Sleep and screen time: what you should know

Kate Bristow, a diabetes nurse educator, gives a rundown of all you need to know about sleep and screen time.

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World Sleep Day is 15th March.

As children we are told that we need to sleep because sleep is good for us. That’s not just parents trying to get peace and quiet, it’s for real.

Getting less than seven hours of sleep at night on a regular basis can be risky to your health. So, when talking about how screen time affects sleep patterns, it’s best to understand why sleep is important, just like a good diet and exercise is also a priority. 

Why do we need to sleep?

Please note for reference purposes, we are talking about less than seven hours of sleep per night.

Weight management 

  • Studies have shown that adults who don’t sleep enough have a higher risk of weight gain and obesity.
  • Lack of sleep increases the levels of ghrelin, which is the hormone that makes you hungry, and decreases the levels of leptin which is the hormone which makes you feel fuller.
  • People who are sleep deprived tend to be hungrier and eat more, and to compensate for the lack of energy they may crave foods higher in sugar and fat.
  • If you are feeling tired, you are less likely to hit the gym or do any physical activity which you may normally enjoy.

Brain function 

  • Research into sleep has shown that getting enough sleep improved academic performance, problem-solving skills and memory in both adolescents and young adults, possibly also in older folk, but there seems to be less research done here.

Athletic performance 

  • Better sleep enhances athletic performance, fine motor skills and endurance as well as reaction time.
  • Lack of sleep decreases your motivation to actually get out there and exercise, which is beneficial to glucose levels and your mental well-being.

Your health

  • Poor quality sleep and less duration of sleep has been shown to increase the risk of developing heart disease and high blood pressure.
  • Shorter sleep duration is also associated with a risk of developing insulin resistance and diabetes, which along with the risk of obesity and heart disease also associated with lack of sleep leads to metabolic syndrome.
  • Poor sleep is strongly associated with depression. This includes poor quality sleep and sleep apnoea as well as insomnia.
  • Your general immunity is reduced by poor sleep patterns. Getting at least seven hours of sleep has been shown to improve immune function to fight the common cold and flu.
  • Sleep disturbance has been associated with higher levels of general inflammation.
  • Chronic inflammation can cause development of many chronic conditions such as obesity, heart disease, some cancers, Alzheimer’s disease, depression and Type 2 diabetes.


  • Lack of sleep affects your ability to interact socially, resulting in emotional outbursts and behaviours such as social withdrawal. 

Danger to yourself and others 

  • When you are tired, your ability to focus on tasks, your reflexes and your reaction times are affected, in a similar way to having consumed large amounts of alcohol.
  • Less than six hours of sleep increases the risk of falling asleep at the wheel exponentially.
  • Errors at work are also a risk with poor sleep habits.

To sum all this up: sleep along with a good eating plan and exercise is one of the pillars of good health.

Managing screen time

Along with getting enough sleep, with the increased use of technology nowadays, you also need to take into account the amount of screen time you have before you settle in for the night.

How does watching TV or playing on phones, computers or Ipads before bed actually affect health and sleep quality?

These issues arise with the use of technology and screens:

  • You spend more time in front of screens, giving you less available time for sleep.
  • What you watch/play causes psychological and physical stimulation of your senses as well as social interaction which interferes with the ability to sleep or stay asleep.
  • The light from screens affects your circadian rhythms and your alertness.

 What are circadian rhythms?

  • Defined as the natural cycle of physical, mental and behaviour changes that the body goes through in a 24-hour cycle.
  • Light and dark have the biggest influence on circadian rhythms, but your food intake, stress levels, physical activity, social interactions and temperature can also have an effect.

In a nutshell, circadian rhythms are a series of body functions that control cycles such as sleep, being awake, your body temperature, your hormones and a whole lot more.  It’s important to maintain your circadian rhythms consistently by having stable bedtimes and wake-up times, aiming for a healthy seven to nine hours of sleep a night.

 How is the circadian rhythm affected by screen use?  

  • This is how it works: when it’s time to sleep your body produces a hormone called melatonin. Melatonin is produced in the pineal gland, a tiny organ in the middle of your brain which helps control your body’s sleep cycle. It’s also an antioxidant.
  • The bright light from screens supresses the production of this hormone, which affects the quality of your sleep.
  • It’s also estimated that most of us spend at least seven hours a day in front of a screen. The effects of this on general health, physical activity, cognitive function and social interactions are continually being researched, and there is still need for further research.
  • Consistent findings from a number of studies associate screen time with decreased duration of sleep and sleep problems.
  • Also to be noted in the research was the fact that in the advancement of technology, there may be stacking of screen time. What this means is that a single person may be using more than one screen at any one time. For example, as I write this article, I have the television on in the background, my cell phone at my side – and yes, I’m checking it regularly, and my computer on my lap. Three screens – not unusual anymore.

 Youth and screen use

The harm of the use of screens, particularly on our young people and the consequences of this in sleep patterns is still under research, and as technology advances and changes, this will be an ongoing field of study. Research thus far is showing that the use of screens of all types is linked to delayed bedtime and not enough sleep in our young people. This includes preschoolers, children of school-going age and adolescents.

  • Insufficient sleep has been associated with a risk of obesity in children, mental health issues as well as impaired cognitive and academic abilities.
  • You may have put a TV in your bedrooms to help you fall asleep. Parents use TV to help children wind down in the evening, and people use calming apps now to help them fall asleep. There has also been suggestion that people who leave an electronic device on in their bedroom after bedtime also have less total sleep as well as poorer quality of sleep as well as daytime tiredness.
  • The brightness of the screen over a long period of time has also been shown to increase alertness before sleep. Screen brightness increases arousal and decreases sleepiness at bedtime and delays the onset of the circadian rhythm, which in turn delays the onset of sleep. If the same wake time is set, the total duration of sleep is therefore shorter.
  • Light-emitting screens have also been shown to suppress the blood levels of sleep-inducing melatonin, which is supposed to increase in the hours prior to bedtime, blue light screens are the ones which suppress the production of melatonin the most. This means less sleepiness at bedtime and interference in the sleep cycle.
  • Delayed bedtimes, and things like violent video games, also increase stimulation before bed, as do TV shows which excite and stimulate your senses.

 AAP guidelines

The American Association of Paediatrics (AAP) has issued guidelines which recommend that any screen-based activities be stopped 30 minutes before bedtime, and that screens are not allowed in bedrooms, to try to reduce exposure in preschool children.

 The link to diabetes

So, if you understand what screen time does to your health in general, how do you tie this up to your diabetes health? There are so many reasons to get a decent night’s sleep and for some of us this may feel like a luxury. Stats in America show that 1 in 3 adults don’t get enough sleep and this increases the risk for developing Type 2 diabetes, heart diseases, obesity or depression.

When you have diabetes, lack of sleep can affect every aspect of how you manage it: your food choices, the amount you eat, how you respond to insulin as well as your mental health. Good sleep puts you in a better mood and gives you more energy.

 Too little sleep can:

  • Increase insulin resistance
  • Make you hungrier
  • You may be more likely to reach for comfort food – high in carbs and sugar
  • Make weight management more difficult
  • Increase blood pressure and increase the risk of heart disease
  • Decrease your general immunity
  • Increase your levels of depression and anxiety

 Tips to improve the quality of your sleep

  • Your bedroom should be dark, quiet and cool (a relaxing space).
  • Remove all electronic devices from the bedroom. This includes TVs, computers and smartphones.
  • Get some exercise in the day.
  • Do some relaxation exercises before you go to bed.
  • Have a regular bedtime routine – take a shower, read or write in a journal.
  • Get into bed when you are tired.

Things you can change

  • Caffeine can affect you for up to eight hours. Avoid it in the afternoon and the evening.
  • Alcohol can affect how you breathe when you sleep and it affects your sleep quality.
  • Avoid large meals in the evening. Late meals can cause indigestion and raise blood glucose levels.
  • Try not to nap after 3pm so you are tired at bedtime.
  • Avoid nicotine; it has the same effect as caffeine.

To sum things up, all the evidence points to the fact that as humans in general we all need better sleep practices and avoid screen time at night. We need to have routine and discipline in our sleep routines just like we do in our dietary choices and our exercise. By doing this we will lead to better long-term health and better quality of life.

Sister Kate Bristow is a qualified nursing sister and certified diabetes educator.


Sister Kate Bristow is a qualified nursing sister and certified diabetes educator. She currently runs a Centre for Diabetes from rooms in Pietermaritzburg, providing the network support required for the patients who are members on the diabetes management programme. She also helps patients who are not affiliated to a diabetes management programme on a private individual consultation basis, providing on-going assistance and education to assist them with their self-management of their diabetes.

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