The idea is to align your bedtime to your 90 minute sleep cycles, so you wake after a complete cycle in REM sleep (when we have structured dreams) and thus feel more refreshed.
Our sleep cycles are made up of different stages, and it's crucial to complete a full cycle for optimal muscle gains and recovery, and mental rejuvenation and well-being. And cycles of 90 minutes of sleep seem to be the perfect amount of time to complete a full sleep cycle.
It consists of setting two alarms, one at the time you should wake up and another 90 minutes before. So to wake up energetically at 8:00 a.m., you set an alarm at that time and another at 6:30 a.m. That way, you make sure you have a full sleep cycle before waking up.
Splitting sleep significantly enhanced afternoon picture encoding and factual knowledge under both 6.5 h and 8 h durations. Splitting sleep also significantly reduced slow-wave energy during nocturnal sleep, suggesting lower homeostatic sleep pressure during the day.
Sleeping beyond the 90-minute cycle may mean you fall deeper into your sleep cycle and will find it much harder to wake up. The best answer to this question is that some sleep is always better than none. Trying to get in a power nap or achieving that full 90-minute cycle is better for you than no sleep at all.
The main theory behind why the snooze period was set to nine minutes is a technical one. The snooze function had to be worked in around the existing gearing of a small alarm clock, and keeping the time period in single digits is said to have presented a more logical technical solution.
It's possible that when you're especially tired, your body's need for sleep overrides its biological clock, he explained. Or sometimes, if you feel nervous about waking up on time, stress may cause you to wake up earlier than you'd like, Dr. Allada said.
Hitting snooze only once is less harmful to your sleep health than doing so again and again. Try to limit the extra relaxation time to nine minutes rather than 18 or 24. The more times you put off getting out of bed, the more you confuse your brain and risk sleep inertia.
Many experts recommend the 2-3-4 approach for babies needing two daytime snoozes. It works by gradually increasing the time between naps throughout the day: two hours of staying awake before the first nap, three hours between the first and second naps, and four hours before bedtime.
Ferber aka Controlled Crying or Check and Console Method
On the first night, the parent visits after 3 minutes, then 5 minutes, then every 10 minutes until the child is asleep. Each night thereafter, the intervals between visits get longer.
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).
Take the time you plan to wake up (say, 6 a.m.) and subtract the recommended 7 to 9 hours of sleep (which is around 9 to 11 p.m. the night before). This is your bedtime ballpark.
If you wake up early feeling alert, should you just get up? It depends how early it is. If it is 3am, you should do your best to get back to sleep because if you don't, you're likely to feel tired and irritable later.
“It becomes kind of like jet lag,” says Dr. Winter. “You wake up feeling kind of groggy, like you have a dull headache, maybe a bit of nausea, and lethargy—you just don't feel like doing anything.” Your best bet is to resist the urge to nod back off after you wake up.
Alarm clocks did exist before the snooze function, so there was already a standard gear setup that innovators had to work with. Getting the gear teeth to line up to allow for exactly ten minutes wasn't possible, so they had to choose between setting it at nine minutes and a few seconds or a little bit over ten minutes.
When the snooze feature was added to alarm clocks years ago, it was done so by retrofitting the new snooze component in the design of an existing clock. As Apple Explained says, "This was a problem, since they [alarm clock makers] couldn't adjust the clock's gear teeth to line up perfectly for a ten-minute snooze.
The nine-minute snooze has remained the default snooze time on alarm clocks since then, and wanting to pay homage to that tradition, Apple also chose to use it for the iPhone's alarm.
Now, he makes an effort to sleep at least six hours per night, he said in an interview with CNBC's David Faber on Tuesday. “I've tried [to sleep] less, but ... even though I'm awake more hours, I get less done,” Musk said. “And the brain pain level is bad if I get less than six hours [of sleep per night].”
“A midday nap is helpful at any age to help boost cognitive activity,” says Dr. Roehrs. “But since memory problems are often a natural function of aging, a midday nap is even more beneficial for older adults.”