Why sleep is so important

Our bodies need to sleep to function and a lack of sleep can have a dramatic effect on our wellbeing. When we sleep, it gives our bodies a chance to restore chemical balance and to heal. In addition, our brains forge new connections and help us with memory retention.

We all know that getting around 8 hours of sleep is recommended for optimum health, but many of us don’t manage this for a variety of reasons. Modern day life gives us the ability to be connected 24-7 but the use of computers, smart phones and working into the evening means that our bodies aren’t being given the chance to wind down properly. If you’re waking up tired and struggling not to nap during the day, the chances are that you’re not getting enough sleep.

Most of us are aware of the obvious signs of sleep deprivation such as excessive sleepiness, yawning, irritability and daytime fatigue. But a lack of sleep can have far more serious effects if it continues long enough. Here are some facts about sleep deprivation that you might not be aware of.

Brain Power

We’ve mentioned how sleep helps with memory retention. During the night, various sleep cycles play a role in consolidating memories in the mind. A lack of sleep makes it hard to remember what you learned and experienced throughout the day. Sleep deprivation can impair cognitive processes such as concentration, attention, alertness and reasoning, so it’s easy to see how important sleep is for thinking and learning.

For more information read our article on the affects of sleep on memory

Serious Health Issues

When you sleep, your immune system is busy producing protective, infection fighting substances that help protect you from bacteria and viruses. With a lack of sleep, your immune system is unable to build up this protection and your body will take longer to recover from illness. What many people don’t know is that chronic sleep loss can lead to putting you at risk from far more serious conditions, such as heart disease, heart attacks, high blood pressure, stroke and diabetes.

Read our article on the increased risk of diabetes caused by lack of sleep


Lack of sleep can often lead to accidents. Sleep deprivation has been responsible for some of the biggest disasters in recent history, including the nuclear meltdown at Chernobyl for example. This is undoubtedly down to the fact that drowsiness can slow reaction time as much as being drunk. In everyday life, sleep deprivation is thought to be a cause in around 100,000 car crashes in the USA alone and also leads to an increase in work-related accidents and injuries.

Psychological Issues

Because sleep deprivation can leave your brain exhausted, it can’t perform its duties as well as it should. This lack of concentration and sleep can then negatively affect your emotions and mental abilities. Those suffering from a lack of sleep become more impatient and prone to mood swings, with decision-making processes and creativity stifled. Long-term sleep deprivation can also lead to far more serious psychological issues such as having hallucinations, paranoia, suicidal thoughts and depression. Studies show that those suffering with depression or anxiety are more likely to sleep less than six hours a night, with those suffering from insomnia five times more likely to develop depression. It can be a vicious cycle – with sleep loss aggravating the symptoms of depression, and depression making it harder to sleep. Treating sleep problems can often lead to the symptoms of depression starting to lift.

Read our article on the risk of mental health issues caused by lack of sleep

Weight Gain

Lack of sleep has been linked to an increase in hunger and appetite. There is a clear link between sleep and the peptides that regulate our appetite. Ghrelin stimulates hunger, whilst leptin suppresses it and shortened sleep time has been proven to be linked to decreases in leptin and increases in ghrelin. Sleep loss also seems to up our cravings for high fat, high carbohydrate foods. Indeed, studies show that those who sleep less than six hours a day are around 30% more likely to become obese.

For further information, read our article on the affects of sleep loss on weight


We’re all familiar with the black circles and puffy eyes that a few nights of bad sleep can cause. But chronic sleep deprivation causes your body to release more cortisol – a stress hormone. And in excessive amounts, cortisol can break down skin collagen, which is the protein that helps to keep skin elastic. Those suffering from a chronic lack of sleep will have sallow skin, more fine lines and darker black circles under the eyes. In addition, loss of sleep stops the body from releasing enough human growth hormone, which is responsible for strengthening bones and increasing muscle mass.

Sex Drive

Lack of energy and increased stress from lack of sleep often leads to less interest in sex and a lower libido. Sleep deprivation can also affect fertility in both sexes, with the secretion of reproductive hormones being reduced. Men who suffer from sleep apnoea (a disorder where breathing difficulties cause broken sleep) also have significantly lower testosterone levels and are therefore likely to suffer from a lower libido.

Hopefully, reading this article will help you see why sleep is so important – both for obvious and less obvious reasons. If this has inspired you to improve your sleep, why not have a read of our guide to getting better sleep?

How much sleep do we need?

We spend up to one-third of our lives asleep and, whilst most of us know that a good night’s sleep is important, too few of us make it a priority. How much sleep we need varies across different age ranges, but is also heavily impacted by lifestyle factors.

The National Sleep Foundation recently released the results of a study, which took more than two years to complete; into how much sleep we really need at each age. Research cannot pinpoint an exact amount of sleep, but can give recommended ‘windows’. However, it’s also important to factor in lifestyle choices to help you find your ideal sleep amount. Factors that need to be taken into consideration are whether you have any health issues or at risk for any diseases, if you experience sleep problems, if you depend of caffeine to get through the day or if you feel sleepy when you’re driving. Also consider if, for example, you are happy and productive on seven hours of sleep or whether you need a full nine hours to keep going the following day.

These are the recommended sleep windows for different age groups:

  • Newborns (0-3 months): 14-17 hours
  • Infants (4-11 months): 12-15 hours
  • Toddlers (1-2 years): 11-14 hours
  • Preschoolers (3-5): 10-13 hours
  • School age children (6-13): 9-11 hours
  • Teenagers (14-17): 8-10 hours
  • Younger adults (18-25): 7-9 hours
  • Adults (26-64): 7-9 hours
  • Older adults (65+): 7-8 hours

As for how much sleep you need as an individual give yourself a week to sleep and wake up without an alarm clock – such as when you are on vacation. Give yourself a few days to make up for any sleep debt you may have accrued and then note exactly how many hours sleep you need each night. Once you know this figure, you’ll be able to get the perfect amount of sleep for your body.

Where can I find out more?

If you are interested in learning more about the effects of sleep deprivation, this book we have recently read may be of interest. Night School: The Life-Changing Science of Sleep.

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