All important sleep - the foundation of good health

General Health

For the third part of our sleep, energy and stress series, nutritionist and lifestyle coach Effie Parnell-Hopkinson explains how a good nights sleep is crucial for good health and wellbeing.


Effie Parnell-Hopkinson
MSc BDA & SENr Registered Nutritionist

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Would you believe me, as a nutritionist, if I said I thought sleep was potentially just as important than diet and exercise? Well, here I am telling you exactly that. Despite the rise in information regarding the importance of sleep, a large majority of the population are still suffering from poor sleep. Considering sleep quality and quantity is entirely within our control and has such a large impact on our physical and mental health, surely it is something that we should start to prioritise?

In the modern world, it is becoming increasingly difficult to get adequate quality sleep at the right times due to factors such as longer working days, increased stress levels, increased artificial light and blue light exposure and lack of sleep hygiene. It may seem impossible to get away from these external factors that are detrimental to your sleep but there are ways you can begin to improve your sleep straight away. Before I go through my top tips, it is important to understand exactly why sleep is so crucial for your health, how much sleep you actually need, the negative effects of lack of sleep and how to improve your sleep.

Why is sleep important?

Getting enough sleep is vital and can help to protect your physical health, mental health, quality of life and safety. Our bodies need sleep to function during the waking hours and in fact, we spend a third of our lives sleeping and rightly so! Sleep is an active period where important processing, restoration, and strengthening occurs that is essential for our daytime alertness and functioning. During sleep, the body is working hard to support healthy brain function, to grow muscle, repair tissue and synthesize hormones. In children, getting adequate sleep is important as it also helps to support growth and development. One of the vital roles of sleep is the consolidating and solidifying of facts, information and memories that occur throughout the course of the day. The process of moving this information from the short-term memory to the long-term memory is known as consolidation and research has shown that people who get better sleep after learning have higher memory and information retention [1]. On the other hand, sleep deprivation can cause brain function to diminish making including decision making, solving problems, controlling emotions and coping with change far more difficult. 

In terms of the physical benefits, getting enough sleep decreases the risk of developing heart disease, kidney disease, high blood pressure, diabetes and obesity [2]. So not only are you improving brain functioning, productivity and focus, you are also improving critical markers of health and therefore increasing your longevity and quality of life. As mentioned above, prioritising sleep will do wonders for weight control and healthy hormone secretion and balance. Sleep helps maintain a healthy balance of the hormones that make you feel hungry (ghrelin) or full (leptin), and when you don't get enough sleep, your level of ghrelin goes up and your level of leptin goes down [3]. This imbalance makes you feel hungrier than when you're well-rested [4], hence that well-known feeling of wanting to eat junk when you’ve had a bad nights sleep!

So, how much sleep is enough?

The amount of sleep a person needs varies from person to person and changes between different age groups, for example, a child between the ages of 6 to 12 years old requires approximately 9 to 12 hours a day whereas an adult aged 18 and over requires 7 to 8 hours of sleep a day [5]. If you find that you are consistently losing sleep, this adds up and is known as sleep debt. You should aim to minimise your sleep debt by increasing your hours of sleep at night and not by occasional naps. Naps are a great way to top up your sleep and should be run in 90-minute cycles as this allows for both REM (rapid eye movement) and deep sleep. However, naps don’t provide the full benefits of a nighttime sleep so, although they provide a short-term boost in alertness and creativity, they shouldn’t be relied on.

Sleeping when your body is ready to sleep is an important factor to take into consideration and is something that is being made more and more difficult in the modern world with the increase in external stimuli confusing our natural circadian rhythms. Our bodies were designed to align with the sun (daytime) and moon (nighttime), i.e. our biological nighttime, which is highlighted in the way melatonin rises and falls during these periods. When the body is exposed to blue light, the photoreceptors in the body respond and prepare the body for daytime. So when you are exposed to this blue light in the evenings, your melatonin secretion is suppressed, leaving your body awake and ready for the day… only it’s nighttime, not ideal! To put it into context, for every hour spent near something that emits blue light (your phone, tablet, TV, fluorescent light) your melatonin production is suppressed by 30 minutes which suggests you should employ a screen curfew at the very least 60 minutes before bedtime.

Additionally, just one night of sleep deprivation increases cortisol production and suppresses melatonin which consequently impacts the body’s ability to breakdown brown adipose tissue [6]. This finding was also shown in people who were on a calorie-restricted diet with one group getting enough sleep and the other sleep deprived (8.5 hours a day vs. 5.5 hours a day, respectively). Those who were well rested burned 55% more body fat compared to the sleep-deprived individuals [6].

So there we have some of the benefits of getting good nighttime sleep and what happens if you deprive yourself of sleep. From the evidence, we can clearly see that getting good quality sleep, for the right amount of time, at the right time is vital for optimal brain functioning and productivity, physical health, heart health and overall quality of life.

But how do we go about improving our sleep?

Here are examples of things you can start to implement to help improve the quality of your sleep:

1. Create bulletproof sleep hygiene
Sleep hygiene isn’t about how clean your bedroom is, it refers to the different practices and habits that you create that are necessary for you to have good nighttime sleep quality and full daytime alertness. Whether that’s taking a warm bath, reading, stretching or all of the above! Finding a routine that works for you is key and ensuring you implement this consistently will send the signals to your body that you are preparing to go to sleep. Once you begin to turn these signals on in a consistent manner, your body will begin to recognise these signs quicker.

2. Maximise your sleep environment
Thermoregulation is a critical determinant of both falling asleep and staying asleep. A marked increase in blood vessel dilation, resulting in a decrease in body temperature, occurs as the body prepares for sleep and is one of the main signals for the onset of sleep. Any changes in ambient and body temperatures will affect the body’s circadian rhythms and interrupt the normal physiology of sleep [7]. So keeping your bedroom at around 17-20°C (62-68°F) will stimulate these signals and help to promote sleep. 

3. Stay away from stimulants (alcohol, caffeine, nicotine etc) before bed
Although alcohol is a relaxant and has been used for many years as a way of promoting sleep, research has shown alcohol negatively affects sleep quality, sleep duration and increases sleep disturbances, as well as higher reported daytime dysfunction [8]. Similarly, nicotine and caffeine are both stimulants and decrease the quality of sleep and sleep duration [9, 10]. So maybe it’s time to ditch the nightcap and focus on improving your sleep hygiene to promote sleepiness!

4. Natural sunlight exposure
Sunlight exposure suppresses the production of melatonin, which is exactly what we need to get rid of the morning grogginess and start our day on the right foot! Light exposure also increases the production of cortisol which also helps with suppressing melatonin secretion, as they work in opposites! If you work in an office or indoors, take some time to go for a walk or eat your lunch outside. This exposure to the sunlight will also help increase the production of serotonin, which after 10 hours or so will be converted to melatonin, helping to promote sleep in the evening!

5. Limit evening blue light exposure:
Your body interprets the blue light from your devices and TV screens you use in the evening as ‘daytime’, confusing our circadian rhythm and consequently our hormone secretion. For every hour spent exposed to a device, melatonin production (remember the hormone that helps you sleep) is suppressed by 30 minutes. To promote the biological body clock and re-sync our circadian rhythms to the sunlight and moonlight (how we used to run our days!), introduce a screen curfew at least an hour before bedtime.

So there are a few tips that you can start to implement to ensure you achieve a good night time sleep as well as full daytime alertness! Remember, sleep is the foundation of health and without it, our overall physical and mental health will start to deteriorate.

Competition time!

As part of our sleep, energy and stress series we have put together an exciting competition to win a spa day for two, a Medichecks Cortisol Test and a Dodow sleep aid to help improve your sleep, alleviate stress and get the spring back in your step. Enter here for your chance to wine. Competition entry closes midnight Thursday April 4th.


[1] Rasch, B., & Born, J. (2013). About sleep's role in memory. Physiological reviews, 93(2), 681-766.

[2] Cappuccio, F. P., Cooper, D., D'Elia, L., Strazzullo, P., & Miller, M. A. (2011). Sleep duration predicts cardiovascular outcomes: a systematic review and meta-analysis of prospective studies. European Heart Journal, 32(12), 1484-92.

[3] Taheri, S., Lin, L., Austin, D., Young, T., & Mignot, E. (2004). Short sleep duration is associated with reduced leptin, elevated ghrelin, and increased body mass index. PLoS Med, 1(3), e62.

[4] St-Onge, M. P., & Shechter, A. (2014). Sleep disturbances, body fat distribution, food intake and/or energy expenditure: pathophysiological aspects. Hormone Molecular Biology and Clinical Investigation, 17(1), 29-37.

[5] National Sleep Foundation. How Much Sleep Do We Really Need? (

[6] Nedeltcheva, A. V., Kilkus, J. M., Imperial, J., Schoeller, D. A., & Penev, P. D. (2010). Insufficient sleep undermines dietary efforts to reduce adiposity. Annals of internal medicine, 153(7), 435-41.

[7] Tsuzuki K., Okamoto-Mizuno K., & Mizuno K.(2004). Effects of humid heat exposure on sleep, thermoregulation, melatonin, and microclimate. Journal of Thermal Biology, 29, 31–36.

[8] Park, S. Y., Oh, M. K., Lee, B. S., Kim, H. G., Lee, W. J., Lee, J. H., Lim, J. T., … Kim, J. Y. (2015). The Effects of Alcohol on Quality of Sleep. Korean journal of family medicine, 36(6), 294-9.

[9] National Sleep Foundation. Caffeine and Sleep (

[10] Dugas, E. N., Sylvestre, M. P., O'Loughlin, E. K., Brunet, J., Kakinami, L., Constantin, E.& O'Loughlin, J. (2017). Nicotine dependence and sleep quality in young adults. Addict Behav, 65, 154-160. 

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