Most of us, in the modern “Western” world at least, have monophasic sleep patterns. This simply means that we go to sleep once within the 24 hours that make up a day.
There is debate as to whether this is really the most appropriate way for our bodies to take sleep. For example, we know that most people experience a daytime drop in alertness and awakeness, sometime in the afternoon between 1pm and 3pm. Personally, I’m utterly useless around 2.30pm most days. Some cultures have a tradition of napping during this peak time for sleep, whereas in others it is more usual to knock back some coffee and power through until the evening, despite a growing consensus that napping is incredibly beneficial, for our health and well-being, and for things valued by certain strata of Western society, like productivity and creativity.
There are a number of other ways that we could be sleeping, such as biphasic sleep, and there are, naturally, differences between individuals in how much sleep is required, when in the 24 hour cycle this is best acquired, and whether mono- or biphasic sleep is preferable. In fact there are even some individuals whose sleep-wake cycle is completely out of whack with the rotation of the earth, and operate instead on 25 or more hour cycles. This is has been called “non-24-hour sleep-wake disorder”. Those who have this disorder may really struggle to cope with the demands of modern society, because their biological rhythms will not allow them to adapt to the standard clock. Unfortunately, because most people are expected to live by the 9-5 (or similar) working day, most people don’t get the chance to figure out what’s best for them. Everyone should have the right to proper sleep, but sadly it is a luxury for many. One sleep scientist in the UK has even likened the constant sleep deprivation that many workers endure due to working hours as being akin to torture.
There have also been attempts to design methods of being able to function with many fewer hours of sleep than most people need (in the neighbourhood of 7 hours), such as having several short (20-30 minute) naps across the 24 cycle. I am generally an open-minded kind of person, but my personal take on this is one of extreme scepticism. I really don’t recommend trying this. It sounds to me like a solution to a problem that shouldn’t exist, i.e. needing more hours in the day to be more productive and/or active. We are already incredibly active at night during sleep (in terms of brain activity), in ways that have been demonstrated over and over again to be crucial for a healthy and happy body and mind. In my opinion, we should be looking at ways of finding more hours for sleep, not more hours for being awake.