There has been some experimental work done recently in producing more red blood cells by heating older yellow bone marrow in either Japan or China.
Electrotherapy can be used to heat the bone marrow of older patients, decreacing the fat content of unproductive yellow bone matrow, to become red blood cell producing red bone marrow, by using diathermy principles.
'This action heat upon bone marrow increaces the number of red blood cells and the output of hemoglobin.'
page 342
Handbook of Electrotherapy for Practitioners and Students
By Burt Grover Brothers, published Philadelphia, F. A. Davis Company, 1922.
Heating bone marrow with bone thermometry is documented at cite 162 at:
http://www.ismrm.org/15/program_files/TueTP02.htm
Differences in yellow and red bone marrow are detailed at:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3529711/
Discussing the fatty infiltration of yellow bone marrow at:
https://www.ncbi.nlm.nih.gov/pubmed/12840883