Our ancestor’s sleep was driven by the day/night cycle, which shaped their circadian rhythm, but we can disrupt that with the flick of a switch.
Prehistoric man had biphasic sleep maybe about two phases of four hours sleep separated by a period of wakefulness when they may tend the fire, eat, or socialize. Other more modern nationalities have a biphasic pattern with a longer sleep duration at night and a nap during the day coinciding with the lull we often experience as the early afternoon slump in wakefulness.
Today we are encouraged to sleep about eight hours and to achieve that monophasic pattern can be beneficial and convenient.
If however we experience a period of wakefulness after four hours this insomnia is usually considered a bad thing and that you are abnormal.
Maybe this biphasic pattern is a problem in our society today because of the stress we constantly experience during the day or when we wake at night.
Lying awake with no distractions we allow a lot of negative thoughts to invade our mind and have difficulty returning to sleep even though this pattern may have been ingrained for centuries.
Mindfulness and meditation can be helpful can be helpful in allowing us to get back to sleep and have a quality bout of sleep for the rest of the night.
What you do prior to sleep, your pre sleep routine, will set you up for a quality nights sleep even if it is biphasic.
Biphasic sleep has been with us for thousands of years and therefore if recognised and handled in an appropriate way should not be just another stress we have to cope with.