Reduced sleep isn't merely a symptom of mania, getting too little sleep can actually precipitate manic and hypomanic episodes. Research has revealed that up to 65 percent of bipolar patients who had a manic episode had experienced a disruption in their sleep routine prior to the episode.
Once when I was in a hypomanic-insomniac state, I painted the entire basement in a night. May sound productive, but my mania escalated and I became very dysfunctional, with racing thoughts, jitters, pressured speech (talking FAST) and severe irritability. It wasn't fun.