Dream about doing a marathon is a sign for your endurance and willpower. You need to concentrate harder on a problem in your life. You need to spring into action. This points to the Self. You need to let go of the past or certain negative behaviors.
Doing a marathon dream represents some deep fear. You are saying one thing, but you actually mean something else. You are harvesting or babying a new idea, creation or project. Your dream points to a person or may even be a pun on something that is seedy. You need to be careful not to be too forceful.
If you dreamt about doing a marathon:
Money matters might require your attention today. Unusual expenses may have depleted your reserves, so you might have to cut a few corners. Your income, however, is probably the same if not slightly higher. This is, therefore, only a temporary situation, and your accounts should be back to normal in time, although some caution with regard to spending may need to be observed for a while. Work creatively on your budget and try to relax.