If a person loses enough blood to become moderately anemic, how long does it take for the red blood cell count to return to normal? I mean roughly...would it be on the order of days, weeks, or...? Is daily iron intake a typical limiting factor in this process?
The second question third paragraph. http://www.runnersweb.com/running/r...ning/news/rw_news_20040809_BloodDonation.html Now this is only a 'rough estimate' for only 450mL of blood loss. Losing more or less blood will obviously effect the recovery time and also the rate of regeneration. Blood is on a positive feedback so lower oxygen being sent to the body will cause more blood cells to be created etc. (AFAIK) I'm not exactly sure about the iron question but I'll take a stab at it. Iron's function in the blood specifically has to do with the hemeoglobin. So the blood will still be created but you will still remain anemic because your blood can not properly transfer oxygen. It is important to keep your iron intake up to ensure that this doesn't occur.
Production of erythrocytes takes about 4 days, and is stimulated by hypoxia, not iron intake: http://faculty.ucc.edu/biology-potter/life_cycle_of_the_erythrocyte.htm The physiological 'iron cycle' is not that well understood: http://www.ncbi.nlm.nih.gov/pubmed/17014365 http://bmb.oxfordjournals.org/cgi/pdf_extract/37/1/25 http://scienceweek.com/2005/sb050218-4.htm
that statement is factually not correct but I do think they are talking not of erythropoesis , which is 100-120 days............they are referring to recruitment from the marrow of mature RBC's which is about 4 days. The cells develop in the bone marrow and circulate for about 100–120 days in the body before their components are recycled by macrophages. The total turnover for anemia is what matter most. And it can be shortened with meds and other methods we surgeons use.
Err, well erythropoiesis takes around 7 days to complete. They are released from the bone marrow as reticulocytes and it takes around 2 of those days for it to mature into erythrocytes. The life-cycle of the erythrocyte is generally accepted as 100-120 days. At which point the get sorta 'eaten' up mostly by the spleen. This is only part of the problem though because you lose a lot more than just erythrocytes when you bleed out... they all will get regenerated but erythrocytes is only part of the problem. EDIT: As well I noticed a mistake I made in my first post, I said positive feedback, it should be negative feedback. I explained it correctly just used the wrong feedback term :rofl:. As well it is for the most part controlled by the kidney, which regulates the production of blood cells based on how much oxygen it is receiving. So if you lose blood it will receive less oxygen therefore increasing the amount of blood cells being produced.
Yes, when you lose blood you definitely lose your iron as well. In that case, iron deficiency in diet would limit recovery and you'd get a clinical picture of microcytic hypochromic anaemia. That's similar to occult losses of blood, such as from the Gastrointestinal tract that typically cause iron deficiency anaemia. On the other hand, with a case of haemochromatosis, you'd see a typical picture of normocytic normochromic anaemia. Timeline for recovery is already stated in above posts.