It is well known that the donation of a unit of blood (450ml) stimulates the natural production of erythropoietin (hEPO), which doubles or triples for the duration of 2-4 weeks, until the Hb-mass recovers the initial values. 

The same happens at altitude: the daily natural production of hEPO increases from 300-500U at sea level (Med Sci Sports 1992; 2:16-20) to 600-900U for subjects residing above 2000m a.s.l.: the result is an increase in Hb-mass of 4-6% after a 3 weeks sojourn (J Appl Physiol 2006; 100:1938-1945, Scand J Med Sci Sports 2012; 22:95-103). 

The numerous and surprising clinical observations that administration of rhEPO improves the cognitive functions of patients were always attributed to the increase in Hb and thus to a better oxygenation of organs, including the brain. 
The discovery of EPO receptors in the brain and subsequent research has shown that erythropoietin has powerful protective action with regards to brain damage (Curr Pharm Biotechnol 2005; 6:65-79, Neurotherapeutics 2009; 6:108-127). 

Patients with neurological disorders such as schizophrenia, multiple sclerosis, premature births have shown significant improvements in cognitive and neurological disorders after treatment with rhEPO. 
A recent study with healthy volunteers showed improved memory function after a single dose of rhEPO (J Neurosci 2007, 27:2788-2792), later confirmed by studies by Miskoviac that observed activation in brain areas related to short and long term memory a few days after the administration of rhEPO (Exp Brain Res 2008, 184:313-321). 
The same author has also demonstrated improvements in mood in healthy subjects treated with EPO (Neuropsycopharmacology 2008, 33:611-618). 

The nasal administration of rhEPO has been recently used in the treatment of strokes (ScientificWourldJournal 2009, 15:970-981, Drug Metab Drug Interact 2011). 

Recent studies have demonstrated the significant protective effects of EPO in case of ischemic heart disease and chronic heart failure, through stimulation of mitochondrial biogenesis in cardiac cells (Circ Res 2010, 106:1722-1730) and angiogenesis (formation of new blood vessels). 

The subjective improvements in memory, mood, psycho-physical efficiency and motor coordination, which are often reported by individuals who have donated blood or stayed in the mountains in the weeks before, confirm the results of research in recent years and may be used by authorities to promote blood donations. 

Athletes too may benefit from blood donations, as the effect is similar to the stay at altitude, with a much lower economic cost, even though under the scrutiny of Sports Authority as a "hematologic manipulation"...