Regulation of Red Blood Cell Volume with Exercise Training.
Level 5 - mechanism / opinion, no new human data
Narrative physiological review without systematic search methodology
PubMed 30549016 · doi:10.1002/cphy.c180004
What was done
Narrative review synthesizing the physiological mechanisms regulating red blood cell volume (RBCV) expansion following acute and chronic endurance training. The abstract outlines physiological models, including the "critmeter" theory and endocrine responses (angiotensin II, vasopressin, catecholamines, cortisol), without reporting a systematic search protocol or sample sizes.
What was found
The review notes that endurance champions may have 40% higher RBCV than controls, and regular training increases RBCV by up to 10% after months of exercise in healthy individuals. Initial training sessions induce plasma volume expansion, causing transient hemodilution that stimulates renal erythropoietin (EPO) production via juxtamedullary oxygen sensors. Acute exercise also transiently elevates angiotensin II, vasopressin, catecholamines, and cortisol, which promote EPO production and bone marrow red blood cell release alongside bone marrow hyperplasia.
Why it matters
Synthesizes the hormonal and hematological feedback mechanisms that drive red blood cell volume expansion and subsequent improvements in maximal oxygen uptake following endurance training.
Limits
The abstract describes a narrative review without original clinical trial data, systematic search parameters, or study counts. No statistical precision (such as confidence intervals) or heterogeneity metrics are reported.
Cited by
- supports Endurance exercise increases total blood volume and the number of red blood cells in the body.