Uberman. The uberman sleep schedule is a way to get more waking hours out of a day without feeling tired. The concerns include lack of consolidation of sleep overall and changing your overall sleep architecture. When looking at the grand scheme, my primary concern is severe sleep deprivation, which has been shown to be fatal is mice studies. Need to be prepared to be tired & take about 2 weeks to start.
Potentially. The uberman sleep schedule is a method by which you retrain your sleep habits and patterns to maximize your rem sleep; the method attempts to retrain you to quickly enter the rem phase of sleep. However, your overall concentration and energy may drastically suffer. You should also be aware that there have been no long term studies regarding this so i would caution it's use at this time.