If you struggle to wake up feeling well-rested, despite having plenty of kip, your bedtime is likely the problem.
That’s according to Dr Charles Puza, who told his 811,000 Instagram followers that the time you go to bed is key for ensuring you complete all of the vital stages of sleep.
In a video clip, the ‘biohacker’ and dermatologist who studied at Harvard and Duke universities, revealed a simple formula to compute your ‘perfect’ bedtime, that will ensure you get through the maximum number of sleep cycles.
Cycles are made up of four stages of sleep, which get gradually deeper. The fourth, and most crucial, stage of sleep is known as repetitive eye movement sleep (REM).
REM is the type of sleep that is essential for emotional processing and cognitive functioning, and is the part of the sleep cycle in which you’re most likely to dream.
Each sleep cycle is around 90 minutes — but if it is disrupted by a buzzing alarm clock right in the middle, you may miss out on the most restorative phase.
The ideal wake-up time, experts say, is at the end of a full cycle, or at the very beginning of a new one.
A healthy adult needs around seven to nine hours of sleep a night, according to NHS advice.
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Dr Charles Puza (pictured) explained that timing what time you nod off with natural sleep cycles can help you feel refreshed. During sleep the brain goes through four natural stages of activity non-REM sleep and REM sleep
That means a person goes through roughly five or six cycles a night.
Dr Puza says the first step in calculating your perfect bedtime is deciding on either five or six sleep cycles — depending on what’s realistic.
He then suggests adding 15 minutes on to allow yourself time to fall asleep.
‘So, if you want five cycles that’s seven hours and 45 minutes and six cycles is nine hours and 15 minutes.
‘Say you have to be up for work at 7am simply subtract whether that’s a five cycle or six cycle night, define your ideal bedtime of either 9.45 or 11.15pm.’
However, judging by comments on the video, the most pressing problem is being able to fall asleep in the first place.
‘I can lay in bed for hours before I finally fall asleep, no matter how tired I am. Falling asleep in 15 minutes would be a miracle,’ one Instagram user said.
Another admitted they were watching the video at 4am as they struggled to get back to sleep.
Dr Puza said he is ‘obsessed’ with making sure he gets the ‘best sleep possible’, adding that a good night’s rest is essential for anti-ageing, muscle recovery, memory and brain health.
One in three adults in the UK and almost half of US adults suffer with insomnia, with millions more reporting sleepless nights.
Consistently failing to get enough shut eye raises the risk of obesity, heart disease and type 2 diabetes, swathes of research shows.
Insomnia can be caused by stress, anxiety, alcohol, caffeine or nicotine, noise, shift work and jet lag.
If you regularly have problems sleeping, there are simple ways to improve your sleep hygiene.
This includes keeping regular sleeping hours, staying active in the day and by creating a restful quiet space to sleep.