Sleeping in parts, known as segmented or biphasic sleep, can work for some people, especially with a midday nap, potentially boosting alertness and cognition, but for many, it disrupts natural sleep cycles, leading to less restorative sleep, grogginess, and potential health issues like sleep deprivation, so it's crucial to see how your body responds and consult a doctor if you experience fatigue.
There are mixed views on whether segmented sleeping is safe. Since there hasn't been much research on the effect sleeping in shifts can have on your health, it's best to avoid it unless there's a reason you need to sleep that way, says Clete Kushida, MD, PhD, the medical director of the Stanford Sleep Medicine Center.
Is it OK to sleep 4 hours twice a day? Sleeping four hours twice a day is a form of biphasic sleep. This pattern splits your sleep into two equal parts. It might be suitable for those who naturally wake up in the middle of the night or those who find it challenging to get a continuous eight hours of sleep at night.
You can sleep for six hours and take a nap, but sleeping for longer at night is better as sleep works best when it's uninterrupted. However, if you can't get enough sleep at night, sleeping for six hours and taking a nap can help you catch up on lost sleep and boost your energy levels.
With total sleep opportunity at 8 h—the minimum recommended, we found that a split sleep schedule with 6.5-h nocturnal sleep and a 1.5-h nap achieved similar performance in basic cognitive tasks, subjective alertness, and mood as the nocturnal sleep only schedule.
The 10-3-2-1-0 rule is a popular sleep hygiene guideline that creates a countdown for winding down before bed, advising: 10 hours without caffeine, 3 hours without big meals or alcohol, 2 hours without work or stressful activities, 1 hour without screens (phones, TV, computers), and aiming for 0 snoozes in the morning, promoting better sleep quality by reducing stimulants and preparing the body and mind for rest.
Einstein slept nearly 10 hours a day. He was known to be a firm believer in the importance of a good night's sleep, often aiming for around 10 hours of rest. However, his approach to sleep was somewhat unconventional.
The koala is the animal that sleeps approximately 90% of the day (20-22 hours), a necessity due to its low-energy eucalyptus diet requiring intensive digestion, making it the ultimate champion of sleep in the animal kingdom, followed closely by sloths and bats.
On the legitimacy of the 8-minute nap, he says “sleeping with your legs elevated can help improve sleep onset and quality as it allows blood to flow more easily throughout the body. This is the sleep science behind the 8-minute Navy Seal nap, but that's not the only thing that makes this nap potentially effective.”
Signs of poor core sleep (deep, restorative sleep) include waking up foggy, daytime fatigue/energy crashes, poor concentration, irritability, frequent illness, memory issues, and mood swings, indicating your brain and body aren't fully repairing and consolidating memories. You might also experience increased sugar cravings, slow muscle recovery, and a weakened immune system.
Musk goes to bed around 3 a.m. and gets about 6 hours of sleep every night. Although he's not getting eight hours a night, Musk has upped his sleeping schedule from being nearly nonexistent in the past. In May 2023, Musk told CNBC that he's no longer pulling all-nighters.
Yes, the Navy SEAL sleep trick (an 8-minute power nap with elevated legs) is a real technique for quick rest, popularized by former SEAL Jocko Willink, that helps improve alertness and reduce fatigue, though its effectiveness depends on individual relaxation skills and it's not a substitute for full nighttime sleep. The method involves lying down, elevating your feet above your heart (on a chair or couch), relaxing facial muscles, dropping shoulders, and clearing your mind for about 8-10 minutes to promote relaxation and blood flow, preventing grogginess.
Historian A. Roger Ekirch has argued that before the Industrial Revolution, interrupted sleep was dominant in Western civilization. Ekirch asserts that the intervening period of wakefulness was used to pray and reflect, and to interpret dreams, which were more vivid at that hour than upon waking in the morning.
The unhealthiest sleeping position is generally considered to be sleeping on your stomach (prone position), as it forces your neck to twist and flattens the natural curve of your spine, leading to neck, back, and shoulder pain, numbness, and poor sleep quality. An overly curled fetal position is also harmful, causing joint stiffness and restricted breathing, while sleeping on your back can worsen snoring and sleep apnea for some individuals.
People who regularly experience broken sleep are crankier, angrier, and more likely to be depressed than those who sleep through the night. In fact, a night of interrupted sleep is much worse for your mood than a shorter night's sleep.
Leonardo da Vinci
He followed a polyphasic sleep pattern with a 20-minute nap every four hours. Given his expertise in so many things -- invention, painting, sculpting, architecture, science, music and more – the unconventional schedule must have worked for him.
A prime example is the box breathing technique, famously used by the Navy Seals, known as the 4-4-4-4 method. This simple yet effective method involves a cycle of inhaling for 4 seconds, holding the breath for 4 seconds, exhaling for 4 seconds, and then pausing for 4 seconds before the next inhalation.
10 hours before bed: No more caffeine. 3 hours before bed: No more food or alcohol. 2 hours before bed: No more work. 1 hour before bed: No more screen time (shut off all phones, TVs and computers).
A powerful mindset to carry is the Navy SEALs 40% Rule: When your mind says you're done, you're only actuallly about 40% done. Physical injuries aside, our bodies are often far stronger than we think - the mind usually quits first, acting as a protective barrier rather than reflecting true limits.
Among the most rested countries surveyed by Sleep Cycle, an app that tracks how much shuteye people are getting, New Zealand comes top with the average Kiwi clocking up in excess of 7.5 hours per night. Finland, the Netherlands, Australia, the UK and Belgium all rank highly for sleep, too, with Ireland close behind.
The answer is “probably.” Research has shown that many animals experience a sleep phase similar to humans known as REM (Rapid Eye Movement) sleep, which is closely associated with dreaming. This phase is characterized by increased brain activity and is when most vivid dreams occur.
Because they are high achievers, they're often able to take on more than most. Even so, they eventually find their breaking point, and must start looking for a new solution to the problem of their limited time. Rather than scaling back commitments, high achievers double down and work even harder by sacrificing sleep.
The 30th president of the United States would often sleep up to 11 hours a day, including his two-to-four-hour afternoon naps.
Albert Einstein is said to have slept 10 hours per night, plus regular daytime naps. Other great achievers, inventors, and thinkers – such as Nikola Tesla, Thomas Jefferson, Thomas Edison, Winston Churchill, Leonardo da Vinci, and Sir Isaac Newton – are said to have slept between two and four hours per day.