There are some cancers that will affect the RBC count. When that happens, one of the major side effects is a listless tiredness. That's because the Red Cells carry oxygen. Oxygen not getting anywhere means the brain is certainly not getting enough and reserves and energy levels go down. Just ask anyone who has that kind of bone related cancer. It can be painful and it can be very debilitating in other ways depending what else is affected by the decrease in red cells. Often the Neutrophils can be affected along with a general distress in the Cell count of the blood. That means that you are prone to getting life threatening fevers. That really complicated your life, because while taking treatment for that (using very powerful antibiotics), you may be forced into taking flu shots which you may not agree with.
Bad news abounds when all this takes place. Likely other things are affected as well, like the production of immature cells of every kind.
(1) Digestive System gets nutrients (good) from food and hands it over to the blood and Circulatory System then carries those nutrients where they need to go. (2) Filters out waste from food and pushes it through intestines and out the body (and you know how and where it gets out).
