If you’re constantly beating yourself up for not getting eight hours of sleep, we have news that might actually help you rest easier: that magic number everyone quotes? It’s not a universal rule. It’s an average. And averages, by definition, don’t apply to everyone.
Sleep experts are increasingly vocal about a truth that’s been buried under decades of blanket recommendations: some people genuinely need only five or six hours of sleep, while others require nine or ten. Your biology determines your sleep needs just as much as it determines your height or metabolism. The key is figuring out what YOUR number actually is — and no, it’s not necessarily eight.
Quality Over Quantity (Finally)
Dr. Tony Cunningham, a clinical psychologist and director of the Center for Sleep and Cognition in Boston, argues that most people obsess over hours while completely ignoring sleep quality. “There are two different things going on in our bodies that dictate both the type of sleep and quality of sleep we’re getting,” he explains: sleep pressure and circadian rhythms.
Sleep pressure builds the longer you’re awake, like hunger increasing the longer it’s been since you’ve eaten. Your circadian rhythm is your body’s internal clock, sending either sleep-promoting or wake-promoting signals throughout the day. For quality sleep, these two systems need to work together.
This is why going to bed at wildly different times wrecks you even if you’re technically getting “enough” hours. Your body thrives on consistency, not on hitting an arbitrary number. Waking up at the same time every day turns out to be more impactful than going to bed at the same time — because forcing yourself into bed when you’re not actually sleepy just means you’ll lie there building frustration instead of sleep pressure.
The Eight-Hour Lie We All Believed
The standard advice to get seven to nine hours comes from population averages. Studies show most adults function best within that range, and sleeping significantly less increases risks for obesity, high blood pressure, heart disease, and other chronic conditions. Fair enough.
But here’s what gets lost: “That does not mean every single person on the planet needs eight hours of sleep,” says Cunningham. Some people’s biology and physiology truly only require five or six hours for optimal functioning. Others genuinely need nine, ten, or even eleven hours. Telling everyone to aim for eight is like telling everyone to wear size nine shoes because that’s the average.
Recent research backs this up. A study published in the Proceedings of the National Academy of Sciences found that optimal sleep duration varies significantly between cultures, and people whose sleep aligns with their cultural norms enjoy better health outcomes regardless of the specific number of hours. Your sleep needs are shaped by genetics, behavior, medical factors, and environment — not by what works for most people.
Finding Your Magic Number (It Takes Work)
So how do you figure out your actual sleep requirement? Cunningham offers a method that sounds simple but requires commitment and ideal circumstances.
First, pick a consistent bedtime when you’re genuinely sleepy — not just tired, but actually ready to fall asleep within 20 to 30 minutes. If you get into bed and can’t fall asleep in that window, you haven’t built up enough sleep pressure yet. Get back up and do low-arousing activities with dimmed lights until you feel properly sleepy.
Then comes the challenging part: you need a period when you can sleep with no alarm until you wake naturally. Hide your clocks, block out light with blackout curtains, use white noise machines, wear an eye mask — eliminate any external cues about what time it is. Go to sleep at your consistent bedtime and let your body wake itself up.
“The first couple of days, you’re probably going to sleep for longer than you normally would,” warns Cunningham, as your body catches up on accumulated sleep debt. If you go to bed at midnight, don’t be surprised if you sleep until 10 or 11 a.m. initially.
After that catch-up phase, you’ve found your true sleep duration “when you wake up for three or four days in a row at approximately the same time with no external cues, no light cues, and no alarm.” Calculate the hours between your bedtime and natural wake time. That’s your number.
When “Good Sleep Hygiene” Isn’t Enough
Of course, not everyone can execute this experiment. You need flexibility — maybe you’re home for the holidays, between jobs, or on an extended vacation. But if sleep has been a persistent concern and you have the opportunity, it’s worth discovering whether you’ve been chasing the wrong target all along.
The National Sleep Foundation’s 2025 poll found that six out of ten American adults don’t get enough sleep, and nearly half struggle to stay asleep multiple nights per week. But “enough” is the operative word here. For some of those struggling sleepers, the problem might not be duration at all — it could be quality, consistency, or simply aiming for a number that doesn’t match their biology.
There’s also the cultural dimension. Research comparing sleep across countries reveals that people in cultures with shorter average sleep durations don’t necessarily suffer worse health outcomes. The optimal amount varies by culture, and people closer to their cultural sleep norms fare better. This suggests sleep needs are more flexible and socially shaped than we’ve acknowledged.
Stop Feeling Guilty About Your Sleep
The biggest takeaway? If you consistently wake up feeling rested after six hours and function well throughout the day, you’re not broken — you’re just not average. And if you need nine hours to feel human, that’s not laziness; it’s biology.
The seven-to-nine-hour recommendation isn’t wrong — it works for most people. But treating it as a universal law ignores individual variation and can actually create sleep anxiety. People lie awake stressing about not getting eight hours, which ironically makes sleep worse.
Focus instead on sleep quality: consistent wake times, building proper sleep pressure before bed, and aligning your schedule with your circadian rhythm. Once you’ve optimized those factors, let your body tell you how much sleep it actually needs. The answer might surprise you — and it probably won’t be exactly eight hours.