Sleeping Time: How Many Hours of Sleep are Needed?

Author: Sylvia Liebenberg 

You’ve been staring at your screen for… how long has it been? What were you doing before you lost track of what you were doing? Oh wait, you were going to get another cup of coffee. But caffeine doesn’t even help anymore, you just feel continuously tired and drained. If this is you, then you are probably not getting enough sleeping time each night. But how many hours of sleep are needed? Glad you asked! Sleep expert Sylvia Liebenberg spoke to The Mattress Warehouse about why you need sleep and how much of it you need. So if you feel like you’re not getting enough sleep (or maybe too much) keep reading for some great sleep tips.

What is sleep?

Sleep is the body’s natural rest cycle. The onset of sleep is triggered by the release of a complex sequence of hormones, notably melatonin, a hormone that plays a role in governing your circadian rhythm (24-hour cycle). Quality sleep consists of four sleep stages that are repeated a couple of times per night. During each sleep stage, certain body functions take place, like memory consolidation, muscle repair etc. More on that in a bit.

Why do we need sleep?

The simple truth is that we can’t live without sleeping. Our 24-hour cycle helps regulate the course of our body functions. Some functions take place during the day, and others at night, while you sleep. But if you don’t sleep,  these functions don’t occur sufficiently and that could lead to health problems.

Think about it like this; if you don’t drink water, you’ll become dehydrated, which may lead to health complications if it happens too often. Likewise, if you don’t eat enough, your body becomes malnourished, once again leading to health issues. Similarly, if you don’t get enough sleep, you become sleep deprived, and if it becomes a regular thing, it may bring about some health problems.

Here are some reasons why your body needs sleep:

1. Growth and cellular restoration – While you sleep, your pituitary gland produces growth hormone. This hormone stimulates cell regeneration and -reproduction, which aids in growth (while you are still growing) and muscle recovery. It also regulates your metabolism and subsequently, insulin production.
2. Immune function – If you do not sleep enough, your immune system becomes compromised because your body cannot produce enough cytokines to fight off inflammation and infection.
3. Brain function – During the day, your brain uses sugar and fat as energy sources to function. And as a result of that, there is a build-up of waste products in the brain. When you are in deep sleep, your brain gets rid of the built-up toxins. Also, your brain processes information and stores your memories in folders while you sleep.

If your metabolism functions well, your immune system is fully operational and your brain is clear, your quality of life is significantly better than if the inverse was true.

To better understand what happens when you sleep, let’s take a look at the various sleep stages.

Sleep stages explained

As we’ve already mentioned, sleep experts distinguish between four different stages of sleep. The first three stages are known as non-Rapid Eye Movement, or non-REM sleep and consist of light- and deep sleep. The final stage is REM sleep, where your brain activity differs from the other three sleep phases.

Stage 1 – Drowsiness

Phase one is not actual sleep, but a feeling of drowsiness. During this sleep stage, you will experience a transition from wakefulness to sleep. Due to the nature of the first sleep stage, you spend by far the least amount of sleeping time in the drowsiness phase.

Stage 2 – Light sleep

Not a lot of physiological processes take place during light sleep. However, it is already difficult to wake someone from stage 2 sleep. Light sleep is part of the resting phase and as such, contributes to restfulness. About 50% of your sleeping time is light sleep.

Stage 3 – Deep sleep

When you look at your total sleep time, you should spend about 20% to 25% in deep sleep. During deep sleep, your body gets rid of all the built-up waste products in the brain. During this sleep stage, your body bolsters your immune system and fights inflammation. Moreover, you also release critical hormones and neurochemicals like serotonin (the feel-good chemical in your brain), growth hormone, and testosterone during deep sleep.

If you do not get enough deep sleep, muscle recovery will be slower, and you may likely be more susceptible to illness.

Stage 4 – REM sleep

Rapid Eye Movement sleep (REM) is essential for your cognitive functions. During REM sleep, your brain basically defragments and processes information. Your brain sifts through what happened during the day, organising and storing information in your memories. During REM sleep, your brain also discards useless information. For instance, you don’t need to remember how many green traffic lights you encountered throughout the day and so to free up memory space for important matters, your brain discards that kind of info during the final sleep stage.

REM sleep is very important for your concentration and your memory – you need REM sleep to remember and you need REM sleep to forget. Without enough REM sleep, you won’t be able to focus and make critical decisions during the day.

You should spend roughly 20% of your sleeping time in REM sleep.

Interesting tidbit: A lot of children that are diagnosed with ADHD are only suffering from poor quality sleep as sleep deprivation and ADHD symptoms present quite similar.

What do these symptoms look like?

8 Signs you’re not getting enough sleep

Having trouble waking up? You may not be getting enough sleep.

Some effects show after one bad night, whereas others only present over time. Let’s take a look.

1. Waking up and feeling groggy/brain fog. Your eyes are red, and they burn or feel itchy. These physical symptoms can be identified after a single night of not sleeping well.
2. Mood swings – If you sleep poorly over a period of time, your emotional state becomes affected. Mood swings are common, you become more irritable, and depression may kick in.
3. Lack of motivation – You don’t feel motivated and you do not want to do things you used to enjoy doing. This is because of a lack of serotonin.
4. Gain weight – You need high enough growth hormone levels for your metabolism to function properly. If you don’t get enough deep sleep your growth hormone levels go down, and as a result, your metabolism doesn’t function. You may start picking up weight without making any changes to your lifestyle.
5. It Affects insulin production in the pancreas, which leads to insulin resistance and can, in time, even lead to type 2 diabetes. That is why many people with sleep disorders also suffer from diabetes.
6. Craving high-carb food and caffeine – This is a subconscious way for your body to fight off the symptoms of sleep deprivation.
7. Testosterone levels drop – This leads to low libido and low energy levels. It also affects your muscle and bone strength, so if you do not sleep enough, you become more susceptible to injury (especially if you are an active person).
8. Compromised immune system – You are more susceptible to disease if you don’t sleep enough. White blood cells are a critical part of the immune system. Moreover, one of the white blood cell types, the T cell, circulates your body and identifies abnormal cells like viruses and bacteria. T cells then attach to the abnormal cell and destroy it, simultaneously sending out a signal to the rest of the body to be on the lookout for similar invaders. If you don’t get enough sleep, T cells lose the ability to attach to abnormal cells and destroy them.

It is important to note that with babies and children, sleep is a fairly complex matter, and sleep disorders can’t be as easily diagnosed as with adults. Before diagnosing a sleep problem in kids, a comprehensive medical exam must be conducted to ensure that there are no underlying problems. Sleep studies are much more indicative in adults than in children; that is why, at the Sleep Clinic, we focus more on adult sleep therapy.

Why does caffeine keep you awake?

Inside your brain, there are differently shaped receptors for various neurotransmitters to bind to – almost like a keyhole where only a specific key fits. So specific receptors bind to specific chemicals. Caffeine binds to the same receptors as adenosine – an important chemical for sleep. And if caffeine is already bound to a receptor, adenosine can’t bind there. So the more caffeine you drink the less adenosine will bind to the receptors and hinder the onset of sleep. That is why dieticians recommend that you avoid caffeine too close to bedtime.

How many hours of sleep are needed?

As you age, you need less and less sleep. Babies need a lot of sleep to grow and develop, whereas fully-grown adults can get away with a bit less sleep.

• Babies: sleep 14 – 17 hours (ironic because when they sleep most, parents sleep the least)
• 3 months to 1 year: 12 – 15 hours on average
• 1 – 3 years: 11 – 14 hours
• 3 – 5 years: 10 – 13 hours
• 6 – 12 years: 9 – 11 hours
• 12 – 18 years: 8 – 10 hours
• >18 years: 7 – 9 hours

From 6 months on, healthy babies should be able to sleep 6 to 7 hours at a time because they don’t need to feed so often.

How many hours of sleep do adults need?

Once you stop growing, some medical sources recommend 6 to 8 hours of sleep per night, whereas others recommend 7 to 9 hours. However, these are just guidelines and not a set rule. You have to experiment and see what total sleeping time per night works best for you.

How much sleep is too much?

Too much sleep is a very difficult thing to measure. Some people spend too much time in bed but do not necessarily sleep too much. Others sleep too long because of sleep disorders such as sleep apnea which take away from their ability to get good quality sleep. So they just end up with a lot of sleeping time, of which most is light sleep, and very little is restful deep sleep.

Interestingly, the symptoms that you see in people that sleep too much are similar to the symptoms you would see in people with insomnia. It also overlaps with some of the signs you’re not getting enough sleep. For instance, heart disease, diabetes, and obesity.

People who sleep too much because they enjoy sleep or just spend too much time sleeping, lose their potential to sleep.

What do we mean by the potential to sleep?

During the day you need to be physically and mentally active to build up your sleep potential. Basically, the more productive you are during the day the more likely you are to have a good night’s rest. On the other hand, if you sleep too much, you decrease that potential  (you are not tired enough) and end up spending less time in deep sleep and REM sleep. The end result is the development of symptoms that go along with a lack of deep sleep and REM sleep, even if you sleep for ten hours on end.

Sleep tips: getting good quality sleep

Sleeping for long periods during the day may reduce sleep quality at night.

Here are some sleep tips to help you get the right amount of sleeping time every night.

• Routine – This is probably the most important sleep tip. Try to stick to the same sleeping schedule – go to bed around the same time and get up around the same time every day (even on weekends). If you go to bed three hours later than usual and you subsequently get up three hours later, you create an artificial jetlag effect in your own body. It also affects your circadian rhythm, making it difficult to get back into your regular sleep schedule. This is super important if you naturally struggle to sleep.
• Lighting is important – Before electricity, people went to bed with the sun and got up with the sun. But with the advent of electricity, that changed. Now we stay up late because we still have light. But you can determine what type of lighting you use. Instead of using bright, white lights, use yellow globe lights and lamps. And just so you know, melatonin only secretes when it is dark.
• Exercise but not late at night. If possible, try to do your daily exercise in the early morning. And if that is not possible, try to do it in the afternoon before 6 pm because it will act as a stimulant.
• Listen to your body – Go to bed when you feel sleepy.
• No TV in your room – Switch off your TV 1 hour before bedtime. Likewise, do not work on your computer before you go to bed as the blue light will stimulate your brain.
• Wind down time – Take a shower, read a book, do some yoga, and relax. Whatever you do to relax, you need some time for your sympathetic nervous system to deactivate. When you get busy during the day a lot of adrenalin and cortisol circulate through your body and you need to get rid of that before you can fall asleep. That is where the wind-down time comes in.
• No heavy meals before bed.

Sleeping time tips from The Mattress Warehouse

You can now effectively identify if you get enough sleep and if you don’t… Well, then you have some great sleeping tips that you can try out. And if that doesn’t work, visit the Sleep Clinic for an expert consult and perhaps some sleep tests. For more sleep tips, visit our Blog.

About Sylvia

Sylvia holds a B.Sc (Human Physiology and Psychology) from The University of Johannesburg and a B.SocSci(Hons) in Psychology with a specialisation in neuropsychology from The University of Pretoria. She is also qualified as a neurofeedback therapist and EEG Technician. Sylvia believes that the effects of sleep are one of the most visible examples of how our physical and mental health is intertwined. She has been at the Pretoria Sleeplab for twelve years, where she’s gained extensive knowledge and experience in a variety of different sleep disorders.

Disclaimer: The views and opinions expressed in this article are those of the author and do not reflect the views of The Mattress Warehouse.