Can too much exercise cause ischemia?

Depends: Healthy people cannot get ischemia. You must have blocked arteries for that. If you're otherwise healthy (as most 33 year olds are), you could climb mt everest and you might freeze to death but you wouldn't get ischemia.

Yes: As we in pathology use the word "ischemia", it simply means less total blood flow than the organ is requesting. Especially while you're conditioning your heart, you push it to the maximum and the organs request more -- the ischemia is reflected in increased lactic acid levels in the blood. Clinicians use the term for "infarction", in which tissue dies -- won't happen from exercise.