However, as NREM 2 gets reduced, the ability to stay awake for long periods diminishes. This is why schedules with less total sleep time (TST) need more sleeps spread throughout the day to be sustainable. Taking a ~20-minute nap or a ~90-minute single-cycle core helps a polyphasic sleeper sustain wakefulness. Maximum wake gaps are dependent on the schedule, time of day, as well as the sleeper's individual needs. With gaps too large, one will always experiences bouts of tiredness during it and be unable to fully adapt to the schedule.
然而，隨著NREM2的減少，長時間保持清醒的能力也會減弱。因此，總睡眠時間（TST）較短的時程需要有更多睡眠段落分佈在一天中。約20分鐘的小睡或約90分鐘的單周期主段有助於多相睡眠者維持清醒狀態。最大的覺醒間隔取決於你所選的時程、日程安排以及睡眠者的個人需求。如果間隔太大，你在這期間將會總是感到陣陣疲憊，進而無法完全適應時間表。
