Dreams occur in the Rapid Eye Movement (REM) stage of sleep. We tend to remember the dreams that are seen just prior to waking up, but often the experience of time during our dream and awake stages is skewed.
Swedish and German scientists studied Lucid Dreamers(People who are aware while dreaming and are able to control the dream) and found out that there is a negligible time difference in non-physical tasks done in the dream stage vs in reality.

Physical tasks, like running, took longer in dreams than in reality.