How Important is your Sleep?

Never mind the population of St Albans, but this goes for the entire UK population, we all know sleep is important, but few people realise that not getting enough sleep pretty much neutralises the benefits of healthy eating and exercise, visit our home page to find out about personal training and much more.

When we sleep, protein production takes place that provides the necessary building blocks for cell growth and repair: The body recovers from stress damage, damage caused by ultraviolet rays and immunity is boosted.

Without sufficient rest the body is weakened, exposing us to greater risk of poor health. Lack of sleep also wreaks havoc with our hormones.

Lack of sleep causes persistently high cortisol levels, which can cause a myriad of disorders, including thyroid and metabolic dysfunction, cognitive decline, low serotonin levels resulting in depression, irritability, anxiety and carb cravings.

Lost sleep affects physiological and cognitive functions like memory and attention, complex thought, motor response and emotional control. It also makes us pretty miserable, irritable, anxious and stressed.

So why then are we sleeping so little?

In 1909, gas, electricity and coal were expensive, so when the sun went down most people went to sleep.  Because of this, the average person slept for 13 hours per night. This decreased to about 7.5 hours in 1975, and is now at an all time average low of 6.5 hours, with many shift workers getting 5 hours or less.

Nowadays, when the sun goes down we simply switch on a lightbulb or watch the TV.  Because of this, we now live out-of-sync with the normal light/dark cycle, and we now average only 6.8 hours of sleep per night.  This is almost half the amount that we got a century ago.

Whilst we may like to convince ourselves that we can cope with very little sleep, there is more and more evidence that this lack of sleep is starting to affect our health.

You will experience trouble falling asleep and staying asleep. You will feel fatigued and irritable during the day. You will feel like you need a nap or two each day, feel more stressed and more down in the dumps than usual.

Abusing the sleep-wake cycle over a prolonged period can lead to the onset of insomnia, which has serious health risks.

The good news is that it’s easy to improve the quality of your sleep. Most cases of poor quality sleep and insomnia can be cured. We will show you some simple strategies later in this article.

More worrying than losing a couple of hours here and there is that a huge number of people are using medication to aid sleep.

An estimated 10% of the American population takes some form of medication to sleep. (National Sleep Foundation).

Sleep aids are bad news. A study headed up by Dr. Daniel Kripke of Scripps Clinic, compared 10,529 people that took sleeping pills with twice as many who didn’t.

The study revealed that those taking prescriptions were at a 35% increased risk of cancer compared with the non-prescription group. The study showed that the risk of developing lymphoma, lung, colon or prostate cancer associated with sleeping pills was greater than the effect from smoking.

It’s crazy. Rather than make positive, natural changes to our lifestyle and environment, we resort to sleeping pills, wake up pills, caffeinated drinks and other stimulants to get us through the day.

Sure, it’s challenging to find more time for sleep in an increasingly busy world – we’ve more to do and more to think about.

But the truth is we’ve also become our own worst enemy: We stay up too late, we eat too late, we stimulate the brain with computers and phones all day long, we constantly eat stimulants and we don’t give the brain adequate time to rest, relax and wind down each day before bed.

Our ancestors slept in alignment with Mother Nature. They went to sleep a few hours after the sun went down and woke with its rise. They ate a diet that complemented their sleep and properly exercised the mind and body to make it sufficiently tired for a good night’s sleep.

So what causes us to sleep?

There are two main mechanisms:

Firstly, when we wake up and move around, our body produces a substance called “adenosine”.  When the levels of adenosine rise to a certain point, the body recognises that the level needs to be lowered and so stimulates the sleep response in our body.  This makes us sleepy, because when we are asleep and not moving, the adenosine is removed and returned to a lower level.

The second mechanism are our natural 24hr cycle of hormones, known as circadian rhythms.  The main hormone linked to sleep/wake cycles is the hormone cortisol.

Sleep and Awake Cycles

This is the normal sleep homeostasis pattern.  When we wake up in the morning, the level of adenosine in our blood rises and this increases our “sleep need”.  In the morning, this leads to a rapid rise in “sleep urge”, which causes us to feel sleepy in the early afternoon.  A short powernap or siesta lowers our “sleep urge”, but does not have much of an impact on or “sleep need” as adenosine levels continue to rise.

Eventually, both our “sleep need” and “sleep urge” reach a critical point and this causes us to fall asleep to lower the adenosine levels in the body.  The reduction in adenosine reduces both our “sleep need” and “sleep urge” and resets us for the following day.

Normal rhthym of Cortisol

Normal rhythm of Cortisol

Cortisol is an energising hormone, that gives us energy and stimulates our hunger.

The release of cortisol into our blood usually has a very precise 24hr rhythm.  It is low throughout the night (which makes sense, because we don’t want to be full of energy when we are trying to sleep) and then rises rapidly when light (i.e. the sunshine) hits receptors on our body.  This means that cortisol is normally highest between 6am and 8am, meaning we should wake up at this time feeling full of energy and very hungry for breakfast.  After this time, cortisol levels drop fairly rapidly.  By 6pm to 8pm, cortisol levels should be fairly low so that we feel sleepy.  Low levels of cortisol stimulate the release of melatonin, which tells our body it is time to sleep.  Cortisol levels are lowest around 2am to 4am (when our sleep is deepest), and then rise rapidly when stimulated by light (sunshine).

Abnormal rhythm of cortisol – Adrenal Fatigue!

Abnormal rhythm of cortisol

However, when the adrenal glands are forced to work harder than normal (due to a high intake of teas and coffees, lots of little stresses and lack of relaxation), they lose their natural 24-hr rhythm and ability to respond to stressors.  Instead, their output changes so that they simply release a constant level of the hormone cortisol.

This means that when a person wakes up in the morning, the level of cortisol is too low, leading to feelings of tiredness in the morning.  Also, because cortisol stimulates the appetite, a low level of cortisol in the mornings mean that you wake up without an appetite and not wanting a breakfast.

Conversely, cortisol levels at the end of the day are too high.  Because cortisol is an energising hormone, it leads to a conflict within the body, whereby the person recognises that they need sleep and yet is unable to stop their brain whirring at a million miles an hour.  This is the classic “tired-but-wired” phenomenon. High Cortisol levels lead to higher levels of body fat storage particularly around the mid section on the body.

Sleep Architecture

Sleep Architecture

This diagram shows a person’s sleep architecture, or the make up of their sleep.

When a person moves from being awake to being deeply asleep, they follow a very specific pattern.

First, the person enters a stage of sleep known as Non-Rapid Eye Movement (NREM) 1, which is dominated by beta and alpha brain waves.  In this stage, the person is “dozing”, and is likely to be able to respond to a question (although will sound slightly sleepy).

After this stage, the person moves into NREM 2, which is dominated by alpha and theta waves.  In this stage, the person may appear asleep, but will still be able to respond if you called their name.  Some people in this stage often experience the sensation that they are falling and may jerk back awake.  NREM 2 accounts for approximately 50% of sleep.  NREM1 and NREM2 are both referred to as shallow sleep.

After NREM2, the individual passes into NREM3, which is dominated by theta and a small amount of delta waves.  The person will now be asleep.  After NREM3, the person moves into NREM4 (when more than 50% of the brain waves are delta).  This is the deepest level of sleep, and it appears that NREM4 is vital in regulating hormonal levels and physical repair.

After NREM4, the person moves back to NREM 3, then NREM2 and then into Rapid Eye Movement (REM) sleep.  REM sleep is where the person dreams, and is believed to be the main phase of psychological/cognitive “repair/restoration”.  After REM, the person moves back to NREM2 and then continues to cycle from NREM2 to NREM4 to NREM 2 to REM and back.

The first half of sleep is dominated by NREM4 (slow delta waves), with less REM (beta/alpha waves), whilst the second half of sleep is dominated by REM, with less NREM4.  Thus, some people argue that the first half of sleep is focused on physical repair and the second half of sleep is dominated by psychological/cognitive repair.

Your Sleep Architecture

Unfortunately, a number of common factors can prevent the normal sleep architecture.

What stops people reaching NREM4?

Caffeine, stress, sugar, light and certain hormones can all prevent a person from accessing NREM4.  When this happens, the normal regulation of hormones and physical repair does not occur.  This can lead to an excess of hormones that stimulate hunger and fat storage, and a decrease in the number of hormones that burn fat, balance blood sugar and stimulate the immune system.  At the same time, the lack of physical repair means that the person wakes up feeling tired and drained.

Affects of poor sleep

There are a number of side affects from poor sleep health.

With regards to weight, we know that poor sleep can lead to an increase in a person’s body fat level.  For example, poor sleep quality increases the level of ghrelin, a substance that stimulates hunger.  In particular, Ghrelin increases our cravings for refined foods and sugars, which lead to higher fat levels.  Also, poor sleep quality reduces impairs the hormone leptin.  The level of leptin in our body tells our brain how much fat we have.  When the body cannot sense Leptin, which is what happens when we have poor sleep, the body senses that we do not have enough fat and therefore increases our hunger and the level of fat-storing hormones.

Reduced sleep also impairs our immune cells.  Because the immune system is a key part in cancer prevention, a reduced immune system may increase our risk of certain cancers.

Finally, poor sleep health impairs our ability to control blood sugar levels.  In fact, just a few nights of less than four hours sleep can cause a person to enter a pre-diabetic state.  Poor sleep also impacts on our cardiovascular system, such as pushing up blood pressure.

Strategies to Improve Sleep

Avoid Stimulants
Stimulants are known to have a very significant impact on sleep health by interfering with out ability to enter deep sleep.

Caffeine, which is found in coffee, fizzy drinks, tea and some medications has a half life of five hours.  This means that 10 hours after having a coffee, there is still some left in your blood.  Imagine the effect on your sleep after drinking just a few cups of coffee each day!

Nicotine is also a potent stimulant.  Whilst many people feel that cigarettes help them feel relaxed, they actually have a secondary stimulant effect on the body. 

Because of the effect they have on our bodies, caffeine and nicotine are both addictive and so people need to consume more to achieve the same level of relaxation, leading to a net effect whereby people feel tense, anxious and stressed simply because of the craving for nicotine and caffeine.

Avoid bright lights before bed
Bright and flickering lights both send false signals into the “body clock” in our brain, telling it that it is daytime and that we should therefore be awake, full of energy and hungry for food.  This is often a common reason why people get cravings for refined and sugary carbohydrates at night.

Avoid electrical devices in the bedroom
Finally, because much of our body is controlled via electrical currents, there is some evidence that electrical devices may interfere with the way our body works.  This means that electromagnetic waves from electrical devices may affect our ability to enter deep sleep.

Eat foods rich in Tryptophan
There are also a number of things you can do that may help you sleep.

One of the best strategies is to try to eat foods that are rich in the nutrient tryptophan.  Tryptophan is an amino acid that is required in the body to produce serotonin, which helps us to relax and puts us to sleep.

There are a number of foods that are rich in tryptophan, including cheese and milk, turkey and chicken, and potato skin.  Other sources include dark chocolate, oats, bananas, dried dates and peanuts.  Unfortunately, simply eating these foods may not necessarily help.  This is because the body takes up other amino acids before tryptophan.  Therefore, you should try to have tryptophan-rich foods separately from other protein-rich foods (such as other meats).  Also, eating carbohydrate at the same time may help, because it helps move the tryptophan into the brain, where it is converted into serotonin.

So, a turkey or cheese sandwich on wholegrain bread, or jacket potato with chicken, may be a helpful evening meal.

Take a warm bath or shower before bed
Taking a bath or exercising gently before bed is an effective way of putting you into a sleepy state.  During sleep, the body’s temperature naturally drops.  This is a signal to the body to stay asleep.

When you have a warm bath or exercise gently before sleep, your body’s temperature rises.  When you then get out of the bath or stop exercising, your body temperature drops and this acts as a very strong signal that you should be asleep.

Build a night time routine
Human’s are creatures of habit and function best when following a routine.

With sleep, one key routine is the time that a person falls asleep and the time that they wake up.  There is evidence to suggest that the optimal time to fall asleep is 10.30pm, whilst the optimal time to wake up is 6.00am.  Ideally, try to follow both of these.  If you can’t follow both, then try to always wake up at the same time each day.

Another obvious tactic when trying to build a routine is to ensure that your brain associates the bedroom with sleep only.  Spending time reading and watching TV in the bedroom reinforces to the brain that you should be awake in the bedroom. 

If you only use the bedroom for sleep, you reinforce to the brain that you should be sleepy whenever you are there.

Try relaxation activities such as meditation or yoga
Relaxation activities are very good for stimulating the part of our body that aids rest and relaxation.  When this part of our body switches on, it is easier for us to switch off and sleep.

Classic forms of relaxation exercises include deep breathing meditation and Yoga and Tai Chi.

Avoid high intensity exercise before bed
Whilst moderate exercise can help our body’s to relax, high intensity exercise that lifts our heart rate above 85% of the maximum level actually stimulates the production of adrenaline and cortisol.  Both of these are energising hormones.  Whilst the effects of adrenaline are fairly short-lived in the body, the effects of cortisol can last for five hours or more.

When you are trying to fall asleep, the last thing you want is elevated cortisol levels, because it energises the body and therefore makes sleep harder to achieve.

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