Overnight fasting plasma EPO concentration increased from baseline (11.3 ± 4.8 mIU/ml) at week 2 (+2.5 ± 2.8 mIU·ml−1, P = 0.027) and returned to baseline concentration at weeks 4 and 8. Higher 3-h-postexercise EPO concentration was observed at week 1 (11.6 mIU/ml) compared with week 8 (8.4 ± 3.9 mIU/ml, P = 0.009) and baseline (9.0 ± 4.2 mIU/ml, P = 0.019). Linear relationships between EPO concentration and hematocrit (β = −56.2, P < 0.001) and cortisol (β = 0.037, P < 0.001) were detected throughout the ET intervention. In conclusion, ET leads to mild, transient increases in circulating EPO concentration, concurring with early PV expansion and lowered hematocrit, preceding gradual RBCV enhancement.

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Red Blood Cell Volume, Plasma Volume and Total Blood Volume in Healthy Elderly Men and Women Aged 64 to 100

10.21236/ada360250 ◽

1992 ◽

Author(s):

C. R. Valeri ◽

Linda E. Pivacek ◽

Hiliary Siebens ◽

Mark D. Altschule

Keyword(s):

Blood Cell ◽

Cell Volume ◽

Blood Volume ◽

Plasma Volume ◽

Red Blood Cell ◽

Total Blood Volume ◽

Elderly Men ◽

Total Blood ◽

Men And Women ◽

Healthy Elderly

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Blood Volume Changes during Three-Week Residence at High Altitude

Clinical Chemistry ◽

10.1093/clinchem/16.1.7 ◽

1970 ◽

Vol 16 (1) ◽

pp. 7-14 ◽

Cited By ~ 14

Author(s):

L G Myhre ◽

D B Dill ◽

F G Hall ◽

D K Brown

Keyword(s):

Carbon Monoxide ◽

Blood Cell ◽

High Altitude ◽

Cell Volume ◽

Plasma Volume ◽

Red Blood Cell ◽

Hemoglobin Concentration ◽

Red Cell ◽

Volume Changes ◽

Cell Volumes

Abstract Circulating red blood cell volumes were determined by the carbon monoxide method, and plasma volumes were calculated in four men 20, 29, 71, and 75 years old, and two women 29 years of age before, during, and after exposure to an altitude of 3800 m. In the four youngest subjects there were early increases in hemoglobin concentration during the first days at the stated altitude attributed to decreases in plasma volume. At the same time, hemoglobin concentration decreased and plasma volume increased in the oldest subject. Red cell volumes were slow to change, and it was concluded that 3 weeks or more of exposure to this altitude are required to affect significantly the red cell volume in man.

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Plasma volume, red cell volume, and thoracic duct lymph flow in hypothermia

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1977.233.5.h605 ◽

1977 ◽

Vol 233 (5) ◽

pp. H605-H612 ◽

Cited By ~ 3

Author(s):

R. Y. Chen ◽

S. Chien

Keyword(s):

Blood Cell ◽

Cell Volume ◽

Plasma Volume ◽

Red Blood Cell ◽

Thoracic Duct ◽

Protein Concentration ◽

Lymph Flow ◽

Thoracic Duct Lymph ◽

Circulating Blood Volume ◽

Duct Lymph

The effects of hypothermia on plasma volume (125I-albumin), red blood cell volume (51 Cr-RBC), and capillary permeability (thoracic duct lymph flow and protein concentration) were determined on dogs anesthetized with pentobarbital, paralyzed with succinylcholine, and mechanically ventilated. Red blood cell volume and plasma protein concentration did not change significantly after cooling. Reductions in plasma volume and total plasma proteins indicate that whole plasma was excluded from the effective circulating blood volume. Except for a lesser increase in hematocrit, chronically splenectomized dogs showed essentially the same changes as normal dogs in response to hypothermia. Following application of ice bags, there was a biphasic response in lymph flow. The early increase in lymph flow accompanying a slight decrease in plasma volume was attributable to transcapillary fluid loss into interstitial space, probably due to cold-induced sympathetic activity. The later decrease in lymph flow in hypothermia resulted from a decrease of lymph production secondary to a decrease in available capillary diffusion area. This decrease in lymph flows and the continued reduction in plasma volume suggest an intravascular sequestration of whole plasma.

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Regulation of blood volume in lowlanders exposed to high altitude

Journal of Applied Physiology ◽

10.1152/japplphysiol.00118.2017 ◽

2017 ◽

Vol 123 (4) ◽

pp. 957-966 ◽

Cited By ~ 34

Author(s):

Christoph Siebenmann ◽

Paul Robach ◽

Carsten Lundby

Keyword(s):

Blood Cell ◽

High Altitude ◽

Cell Volume ◽

Blood Volume ◽

Plasma Volume ◽

Red Blood Cell ◽

Hemoglobin Concentration ◽

Circulating Blood Volume ◽

Oxyhemoglobin Saturation ◽

Physiological Relevance

Humans ascending to high altitude (HA) experience a reduction in arterial oxyhemoglobin saturation and, as a result, arterial O2content ([Formula: see text]). As HA exposure extends, this reduction in [Formula: see text] is counteracted by an increase in arterial hemoglobin concentration. Initially, hemoconcentration is exclusively related to a reduction in plasma volume (PV), whereas after several weeks a progressive expansion in total red blood cell volume (RCV) contributes, although often to a modest extent. Since the decrease in PV is more rapid and usually more pronounced than the expansion in RCV, at least during the first weeks of exposure, a reduction in circulating blood volume is common at HA. Although the regulation of hematological responses to HA has been investigated for decades, it remains incompletely understood. This is not only related to the large number of mechanisms that could be involved and the complexity of their interplay but also to the difficulty of conducting comprehensive experiments in the often secluded HA environment. In this review, we present our understanding of the kinetics, the mechanisms and the physiological relevance of the HA-induced reduction in PV and expansion in RCV.

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Changes in red blood cell volume, plasma volume, and total blood volume after autologous blood collections

Transfusion ◽

10.1111/j.1537-2995.2008.01768.x ◽

2008 ◽

Vol 48 (7) ◽

pp. 1524-1526 ◽

Cited By ~ 6

Keyword(s):

Blood Cell ◽

Cell Volume ◽

Blood Volume ◽

Plasma Volume ◽

Red Blood Cell ◽

Autologous Blood ◽

Total Blood Volume ◽

Total Blood

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Cerebral blood flow, blood volume, and brain tissue hematocrit during isovolemic hemodilution with hetastarch in rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1992.263.1.h75 ◽

1992 ◽

Vol 263 (1) ◽

pp. H75-H82 ◽

Cited By ~ 7

Author(s):

M. M. Todd ◽

J. B. Weeks ◽

D. S. Warner

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Blood Cell ◽

Cell Volume ◽

Brain Tissue ◽

Blood Volume ◽

Plasma Volume ◽

Red Blood Cell ◽

Isovolemic Hemodilution ◽

Blood Cell And Plasma

The influence of isovolemic hemodilution with 6% hetastarch [hematocrits (Hct) ranging from 43 to 20%] on cerebral blood flow (CBF), cerebral red blood cell and plasma volumes, total cerebral blood volume (CBV), and cerebral Hct was examined in normothermic, normocarbic, halothane-anesthetized Sprague-Dawley rats. CBF was measured via the indicator-fractionation method ([3H]nicotine), red blood cell volume was measured using 99mTc-labeled red blood cells, while plasma volume was measured using [14C]dextran. Brain tissue was fixed in situ by microwave irradiation. All data plots (e.g., CBF vs. Hct) were fitted by linear regression methods. Hemodilution was associated with a progressive increase in forebrain CBF (from a fitted value of 78 ml.100 g-1.min-1 at Hct = 43%, to 171 ml.100 g-1.min-1 at 20%). Cerebral plasma volume also rose, while red blood cell volume decreased. Total CBV (i.e., the sum of red blood cell and plasma volumes) increased in parallel with CBF (from 2.51 ml/100 g at Hct = 43 to 4.94 ml/100 g at Hct = 20%). This increase is larger than can be explained by a simple increase in the diameter of arterial/arteriolar resistance vessels and may be due to either capillary recruitment or to an increase in the volume of postarteriolar structures. Calculated cerebral tissue hematocrit decreased. The magnitude of this decrease was larger than the reduction in arterial Hct; the ratio of cerebral to arterial Hct decreased from 0.780 at an arterial Hct equaling 43% to 0.458 at Hct equaling 20%.(ABSTRACT TRUNCATED AT 250 WORDS)

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