The human body is typically asleep during the nighttime hours, primarily between 11 p.m. and 7 a.m. for most adults. This cycle is regulated by the body's internal biological clock, known as the circadian rhythm, which responds to light and dark cues.
If your school or work schedule requires you or your child to be up between 5:00 and 7:00 a.m., these are the suggested bedtimes: School-age children should go to bed between 8:00 and 9:00 p.m. Teens should try to go to bed between 9:00 and 10:00 p.m. Adults should try to go to sleep between 10:00 and 11:00 p.m.
Typically, most adults feel the sleepiest between 2 a.m. and 4 a.m., and also between 1 p.m. and 3 p.m. Getting plenty of regular sleep each night can help to balance out these sleepy lows. Your body's internal clock is controlled by an area of the brain called the SCN (suprachiasmatic nucleus).
The BHF verdict
Regina Giblin, Senior Cardiac Nurse at the British Heart Foundation, said: “This large study suggests that going to sleep between 10 and 11pm could be the sweet spot for most people to keep their heart healthy long-term.
The idea is that you'll have gradually increasing wake times between naps, with two hours before the first, three hours after that, and four hours just before bedtime. It's designed for babies who can do with just two naps a day, a stage that usually occurs between six and 18 months old.
The koala is famous for sleeping around 20-22 hours a day, which is about 90% of the day, due to their low-energy diet of eucalyptus leaves that requires extensive digestion. Other extremely sleepy animals include the sloth (up to 20 hours) and the brown bat (around 20 hours), with some snakes like the ball python also sleeping up to 23 hours daily.
The 3-2-1 bedtime method is a simple sleep hygiene strategy: stop eating 3 hours before bed, stop working 2 hours before bed, and stop using screens (phones, tablets, TVs) 1 hour before sleep, helping your body transition to rest by reducing stimulants and digestive load for better sleep quality. A more detailed version adds 10 hours (no caffeine) and 0 (no snoozing) for a 10-3-2-1-0 rule.
The "3-2-1 Bedroom Method" (or a variation like the 10-3-2-1 rule) is a sleep hygiene strategy to improve rest by staggering when you stop certain activities before bed: stop heavy food/alcohol 3 hours before, stop work/mental stress 2 hours before, and turn off screens (phones, TVs, computers) 1 hour before sleep, creating a better wind-down for your body.
The four Ps are problem solving, planning, prioritising and pacing. The aim is to think of the four Ps at the beginning of each day or week to help you manage your energy levels.
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.
Gen Z stays up late due to a combination of technology (blue light, endless content), significant stress and anxiety (FOMO, financial/global worries), biological shifts (natural teenage circadian rhythm), and "revenge bedtime procrastination," where they sacrifice sleep for personal time, often in bed, scrolling social media. This digital-heavy, high-stress lifestyle creates overstimulation and a misalignment with natural sleep patterns, leading to chronic sleep deprivation, notes the American Academy of Sleep Medicine and the Sleep Health Foundation.
In fact, the participants slept an hour longer in December than in June. Their rapid eye movement (REM) sleep, which is the most active stage of sleep when we dream and our heart rate increases, was 30 minutes longer in the winter than during the summer.
The 80/20 Rule means that you stick to your healthy, consistent sleep schedule 80% of the time. You then can make exceptions to your schedule 20% of the time. The 80/20 Rule allows you to “live life” and enjoy those special moments with your family.
Cortisol levels naturally start to rise in the body around 2-3 a.m. In people with typical cortisol patterns, this increase is gradual, gently helping them wake up at their usual time in the morning.
For most healthy adults, guidelines suggest at least seven hours of slumber. But these are general recommendations and not strict rules. "Some people need less than seven hours, while others might need more," says Eric Zhou with the Division of Sleep Medicine at Harvard Medical School.
In his piece, he revealed that through his years of research, he's found that rumination is the biggest thing that causes poor sleep. He says that being worried about something at night has affected his own ability to fall asleep.
You want to be facing (but not directly facing) the door, not have it opening along the same wall as your head, and according to Suzanne not beneath a window either. 'Locate the bed on a solid wall and always factor in a tall, comfortable headboard,' she continues.
To 100% fall asleep, combine a consistent schedule, a cool, dark room, and a wind-down routine (no screens, relaxing activities like deep breathing or hot baths) to calm your mind and body, using techniques like the 4-7-8 breath or military method if you're still awake, and get up to do something boring if you can't sleep after 15 minutes to break the anxiety cycle.
My personal routine is get ready for bed at 10pm (I sleep a lot so this can seem quite early), which involves: *taking meds *brushing teeth *unplugging everything in the house *Tidying room *preparing bags for the next day (although this could be part of a morning routine too) *getting into pyjamas *hanging clothes up ...
Our circadian rhythm functions by light and dark cycles and therefore an ideal sleep time is 10pm – 6am give or take ½ an hour either way so a full 8 hours of sleep is achieved each night. Even if you are retired or not working, this is an essential component of good sleeping habits.
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.
Most scientists agree that the most likely reason why 17-year cicadas spend so long underground is to avoid predators. By coming to the surface in such a large group, some cicadas get eaten but many cicadas will survive.