But the notion that we need all of our sleep in one unbroken block, is not necessarily driven by our biology. And there's a good deal of evidence to show we haven't always had this approach to sleep.
In Geoffrey Chaucer's 14th century text, The Squire's Tale, the king's daughter, Canacee, is described as having a "fyrste sleep," arising in the early morning ahead of her companions, who sleep fully through the night.
And in 15th century medical texts, readers were advised to lie on their right side during a "first sleep" – and the left side for a "second sleep", so as to aid digestion.
Indeed, references to a first and second sleep are littered throughout Western history and literature.
Sleep historian Roger Ekirch of Virginia Tech uncovered numerous references to segmented sleep as he trawled back through centuries of writing.
"Western Europeans … referred to both intervals [of sleep] as if the prospect of awakening in the middle of the night was utterly familiar to contemporaries and thus required no elaboration," Professor Ekirch wrote in his 2001 research.
He suggested going to bed when the sun went down, waking in the middle of the night for a couple of hours, then sleeping again until sunrise was a normal way of being – perhaps even the most common sleeping pattern.
When people woke in the middle of the night they would do all kinds of things — housework, have sex, pray, socialise or reflect on their dreams — and then return to their second slumber.
But something changed around the time of the Industrial Revolution. Electric lighting became more common, and with that references to a "second sleep" began to disappear.
"Once we could confine ourselves comfortably indoors at any time, we saw the gradual breakdown of our sleeping patterns to conform to what our new needs were," Flinders University Emeritus Professor Leon Lack said.
Most people in the Western world gradually adopted this "monophasic," or single block, of sleep — in contrast to the biphasic, segmented sleep that had been the norm.
But evidence suggests humans tend towards the biphasic sleep if given the opportunity.
Back in the 1990s, psychiatrist Thomas Wehr showed when people were exposed to 14 hours of darkness, not eight, they gradually moved to a biphasic sleep pattern — two four-hour blocks with a gap in between.
Of course, sleeping patterns and behaviours vary between cultures, and the history above applies primarily to Europe. You can still find two-stage sleep patterns in many cultures, in Spain for example, where businesses still close in the afternoon for siesta in some parts of the country.
Sleeping in a single block is considered the healthy norm, but problems arise when you have an expectation it'll always be a perfect eight-hour span of blissful nothingness, Professor Lack said.
Many of us tend to think healthy sleep is a deep valley of unconsciousness across the entire period you're in bed, but the reality is more complex.
"When we ask people to draw a graph across time … 70 or 80 per cent of them draw this long U-shaped curve that descends into a deeper sleep that lasts four or five hours, before emerging into lighter sleep."
"It's generally held that this is normal sleep, and that's what it should look like. And that's totally incorrect."
Rather, we cycle through periods of light and deep sleep every 90 minutes or so.
There are natural periods of wakefulness in this "rollercoaster" sleep cycle.
"Awakenings occur as part of a healthy sleeping pattern," Professor Lack said.
Thus it's our expectations around how we should sleep — and the actual reality of it — that cause some people anxiety and insomnia, he said.
"People worry about these awakenings and once they start worrying, the awakenings become longer, and you can have the development of insomnia."
Dr Siobhan Banks from the Sleep Health Foundation said the most important thing is to get enough sleep, and to get it during your natural circadian low after the sun sets if possible.
"Sleep isn't only one kind of way," she said.
"As long as you're getting an okay sleep, even if it's broken sleep, if you're getting a reasonable amount every 24 hours things are okay."
Sleep needs and ageing
This anxiety over awakenings is exacerbated with age, Professor Lack said, and that's because they become more frequent as we get older.
Our sleep needs generally decline over time — and when older people retire they may find more time for sleep and experience more awakenings from sleep, Professor Lack said.
"They might go to the doctor and say, 'Gee doc, I'm waking up two or three times a night and this really concerns me'," Professor Lack said.
"And the doctor doesn't really have many tools available to them, except to prescribe a hypnotic drug."
Instead, Professor Lack said he tried to get patients to consider the awakenings as normal and, "not something that will impair them during the next day".
Others still are interested in divvying up their sleep further — splitting it into a "polyphasic" model where they get by on naps alone, or a short "core sleep" of a few hours supplemented with naps.
Professor Lack said there was limited research into such sleep models, but the critical thing was that you got the required amount of sleep for your age.
And he said those who tried to fit parts of their sleep into the daytime might experience difficulty.
"Sleep is at its best quality when placed across the night time when our body clock is in its circadian low," he said.
Dr Banks said unless you were an "extremely unusual" person, a polyphasic sleep model wasn't going to work for you.
"People can stay awake quite well over several days and function normally … but if they are left alone for any significant period of time sitting still, they'll fall asleep," she said.
"After a couple of days it all falls apart."