Excellent article, however not 100% sold on the conclusion of needing a full 8 hours of sleep per night. There's long been controversial debates about the value, benefits and sustainability of biphasic or polyphasic sleep, considering that the majority of time spent sleeping during an 8 hour session is wasted stages with little known benefits.
If you are aware of any recent or definitive research on the topic I'd love to review them.
RE: How REM Sleep Cycles Affect your Mind and Body