How much sleep do I need? Plus, why being sleepy doesn’t mean you’ll go to sleep

Dr. Harris reveals how much sleep you really need, the difference between ‘sleepy’ and ‘fatigued’, plus she reveals the many factors that prevent you from drifting off, even when you think you are tired.




The optimal hours of sleep 

Not sure if you're getting enough sleep? Generally speaking, different age groups need different durations of sleep and the amount of sleep we get is key. While there is no such thing as normal sleep, there is such a thing as an optimal amount of sleep. 


Babies, children and teenagers need more hours of sleep than adults and the older you get the less sleep you need, this is because when we're resting our bodies and brains develop, so a longer sleep duration is important for a growing child. 


Adults need around seven to nine hours of sleep but, of course, this can vary by individual. Some need more sleep and others less, but the goal is to wake up feeling refreshed - that's the sign of a good night's sleep. And, when you go to sleep is just as important as how many hours of sleep you chalk up. Better sleep occurs before midnight, so it's key to get ahead with a couple of hours before the clock strikes 12. One study found that those who went to sleep at 10pm were found to have a lower risk of cardiovascular disease. While another study of 400,000 people conducted over more than six years found that those who got to bed earlier had a longer life expectancy. 


How much sleep by age 

  • Infants (0-3 months) = 14-17 hours sleep per day. 
  • Infants (4-11 months) = 12-15 hours sleep per day. 
  • Toddlers (1-2 years) = 11-14 hours sleep per day. 
  • Preschool children (3-5 years) = 10-13 hours sleep per day. 
  • Children at school (6-13 years) = 9-11 hours sleep per day. 
  • Teenagers (14-17 years) = 8-10 hours sleep per day. 
  • Generally, most adults need between 7-9 hours sleep, however this may vary with some finding 6 hours is enough and others needing up to 10 hours. 
  • Older adults (65 and older) typically need 7-8 hours of sleep. 


The importance of a sleep schedule 

Humans are creatures of habit, so if you're regularly altering the times you are falling asleep and waking up you'll end up sleep deprived and racking up a sleep debt that's hard to pay back. 


Sleep patterns are key. If you're a self confessed night owl, but want to reap those pre-midnight sleep benefits then you need to work towards a steady routine. A sleep schedule where you have a set bedtime and morning call, seven days a week (not just on work days), will help you get into a healthy sleep routine and you'll find - with practise - going to sleep at 10pm will be possible. 


The sleep stages to know 

Let's quickly delve into the science that occurs during your hours of sleep. Our sleep can be broken down into sleep cycles of 90 to 110 minutes and each sleep cycle can be broken down into different stages... 


N1 - Light Sleep 

This consists of around 5% of your sleeping time and is the lightest stage. 


N2 - Deeper Sleep 

During this stage your heart rate and body temperature drops and it's this deep sleep that is thought to support memory consolidation. Overall this stage makes up 45% of our night's sleep. 


N3 - Deepest Non-REM Sleep 

The deepest stage of sleep, it is the hardest to wake from. If you are awoken during this stage you will likely feel extremely groggy. This stage is important as it is during this time that your body repairs, regrowing tissue and strengthening the immune system. However, it is also during this stage when sleepwalking and nightmares can occur. 


REM Sleep 

It's during REM sleep (that accounts for around 25% of our night's sleep) that our brains are active and we tend to have the most vivid dreams. We're often most likely to wake up during this stage of a sleep cycle. 


How to get more deep sleep 

Deep sleep is important for our mental and physical health and so it's wise to try to do everything you can during the day to optimise this stage once you're asleep. Here are some sleep habits to try: 

  • Eat more fibre 
    One study found that increased fibre intake (think whole grains, bran cereals and beans) resulted in increased deep sleep. 
  • Exercise daily 
    Numerous studies have linked exercise to improved sleep. Be sure to factor an intense workout earlier in the day, because if you exercise too late in the evening it can actually be detrimental to your sleep health. 
  • Avoid caffeine 
    Want to support a good night's sleep? Avoid caffeine for around seven hours before going to bed (and skip that late night glass of wine, alcohol affects sleep quality too). 
  • Wear earplugs and eye masks 
    It sounds obvious but a dark quiet room is the best sleep environment for a good night's sleep. If you room isn't optimal, then the use of earplugs and eye masks will help. 


What to do if you struggle to fall asleep by Dr. Shelby Harris 

Struggling to fall asleep at the beginning of the night is an extremely common problem. But one of the biggest culprits is something we rarely pay much attention to: the difference between sleepiness and fatigue. 


Although they’re frequently confused, in fact there is a big difference between the two. It doesn’t mean both can’t exist at once, but most often the issue with falling asleep is getting into bed when you’re fatigued but not actually sleepy. So how do you tell if you are indeed sleepy? 


I like to think of fatigue as that feeling of dragging a ton of bricks behind you - no energy, no gas in your tank. One of the common complaints about being fatigued, but not sleepy, is that you desperately want to take a nap but are completely unable to doze. That’s because you’re tired and fatigued, but not actually sleepy. 


Many people with insomnia frequently try to nap to compensate for a poor night’s sleep – but indeed, they’re fatigued and not sleepy. Common fatigue symptoms include dragging, sluggishness, mental fog/cloudiness, inability to nap even if desired, and a lack of energy. 


Meanwhile sleepiness is the actual act of falling asleep. Napping and even dozing at times when you are sedentary or quiet (even if unintentional) are all signs of sleepiness. Other common sleepiness signs include struggling to keep your eyes open, lapses in alertness, eyes tearing up, yawning and even a heaviness in your body (especially limbs). 


 From today, try and see for yourself how your body signals sleepiness versus fatigue. This can prove invaluable for timing when to actually go to bed for the night. Try and learn your true sleepiness signals (mine are always yawning, eyes tearing up and struggling to keep my eyes open). Pairing the bed only with sleepiness and sleep teaches the body that the bed is indeed for sleep, not just resting, tired, and thinking (which often happens with a busy brain). And if you get into bed when you’re genuinely sleepy, not just fatigued, you’ll improve your chances of falling asleep faster. Good luck. 


If you have significant issues with daytime sleepiness, and a nap doesn’t help or you can’t get through the day without multiple naps, talk with your doctor to rule out any other medical or psychiatric issues. Excessive daytime sleepiness shouldn’t be ignored. 



Not sure if you’re physically tired, mentally fatigued or just sleepy? Try this revitalising meditation to refresh your energy and relax all over. 



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Shelby Harris

Shelby Harris

Dr. Shelby Harris is a Rituals Ambassador for Sleep, and a licensed clinical psychologist. With years of experience treating a wide variety of sleep disorders she uses evidence-based methods and non-pharmacological treatments to improve sleep for everyone from babies to adults. Dr. Harris currently holds a dual academic senior-level appointment as Clinical Associate Professor at the Albert Einstein College of Medicine in both the Neurology and Psychiatry Departments. and is board certified in Behavioral Sleep Medicine (BSM) by the American Academy of Sleep Medicine. She’s also the author of The Women’s Guide to Insomnia.