Most adults cannot healthily sleep less than seven hours a night. The American Academy of Sleep Medicine and Sleep Research Society are clear: six or fewer hours is inadequate to sustain health and safety. But if you’re searching for ways to sleep less, the practical answer isn’t about cutting hours. It’s about eliminating wasted time in bed so every hour of sleep actually counts.
Why Your Brain Can’t Truly Adapt to Less Sleep
One of the most persistent beliefs about sleep is that you can train yourself to need less of it. Research tells a different story. When people are chronically sleep-restricted, they stop feeling as sleepy over time, which creates the illusion of adaptation. But cognitive testing shows their performance continues to decline even as their subjective sense of tiredness levels off. In other words, you get used to feeling impaired without realizing you’re impaired.
A study tracking nearly 8,000 people over 25 years found that those who consistently slept six hours or less per night from their 50s onward were 30 percent more likely to develop dementia compared to those who slept seven hours. Chronic sleep restriction also triggers glucose intolerance, insulin resistance, and low-grade inflammation, even in people who aren’t overweight. These aren’t dramatic, immediate consequences. They accumulate quietly over years, which is exactly what makes them dangerous.
The Rare Exception: Natural Short Sleepers
A small number of people genuinely need less sleep due to specific genetic mutations. Researchers have identified four genes (DEC2, NPSR1, mGluR1, and a mutation in the gene controlling a specific stress-response receptor) that allow some individuals to function fully on four to six hours. These people don’t force themselves to sleep less. They simply wake up naturally and feel rested.
The prevalence of natural short sleepers is extremely rare, and studies on this population remain limited. If you’ve always needed an alarm to wake up, feel groggy in the morning, or rely on caffeine to get through the afternoon, you almost certainly aren’t one of them.
Sleep Quality Matters More Than Sleep Quantity
Here’s where the real opportunity lies. Research increasingly shows that sleep quality is a better predictor of health and daytime functioning than sleep quantity alone. Restfulness, the absence of daytime sleepiness, and sufficient deep sleep matter more than raw hours. Two people can sleep seven hours and have completely different outcomes depending on how much of that time is spent in restorative deep sleep versus light, fragmented sleep.
A typical night of good sleep follows a predictable pattern: more deep sleep in the first third of the night, with REM sleep and lighter stages increasing toward morning. When this architecture is disrupted by noise, alcohol, screen light, or an inconsistent schedule, you can spend eight hours in bed and still wake up feeling like you need more. Improving the quality of your sleep won’t let you sleep four hours, but it can make seven hours feel like a full recovery instead of barely enough.
How to Spend Less Time in Bed
Many people who want to “sleep less” are actually spending more time in bed than they need to, lying awake before falling asleep or hitting snooze repeatedly in the morning. Tightening your sleep window so it matches your actual sleep need is the safest way to reclaim time.
Start by tracking how long you actually sleep versus how long you’re in bed. If you’re in bed for nine hours but only sleeping seven, you have two hours of wasted time. Gradually move your bedtime later (or wake time earlier) in 15-minute increments until you’re spending close to seven hours in bed and sleeping through most of it. This approach, sometimes called sleep restriction in clinical settings, increases what researchers call sleep efficiency: the percentage of time in bed that you’re actually asleep.
Reduce the Time It Takes to Fall Asleep
If it takes you 30 to 45 minutes to fall asleep, environmental changes can cut that significantly. Your bedroom should be very dark, not just dim. Block light from windows with room-darkening shades, cover the light from clocks and chargers, and prevent light from entering under doors. Remove or block sources of white or blue light, including phones and televisions.
Temperature matters too. A cool room helps your core body temperature drop, which is a biological signal for sleep onset. Keep the room comfortable and slightly cool rather than warm. These aren’t minor tweaks. For people with a long sleep onset, darkness and temperature alone can save 20 to 30 minutes a night, which adds up to over two hours a week of reclaimed time.
Strategic Napping as a Tool
If your goal is to shorten your main sleep block, a well-timed nap can partially compensate. Naps of 15 to 20 minutes increase alertness for a couple of hours afterward, with minimal grogginess on waking. The key is waking before you enter deeper sleep stages, which typically begins around the 20-minute mark. Set an alarm for 20 minutes and stick to it.
Longer naps of about 90 minutes allow you to complete a full sleep cycle and wake from a lighter stage, which also reduces grogginess. But a 90-minute daytime nap will reduce your sleep pressure at night, making it harder to fall asleep. For most people on a daytime schedule, the brief nap is the better option.
What About Polyphasic Sleep?
Polyphasic sleep schedules, which break sleep into multiple short blocks throughout the day, have a devoted online following. The Everyman schedule involves a three-hour core sleep at night plus three 20-minute naps during the day, totaling about four hours. The Uberman schedule is more extreme: six 30-minute naps spaced every four hours, totaling two to three hours of sleep per day.
Cleveland Clinic’s assessment is blunt: the risks likely outweigh the rewards. These schedules don’t provide enough time for the full cycles of deep sleep and REM sleep your brain requires. They’re also nearly impossible to maintain alongside a normal work or social life, since missing a single nap window can leave you severely impaired. Most people who attempt them abandon the schedule within weeks.
Supplements for Deeper Sleep
If your sleep feels unrefreshing despite adequate hours, certain supplements show modest benefits for sleep quality. Magnesium supports the brain’s main calming neurotransmitter system, reducing neuronal excitability and promoting relaxation. A recent randomized trial found that 250 mg of elemental magnesium (taken as magnesium bisglycinate) daily reduced insomnia severity scores compared to placebo within four weeks. The effect was statistically significant but modest.
Glycine, an amino acid that also acts as a calming neurotransmitter, may promote deeper sleep by lowering core body temperature. Some studies suggest 3 grams before bed can improve sleep quality and reduce next-day fatigue. Magnesium bisglycinate conveniently contains both compounds, though the glycine dose in typical magnesium supplements (around 1.5 grams) is lower than what’s been studied independently.
The Realistic Goal
The honest answer to “how to sleep less” is that you probably can’t go below seven hours without paying a price, even if you don’t feel it. What you can do is make those seven hours more efficient: fall asleep faster, wake up less during the night, spend more time in deep sleep, and stop lying in bed awake. For most people, optimizing sleep quality and tightening the sleep window can free up 30 to 90 minutes a day. That’s 3.5 to 10 extra hours a week, gained without the cognitive decline, metabolic disruption, and long-term disease risk that come with actual sleep deprivation.