Biphasic sleep refers to having two split sleep cycles, say from 11 to 3, and then from 6 to 10. This sounds like a strange way to get the sleep we need, but according to some sleep experts, this may be the way it's meant to be.
Were we designed to sleep in shifts? Some scientists, including Richard Stevens, an epidemiologist at the University of Connecticut, suggest this may well be the case. Before all the modern inventions, including electric lights, television and late night shopping, it may well have been natural to sleep in two distinct shifts with an hour - or more - break in the middle.
Sleep experts argue that this may well have been plausible years ago, but in this day and age, it's difficult to obtain the required seven to nine hours sleep that keeps our minds and bodies functioning properly.
Those hours of sleep give the body and mind a chance to recuperate from the stress and strain of the day. A good night's sleep strengthens the immune system and avoiding such debilitating conditions as diabetes and obesity.
Years ago, people hit the pillow earlier. They slept for a few hours, woke up and reflected on the day past or planned the day ahead, or, possibly just relaxed in the peace and silence of the darkness, then slept another four hours or so.
These days, if people awaken in the middle of the night, they toss and turn in an effort to get back to sleep, or get up and read or watch TV. Many become stressed worrying about not getting enough sleep, and, of course, the more stressed they become, the less liable they are to get back to sleep.
Researchers at the National Institute of Mental Health decided to test out this theory. Fifteen test subjects were asked to rest in the darkness between six in the evening and eight in the morning. At first, they slept up to eleven hours at a stretch. Then they began lying awake quietly for a few hours before falling asleep, or falling into what is called "biphasic sleep." This is the way of sleeping for a few hours, awakening to lie quietly for an hour a two and then falling back to sleep until morning.
During the awake time, researchers discovered that the test subjects secreted elevated amounts of the hormone prolactin. This is the hormone mothers excrete during breast-feeding that provides a state of calmness.
This two-phase method of sleep may be the way to go, if you can manage it without depriving yourself of the seven to nine hours of sleep the body needs. It may well explain one of the manifestations of insomnia, when a person awakes in the middle of the night and cannot get back to sleep.
Perhaps the answer is - go to bed earlier, and when you do awaken, don't stress, don't worry. Just lie there and enjoy the peace of the night.