Anemia in the elderly

Like a lot of other things it has a bigger impact on older folks. Any condition where cardiac function is compromised, heart failure for example, will likely be made worse by anemia.
http://emedicine.medscape.com/article/1339998-overview
Heart failure example:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3569049/
If you have iron deficiency anemia for example, get it treated, but don't assume that you have it and treat it yourself. The reasons for it can be complex and self treating can be worse than the condition.

Jim