Caffeine & Sleep
“Caffeine is the most widely used (and abused) psychoactive stimulant in the world.” (Walker, Why We Sleep, 2017)
Introduction
80% of the world’s population consume caffeine in one form or another and coffee is the second most traded substance in the world, second only to oil. Our love affair with caffeine stretches around the globe and has done for centuries. Most people will have a basic understanding that caffeine has a negative effect on sleep, but this blog post has been written to better inform readers about how caffeine works and to try to help individuals reassess their current “need” for caffeine.
Before I begin I would just like to clarify that I am not judging anyone for their use of caffeine. This blog post is not an attempt to guilt you into giving up something that you enjoy. What it is asking you to do is to reassess your current use and the reasons why you use caffeine. If you actually “need” caffeine to get you through the day then you should probably come clean and admit to yourself why. Mostly people use caffeine to bolster low energy levels and they have low energy levels because they have not slept well enough or for long enough the night before. If this is the case for you then I would recommend that you sort out your sleep issues first rather than simply papering over the cracks with another cup of coffee.
What is caffeine?
Caffeine is a psychoactive drug classified as a stimulant because it speeds up the central nervous system and increases neural activity in the brain. Other psychoactive stimulant drugs include amphetamine (speed), cocaine and nicotine.
Caffeine is a naturally occurring chemical present in cocoa, coffee, cola and most teas. Below I have listed the most common foods and drinks that contain caffeine and their caffeine content. For the sake of easy comparison, I have adjusted them so that they are all per 100ml or 100gm. However, please remember that we do not always consume 100ml/gm of a product and therefore the amount of caffeine you are ingesting will vary depending on the size of the mug/chocolate bar/can etc. For example, a Starbucks Grande coffee is nearly half a litre (473ml) and contains 330mg of caffeine!
Interesting Fact
Plants use caffeine as a natural pesticide as it is highly toxic to most insects.
It is also worth noting that the caffeine content of tea and coffee will vary greatly depending on how long you leave the drink to brew. In the table below, the tea was left to brew for one minute. If you prefer a stronger cup, the amount of caffeine in that drink will be higher.
| Product | Caffeine Content per 100gm/ml |
|---|---|
| Instant Coffee | 26mg |
| Brewed Coffee | 40mg |
| Iced Coffee | 40mg |
| Decaf Instant Coffee | 10mg |
| Decaf Brewed Coffee | 13mg |
| Espresso Coffee | 213mg |
| Tea (English Breakfast) | 20mg |
| Decaf Tea | 5mg |
| Green Tea | 12mg |
| Hot Chocolate | 2mg |
| Cola | 9mg |
| Sugar Free Cola | 15mg |
| Red Bull | 30mg |
| Dark Chocolate | 80mg |
| Milk Chocolate | 20mg |
| White Chocolate | 0 |
| Chocolate Coated Coffee Beans | 869mg |
| Pro-Plus | 100mg |
| Panadol Painkillers | 13mg |
Please also remember that all products that contain coffee or coffee flavouring will contain caffeine, including coffee flavoured ice cream, coffee cake, tiramisu etc. I once spent a very frustrated night wide awake at 2am after eating a single slice of tiramisu - a mistake I will never make again!
Interesting Fact
Sugar-free colas contain more caffeine than standard cola. I wonder whether this is to compensate for the lack of a sugar rush when drinking it?!
There are other ingredients available to the food industry that act as stimulants similar to caffeine that will also have an impact on your sleep. Keep an eye out for any product that contains ginseng, guarana or taurine.
Effects of caffeine use
Caffeine is known to have the following effects on the body and mind…
Dehydration
Depleted vital nutrients
Adrenal fatigue
Anxiety and panic attacks
Insomnia
Migraine
IBS
Stomach ulcers
Diarrhoea
Muscle loss
Increased heart rate and palpitations
Increased blood pressure
Bladder issues (including urge-incontinence)
Exacerbation of sensitive skin issues, such as rosacea
Hormonal imbalances
However, it’s not all bad news. Caffeine is now added to a variety of different painkilling medications for a couple of reasons. Firstly, by increasing your blood pressure, caffeine ensures that any other pain medication is transported to the area affected and gets to work quicker than if you take those substances alone. Caffeine can also reduce inflammation and block the perception of pain in the brain.
There have been some studies that suggest that taking onboard some caffeine prior to a work out will mean that you will burn more calories during the work out and may experience higher levels of endurance. Caffeine may also delay the onset of multiple sclerosis, Alzheimer’s and Parkinson’s and aids in the release of dopamine, which is one of our feel-good hormones.
Caffeine is sometimes claimed to be useful to help the body detoxify. This is because caffeine is not only a stimulant but also a diuretic. A diuretic stimulates the production of urine which is our natural means of removing toxins from our system. However, in doing so, caffeine not only irritates our bladder but can also cause dehydration by stimulating us to pass excessive water that is vital to our body.
Confusing but true!
Caffeine applied directly to the skin has completely different properties than when ingested. Some treatment creams designed for over-stimulated skin (sensitive, rosacea) contain caffeine as it helps to calm the area.
How much caffeine is too much?
Recommended daily caffeine intake…
Healthy Adults: 300-400mg per day
Pregnant Adults: 100-200mg per day
Adults with Heart Problems: 100-200mg per day
16-18 year olds: 100mg per day
Children under 16: NONE!!!!!!!
As with other stimulants (i.e. amphetamine, cocaine etc) if a person uses them enough, not only do they build up tolerance so that they need to use more to get the same effect from them, they will also experience withdrawal symptoms if they do not feed their habit.
If you find that you get less and less of a positive effect from caffeine the more you ingest, then there are two possible reasons for this. The first is that your body has simply become used to a certain level of caffeine in your system and can therefore tolerate higher doses with no significant impact on your bodily functions. This is truly a caffeine addiction and will also be characterised by withdrawal symptoms if you do not keep your caffeine levels adequately topped up.
The second reason is related to your adrenal glands - the glands in your body that produce the stress hormones adrenaline and cortisol. If you are living with constant high levels of stress then your adrenal glands will naturally become fatigued through overwork. Caffeine also stimulates your adrenal glands to produce cortisol and therefore if you consume too much caffeine it can cause burnout of the glands. The glands then become weakened and respond inadequately to future hits of caffeine, rendering your morning coffee almost negligible.
Caffeine withdrawal is now a recognised medical condition, the symptoms of which include headaches, lethargy, sleepiness, irritability, constipation, depression, muscle pain/stiffness/cramping, lack of concentration, flu-like symptoms, insomnia, nausea, vomiting, anxiety, brain fog, dizziness, low blood pressure and heart palpitations. Caffeine withdrawal symptoms can last from two days to two weeks for light users and up to two months for previously heavy users.
Further Reading
If you would like more information about caffeine withdrawal or would like to complete a quiz to find out how addicted you are to caffeine, go to…..https://www.caffeineinformer.com
What does this have to do with sleep?
To understand why caffeine has such a devastating impact on sleep it is important to understand what happens in our body when we ingest it. In a previous blog post I described how the process of sleep pressure works, but for anyone who has missed it, put simply, sleep pressure builds up and up from the time of your last awakening in the same way as hunger builds up since the last time you ate.
Caffeine artificially mutes or blocks the effects of sleep pressure (by blocking the adenosine receptors) so that you no longer experience the sensations of feeling tired. Contrary to popular opinion, caffeine does not magically give you more energy or actually make you less tired, it simply tricks you into putting those feelings aside while you are under its influence. However, as soon as the caffeine leaves your body you will feel just as, if not more, tired than you did before. This is due to increased sleep pressure built up over the time you had caffeine in your system, but also to the chemical/biological phenomenon of rebound. In fact, for heavy caffeine users, if the body is allowed to finally purge itself of all caffeine, the huge rebound wave of tiredness that follows can be unbearable.
The effects of caffeine peak 20 to 30 minutes after ingestion and, in the average person, the toxin is eliminated from your system in between 4 and 8 hours. This means that any of both the positive and negative effects of caffeine will be present for up to 8 hours after it was last ingested.
Caffeine is broken down (like most toxins) in the liver by a specific enzyme (CYP1A2 - catchy name!). The amount of that specific enzyme present in the body varies between individuals, which means that some people are more sensitive to the effects of caffeine and some find the effects of caffeine are longer lasting than others . However, we all see a reduction in the effectiveness of that enzyme over time, so that as we get older we become more and more sensitive to the effects of caffeine and it takes our bodies longer and longer to process. You may find therefore that the negative impact caffeine has on your sleep (and other bodily functions) increases with age. Your body’s ability to remove caffeine is also slowed during pregnancy.
Interesting Fact
Nicotine, grapefruit juice and the contraceptive pill can all inhibit the liver’s ability to detoxify caffeine from the system.
When we try to sleep with caffeine in our blood stream it takes us longer to fall asleep and our sleep cycles are shallow, interrupted and fragmented. This means that we lie awake longer in our bed than we would do normally either at the start of the night or throughout the night, or both. Overall it decreases the total time that you are asleep and drastically lowers the percentage of that time that you spend in slow wave or deep sleep. Caffeine has also been reported to impair the subjective quality of sleep (how well individuals feel they are rested on awakening).
However, it is very common for caffeine users to miss the clues and underestimate the effects of caffeine on their sleep or to attribute their poor sleep or lack of energy to another source.
“….caffeine disturbs objective sleep parameters (indicators) even in those who subjectively claim that it has no impact on theirs” (Morin, 1976)
Unfortunately those people who do sleep with residual caffeine in their system are much more likely to wake up the following morning and complain that they are still tired or lacking in energy. And what is the first thing that we tend to do after a poor night’s sleep?…..reach for a strong cup of coffee! In this way it is easy to see how people get caught in a cycle of bad sleep and caffeine dependence.
So why do we still continue to use caffeine at all?
When I recommend to my clients that they reduce or abstain from caffeine consumption they generally give me one of the following reasons for wanting to continue their use. Again, I would like to state that, although I am very strict at limiting my caffeine consumption, I will happily admit that I am totally addicted to sugar and have no right to judge!
But I really enjoy a cup of coffee/tea
If you feel as though you don’t actually need caffeine but enjoy a coffee, maybe once a day or in a social setting, the suggestion is that you simply take into account when you consume. The advice is to avoid it 8 hours before bed and that you don’t have that one coffee immediately after waking up in the morning.
But I need caffeine in order to wake up in the morning!
Whether you are a caffeine user or not, when we first wake up in the morning, especially if you have been woken up by an alarm mid way through your sleep cycle, we initially feel a little groggy, even if we have had eight hours of good quality sleep the night before. This is called sleep inertia, which is completely normal and will go away naturally with a little time. However, as previously discussed, if you have slept with residual caffeine in your system you may find that your sleep inertia lasts slightly longer, which can tempt you to reach for a coffee first thing.
If you drink your coffee at this point, the caffeine will drag you out of the sleep inertia so that you are feeling “normal”, but no more than that. My advice is that you wait until your sleep inertia has passed before you have your coffee and that way you will get much more bang for your buck!
For individuals who continue to consume caffeine in the evening there may also be another influential factor. As discussed earlier, once your body has finally removed all caffeine from your system, you may experience a great flood of tiredness and if this happens first thing in the morning you will more than likely feel that you couldn’t possibly make it through the day without your caffeine hit.
But I’m irritable without my morning cuppa!
If you are a regular caffeine user you may well be suffering from caffeine withdrawal first thing in the morning. Common symptoms of overnight caffeine withdrawal is waking up with a headache, feeling irritable and experiencing brain fog.
But caffeine makes me more productive at work
For anyone who claims that they “need” caffeine in order to focus their mind and function properly for their job I would just like to show the results of a scientific experiment conducted on spiders by NASA in 1995.
In a controlled environment, scientists gave spiders minute samples of several different psychoactive drugs, including caffeine, and then observed the webs that they built whilst under the influence. As you can see from the diagrams below, caffeine may well stave off any lethargy so that a web is built but the quality of the web is highly-questionable…..and let’s face it, the spider would have built the web anyway, with or without the caffeine.
If you need a good laugh today, check out the comedy version of the results of this experiment on YouTube. Just search for 'spiders on drugs’ and enjoy!
Caffeine is only a short term, quick fix for lethargy and, although may increase your productivity, will probably not improve the quality of that work. If you are looking for something that boosts your work performance by increasing your productivity, analytical skills, creativity and your relationships with your colleagues, look no further than getting a good night’s sleep. Caffeine and the potential for creating sleep deprivation may actually be the cause of your problem rather than the solution.
But caffeine helps me deal with stress
As caffeine is a stimulant you may well be fooled into thinking that by making you more alert you are therefore more ready to cope with stressful situations, but scientific research has proved this not to be the case. In a small study of habitual coffee drinkers, it was found that caffeine actually amplifies the stress response by mimicking the physiological effects of stress, i.e. increased heart rate, increased blood pressure and the production of cortisol.
But I only drink decaffeinated products
One of the biggest myths surrounding caffeine is that decaffeinated products are totally caffeine free. Unfortunately de-caff never means no-caff. In fact decaffeinated drinks can contain between 15% and 30% of the original caffeine content. This varies greatly and it is very difficult to know from packaging etc how efficient the decaffeination process has been for a particular product. It might also be worth noting that in a study of decaffeinated drinks in a variety of different coffee shops in the UK, one in three were actually made with standard coffee and passed off as decaffeinated!
The other problem with consuming decaffeinated products is that the chemical process undertaken to reduce the naturally occurring caffeine from them is not particularly wholesome. Coffee, for example, is soaked in either methylene chloride (paint stripper) or ethyl acetate (nail varnish remover). Therefore, if you are wanting to eat “clean” and steer clear of noxious chemicals, you are probably better off sticking to naturally caffeine free products such as rooibos tea.
Interesting Fact
White chocolate is naturally caffeine free. This is because white chocolate is not really chocolate at all and doesn’t contain any of the caffeinated ingredient, cocoa.
But I only have caffeine in the morning?
In order for your sleep to not be interrupted by caffeine it is important to have no caffeine in your system when you get into bed. Therefore it would be sensible to stop your caffeine intake around 8 hours before bedtime. Switching to decaffeinated in this time period will help, but please remember that there is still some caffeine in decaffeinated products. You should also be aware that heavy caffeine use in the morning and then tailing off after lunch may produce daily withdrawal symptoms in the evening which can also inhibit sleep.
Conclusion
I hope you have found this blog post to be informative and helpful. If you would like more information or you have another reason for ingesting caffeine that I have not mentioned but is valid, please let me know. You can contact me via the button below.
If you believe that your caffeine use is interfering with your sleep pattern and you would like some help reducing or withdrawing completely from caffeine, get in touch now via the contact button below for some sleep coaching sessions.
Additional Reading
Sleep pressure - https://www.fromsoultosole.co.uk/sleep-pressure
Sleep cycles - https://www.fromsoultosole.co.uk/sleep-cycles
