We have all been told that eight hours of sleep is the cornerstone of good health. It sits right alongside “drink two litres of water” and “walk 10,000 steps”, one of those golden rules we are supposed to follow if we want to feel our best.

And yet, everyone knows that one person. The friend who survives on five hours a night, bounces out of bed, and still seems to be running on all cylinders. It is easy to put it down to magic, or to assume they have simply been born with a superpower.

But strip away the myths and the folklore, and there is a real question left: is there an actual explanation? Is cutting your sleep to five or six hours genuinely risky? And, perhaps more interesting, can you train your body to adapt to less?

We hear it everywhere: get at least eight hours of sleep. But who decided that was the magic number? What if seven is perfectly fine for you? Or what if your body actually needs nine?

Surprisingly, the eight-hour rule didn't come from a scientist. It gained popularity in the 19th century, when social reformer Robert Owen proposed a simple formula: eight hours of work, eight hours of recreation and eight hours of rest. It was a call for better working conditions, not a scientific prescription for sleep.

But before you conclude that we have been following 200-year-old advice ever since, there is more to the story. Decades of research have explored how much sleep we actually need.

Take a well-known 2003 experiment in which 48 adults were allowed four, six or eight hours in bed each night for two weeks. Those in the eight-hour group maintained relatively stable cognitive performance, while the others showed a steady decline.

Then, in 2015, the National Sleep Foundation brought together 18 experts to review 312 scientific publications examining the relationship between sleep duration and health, from cardiovascular disease to cognitive performance. They assessed the evidence and developed recommendations for nine age groups. Their conclusion? Adults aged 18 to 64 should generally aim for seven to nine hours of sleep.

So eight hours isn't a myth, but it isn't a magic number either — just a comfortable middle ground. For some, seven might be enough. Personally, I would happily take a good nine.

We all know someone like that. They sleep half as much as the rest of us and somehow still have energy to spare. So what is going on? Are they simply better at handling exhaustion, or do some people genuinely need less sleep?

One of the most interesting answers comes from neuroscientist Ying-Hui Fu and her team at the University of California, San Francisco. In 2009, they studied a family in which two members regularly slept far less than their relatives — around five to six hours a night compared with the usual eight. No constant alarms, no desperate reliance on coffee. They simply woke up naturally after a short night, feeling rested.

The researchers discovered that both carried a rare variant of a gene called DEC2, involved in regulating sleep. To investigate further, the scientists introduced the same mutation into mice, which also began sleeping less. In other words, this wasn't necessarily a matter of discipline. Genetics appeared to play a role.

So how common are these lucky people? Nobody really knows. According to CDC figures published in April 2026, 30.5% of American adults sleep fewer than seven hours a night. But does that mean almost a third of us are natural short sleepers? Not even close. Sleeping less and actually needing less sleep are two very different things.

And how can you tell if you are one of them? There is no simple test you can just go and take. But there are a few clues: a lifelong pattern of short sleep, waking naturally without an alarm and feeling rested throughout the day. A sleep diary can help identify these patterns, although it cannot confirm the condition on its own.

But are these people actually healthy? So far, research suggests they are. However, long-term studies are still lacking, so we can't say for certain whether natural short sleepers face the same health risks associated with chronic sleep deprivation.

Now comes the question you were probably hoping I would get to: can you actually train your body to need less sleep?

Unfortunately, you can get used to sleeping less, but that doesn't mean your body has learnt to need less sleep. Research suggests that people who consistently sleep too little often underestimate how much their performance has deteriorated. In other words, you might feel perfectly fine while your attention and reaction times tell a different story.

But if you are determined to squeeze a few extra hours out of your day, there are a few tricks people swear by:

The catch? None of these tricks has been shown to reduce how much sleep your body actually needs. You might find ways to feel more awake, but that doesn't necessarily mean you are functioning any better. And there is a rather surprising reason for that.

This point has come up here and there throughout the article, but it is worth giving it a little more attention: the less you sleep, the less accurately you may judge how tired you actually are. And there is some fascinating research to back this up.

Let me guess: you know the feeling. You are up late writing an essay, finishing a report or drafting an important email. You are exhausted, but you keep going. Finally, it is done. You read it through one last time. Looks perfect. Brilliant. Off to bed. Then morning comes. You open it again, give it another read and... wait a minute. How did you think this was any good last night?

Well, science might have an explanation. When you are tired, your brain doesn't simply start making more mistakes — it may also become worse at noticing them. In 2011, researchers writing in Nature discovered that groups of neurons in sleep-deprived rats could briefly switch off, even while the animals were awake. These tiny lapses were linked to mistakes.

So that brilliant email you wrote at 2 am? You might have been too tired to realise it wasn't quite so brilliant after all.

At the end of this Tuesday wellness piece, I have a confession to make. During one of my therapy sessions, I admitted something to my psychologist: I envy my husband.

He wakes up at 5 am, goes for a two-hour cycle, comes home, gets ready for work, puts in a full day at the office and still has the energy for evening plans. Meanwhile, no matter how hard I try, I simply can't keep up. I can wake up earlier one day, but the rest of it will be a complete write-off. Even cutting an hour off my usual sleep leaves me exhausted and unable to function properly. I have had blood tests to check my iron and ferritin levels, and everything is where it should be. I have tried all the coffee in the world. Nothing helps.

My psychologist's response was rather straightforward: “You need as much rest as you need. Simple as that.” And she is right. My body demands eight, sometimes nine, hours of sleep, but it holds up its end of the bargain. In return, I get the energy for a proper workout and a brain that actually does its job.

So why am I telling you all this? Because after all the studies, experiments and genetic discoveries we have explored, my conclusion is rather simple: if you know your body needs eight hours of sleep, stop trying to negotiate it down to six. No clever hacks, no ambitious plans to become a 5 am person (unless you are happy to be in bed by 9 pm), and no convincing yourself that another coffee will do the trick.

Your battery has its own capacity. You can push it to its limits, but don't forget to charge it back up.