Sleeplessness – we’ve all been there. It’s not a good feeling to lie awake at night, staring at the ceiling. Even though it’s late and you have to get up early, you just don’t feel tired. You wonder if you’re ever going to fall asleep.
Well, you may not realize it, but the reason you can’t sleep could be down to your eating and drinking habits. In particular, anything containing caffeine. Although you might only associate caffeine with coffee, it’s hiding in all sorts of things. If you consume caffeine soon before bed, it can severely affect your sleep.
Many of us enjoy a coffee after a late night meal without thinking about the effects it might have. But are you damaging your body by drinking coffee before sleep? When is the latest time that you should consume caffeine? And what should you do if you’ve had too much caffeine and can’t sleep?
Read on to discover the answers to all of these questions and more.
What is Caffeine?
Table of Contents:
- 1 What is Caffeine?
- 1.1 Which Products Contain Caffeine?
- 1.2 What Are the Effects of Caffeine?
- 1.3 How Long Does Caffeine Affect The Body?
- 1.4 Does Caffeine Affect Everybody the Same?
- 1.5 Does Black Tea Affect Sleep?
- 1.6 Does Decaffeinated Coffee Cause Sleeplessness?
- 1.7 What is the Latest Time to Drink Coffee Before Bed?
- 1.8 Is Caffeine Causing Your Sleeplessness?
- 1.9 How Does Caffeine Affect Sleep Quality?
- 1.10 How to Drink Coffee and Sleep Well
- 1.11 What if I’ve Had Too Much Caffeine before Bed?
- 1.12 What Else Could Be Causing Your Sleeplessness?
We’ve all heard of caffeine, but what exactly is it? It may surprise you to hear that caffeine is a psychoactive drug. Simply put, this means a chemical which changes the function of the brain.
Although it might sound scary, caffeine isn’t dangerous to most people if consumed in moderation. It’s a stimulant, which means it affects our body’s energy levels.
Most people consume caffeine to help them stay awake. A lot of the time, though, we consume caffeine without even knowing it.
Caffeine is a natural substance that is found in many types of plant. It’s possible for scientists to synthesize caffeine, but man-made caffeine isn’t normally used in products we buy.
This is because it’s so abundant in nature that there’s no need. In fact, we know of around 60 different plants around the world that contain caffeine.
The most well-known source of caffeine is, of course, coffee. There are two main kinds of coffee plant – coffea arabica and coffea canephora. They both contain caffeine in the seeds (more commonly known as coffee beans).
Caffeine is also found in the leaves of the tea plant. The kola nut – where the flavoring from cola comes from – also contains caffeine, not to mention exotic plants like guarana and yerba mate.
The Food and Drug Administration (FDA) advises a limit of 400 milligrams of caffeine a day for adults. That equals around four to five regular cups of coffee. Any more than that could result in health problems in the short and long term.
Which Products Contain Caffeine?
The most popular product containing caffeine is coffee. Humans have been drinking coffee since the 15th century. Nowadays, there are many different types of coffee including instant, filter, and espresso.
Along with coffee itself, most coffee-flavored products also contain caffeine. This could include coffee cakes, coffee liqueurs, coffee-flavored candies and more.
Tea also contains caffeine. Interestingly, tea leaves contain more caffeine than coffee beans, weight for weight. However, tea has to be diluted more than coffee does before drinking. As a result, tea ends up containing less caffeine than coffee per ounce.
There’s around 50 – 70mg of caffeine per cup of tea, compared to 100 – 150mg in coffee. Contrary to popular belief, green tea isn’t caffeine-free, either. It contains around 30mg of caffeine per cup.
Many soft drinks also contain caffeine. The most popular are sodas such as Coke, Pepsi, and Mountain Dew. Along with sodas, energy drinks also contain a substantial amount of caffeine. Red Bull, Monster, NOS, and Rockstar are all well-known brands.
Chocolate is also a source of caffeine. Generally speaking, the higher the cocoa content, the more caffeine there will be. Some bars of dark chocolate contains as much caffeine as a can of coke. Of course, this also means that most things flavored with chocolate contain caffeine. Watch out for the chocolate ice cream!
It’s not just food and drink that contains caffeine – you can also find it in many different medications and supplements. Always check the label if you aren’t sure.
What Are the Effects of Caffeine?
Caffeine is a central nervous system stimulant. In the short term, caffeine increases your blood pressure and your heart rate. It also constricts your blood vessels and tells the liver to release more sugar into your bloodstream. The main result of all of this stimulation is alertness.
Caffeine doesn’t provide your body with real energy, but it creates the sensation of it. So if you ingest caffeine too soon before bed, it can stop you from feeling tired. This is why you might find that you can’t sleep after an energy drink.
Caffeine is also a diuretic, meaning it dehydrates you. Consuming caffeine causes your body to let go of water, so you’ll urinate more at night. It’s important to drink more water to make up for it.
It’s important not to consume caffeine too regularly. If you have it too often, it can result in a physical dependence – otherwise known as addiction.
Taking away caffeine once you’re addicted can cause withdrawal symptoms. The most well-known caffeine withdrawal symptom is a bad headache. Other symptoms include irritability, drowsiness, and nausea.
In the longer-term, caffeine can have some quite undesirable effects. Regularly consuming more than the recommended amount can result in anxiety, insomnia, tremors and stomach problems.
Caffeine also creates a strain on the cardiovascular system. However, it’s not all bad news. Caffeine is an antioxidant, which means it could deter some cancers and heart disease. It’s also associated with a lower risk of developing type two diabetes.
How Long Does Caffeine Affect The Body?
So, now you know what caffeine is, and how it affects your body. The question is: how long do its effects last? To determine the answer to this, we need to look at how the body processes caffeine.
When you drink coffee, the caffeine enters your bloodstream through the lining of your mouth. It also seeps into your blood through your esophagus and stomach when you swallow. 45 minutes after drinking your coffee, 99% of the caffeine is already absorbed.
Once absorbed, your liver starts to metabolize the caffeine. It turns it into different chemicals called theobromine, paraxanthine, and theophylline. These chemicals travel around the body, affecting the various organs and body functions.
Now that the caffeine is working its way through your body how long until it leaves the system? The average half-life of caffeine is five to six hours. Let’s say you drink a small cup of coffee (100mg of caffeine) at 9 am. At 2 pm, about 50mg would be left in your system.
But the more you consume, the longer it takes for your body to be able to clear it. A Starbucks Venti Cold Brew Latte contains 276mg of caffeine. If you had one of those at midday, you’d still have 138mg in your system at 5 pm. It would be like drinking a regular sized coffee at 5 pm.
And how long does it take for the caffeine to leave your system entirely? According to scientific studies, it takes around 27.6 hours for there to be no trace left. Remarkably, that’s over a day.
Does Caffeine Affect Everybody the Same?
As a general rule, caffeine makes most people feel energized and awake. Even though caffeine doesn’t provide the body with energy, it creates the same sensation as if you’d had some extra sleep.
Why is this? Your brain creates the neurotransmitter adenosine when it recognizes the need to sleep. Adenosine binds to special receptors in nerve cells, which slows down the cell’s activity and makes you feel tired.
If caffeine is in the system, the caffeine binds to the adenosine receptors instead. But it doesn’t slow down the cell activity. Your body is still suffering from a lack of energy, but because the adenosine can’t communicate this to your nerve cells, you feel awake and alert.
However, caffeine doesn’t affect everybody the same. Scientists have identified a gene, called CYP1A2, which has two different variants. If you have the 1F allele, you metabolize caffeine slowly.
This means that it affects you for longer, and takes a longer time for the caffeine to leave your system. However, if you have the 1A allele, you metabolize caffeine far more quickly. People with this allele may not feel any effects of caffeine, because their body gets rid of it before they consciously feel the effects.
It’s also possible to become tolerant of caffeine. If you drink caffeine regularly, you’ll eventually need more and more to feel awake. Interestingly, younger people also seem to be less sensitive to caffeine than older people.
Does Black Tea Affect Sleep?
By now, we know that drinking coffee and energy drinks before sleep is a bad idea. Because it stops you from feeling tired, you’ll have a hard time trying to fall asleep after drinking coffee.
But what about black tea? Many people don’t realize that black tea also contains caffeine. In some cultures, having a cup of tea to wind down before bed is an accepted tradition. But is this hampering your ability to sleep?
If you measure the caffeine content of dry tea leaves and coffee beans, there’s more caffeine in black tea than in coffee. On average, there’s around 30mg of caffeine per gram of black tea. By contrast, one gram of coffee grounds has roughly 12mg of caffeine.
However, it’s not all about the dry weight. When you make a cup of tea, a lot of water is added to dilute the taste of the leaves (which are then discarded). Coffee is not diluted as much as tea, which is why a cup of coffee contains more caffeine than a cup of tea.
On average, a cup of tea contains about half the caffeine of a cup of coffee (as long as the cups are the same size). However, each cup of tea is different.
The longer you steep the tea, the more caffeine is infused into the water. If you have your tea very weak, you’re probably going to be ok before bed. On the other hand, if you drink two cups of strong tea, it’s going to have the same effect as a cup of coffee.
Does Decaffeinated Coffee Cause Sleeplessness?
While coffee has been around for at least 600 years, decaffeinated coffee is a relatively modern invention. Manufacturers use substances such as water, activated charcoal, and carbon dioxide to remove the caffeine from coffee beans. The beans retain most of their coffee flavor.
Interestingly, though, its name is a bit deceiving. Contrary to popular belief, decaffeinated coffee isn’t caffeine-free. As hard as they try to remove all of the caffeine, some remains left over. On average, the decaffeination process removes 94% to 98% of the caffeine from coffee.
So, while a normal cup of coffee might contain 100mg of caffeine, a cup of decaf coffee contains around 5mg. It’s not much, but it’s not zero either. Scientists believe that drinking 5 cups of decaf coffee could be enough to feel the effects of caffeine. If you drank 10 cups, it would be equivalent of drinking a small cup of normal coffee.
Of course, you’re very unlikely to drink 10 cups of decaffeinated coffee before bed. So in most circumstances, you can have a cup or two of decaf and not worry too much.
However, some people are advised by doctors not to consume caffeine for medical reasons. This includes people with a kidney problem and anxiety disorders. If you’ve been told not to consume caffeine at all, it’s best to avoid decaf coffee and tea altogether.
What is the Latest Time to Drink Coffee Before Bed?
So, if you enjoy drinking coffee but you don’t want it to affect your sleep, how can you make sure it doesn’t? The best way is to figure out what time of day you should have your last cup without it affecting your sleep.
Many people choose to drink coffee in the morning, as soon as they get up. If you frequently feel groggy when you wake up, this could be you. Caffeine gives you that buzz of alertness that you need in the morning. Fortunately, coffee drank over breakfast will wear off long before you go to sleep.
However, if you indulge in a Starbucks during the afternoon, you could be cutting it fine. A study conducted by sleep scientists tested how caffeine affects sleep when consumed at different times. They found that caffeine consumed up to 6 hours before bedtime had a significant effect on sleep quality.
Participants who drank caffeine 6 hours before bed (and later) spent a lot of time awake at night. When they did get some sleep, it was bad quality. Compared to people they studied who didn’t consume caffeine, there was a big difference.
So, what does this mean? Subtract 7 hours from your bedtime, and don’t drink coffee after that point. For example, if you go to bed at 11 pm, the worst time to drink coffee is after 4 pm. To be on the safe side, many doctors recommend not drinking coffee after 2 pm, as a general rule.
Is Caffeine Causing Your Sleeplessness?
If you’re suffering from poor quality sleep, caffeine could be your problem. Studies have found that caffeine continues affecting your body long after you stop feeling it. So even once the buzz has worn off, your coffee habit could still be hurting your sleep.
It’s time to look at your caffeine habits to see if they might be affecting your sleep. First of all, make a list of every food and drink you consume after lunchtime. Check to see if any of them contain caffeine.
In particular, look out for:
- Coffee, and coffee-flavored foods
- Black, green and white tea
- Energy drinks and sodas, even “diet” or “sugar-free” versions
- Chocolate, and chocolate-flavored food or drink
- Candies, including some breath mints
- Protein bars and energy bars
If you’re unsure, always check the package, or contact the manufacturer. You might be surprised which products contain caffeine.
Also, take a look at any medications you’re on. Some, particularly pain-killing and migraine medications, can contain caffeine. This is because caffeine also works as a vasoconstrictor, making your blood vessels narrower.
Headaches and migraines happen when the blood vessels in the brain widen. If at all possible, avoid medications containing caffeine after 2 pm. Ask your doctor or pharmacist if there are any alternatives which don’t contain caffeine.
Interestingly, some weight loss pills and products also contain caffeine. So if you use any of those, check the packaging to be sure.
How Does Caffeine Affect Sleep Quality?
We’ve established that it’s best not to drink caffeine too soon before bed. But, how does caffeine affect the quality of our sleep?
Firstly, it makes it difficult for you to fall asleep. Caffeine poses as adenosine, the chemical that your brain releases to tell your body it’s tired. When caffeine has bound itself to adenosine receptors, the real chemical can’t get in. The result?
Even though you’re low on energy, you don’t feel tired. And when you try to fall asleep, you can’t switch off. This means that you’ll end up getting less sleep, and feel tired in the morning.
When you finally manage to fall asleep, caffeine can still have an effect. If there’s still caffeine in your system while you sleep, you’re more likely to wake up during the night. You’ll find yourself sleeping very lightly, and waking up for seemingly no reason.
Because of this, caffeine has a detrimental effect on your sleep cycle. When you sleep, your brain naturally cycles through light sleep, deep sleep, and REM sleep. If you’re always waking up, the cycle resets. For this reason, there’s a link between caffeine and REM sleep, and caffeine and deep sleep. Drinking caffeine before bed means you could miss out on these two vital sleep stages.
Missing out on deep sleep and REM sleep can severely affect your health. You may wake up feeling groggy, sleepy and disoriented most days. You might also have problems with concentrating and thinking. Tasks which should be easy will feel a lot harder than they should. You may even experience mood changes or mild hallucinations.
How to Drink Coffee and Sleep Well
Sleep is extremely important for our physical and mental wellbeing. Getting at least 7.5 hours of quality sleep per night can even increase the length of your life. But if you’re a coffee lover, you probably won’t like the idea of giving it up altogether.
So, what’s the best way to drink coffee and still sleep well at night? Firstly, maintain a proper sleep schedule. Aim to go to bed and wake up at the same time every day, including weekends. This way, your body will get used to when it should be sleeping. It also makes it easier to avoid accidentally drinking coffee too close to bedtime.
You should try to say no to caffeine after 2 pm. Sometimes, though, it’s not that easy – especially if you’ve formed a habit. One way to make it easier is to switch to a different hot drink. Certain teas, like fruit teas, contain very little caffeine. Hot chocolate is another good option – there’s only around 5 – 15mg of caffeine in every cup.
If what you crave is the coffee flavor, try switching to decaffeinated coffee. Most good quality brands taste very similar to regular coffee. Although they aren’t wholly caffeine-free, having one or two cups won’t do you any harm.
Remember to limit your intake to 400mg of caffeine per day, no matter what time of day you consume it. If you must have your four coffees every morning, try switching to a smaller cup.
What if I’ve Had Too Much Caffeine before Bed?
If you’ve accidentally consumed caffeine too close to bedtime, don’t worry. One night of poor sleep won’t have too much of a toll on your health. You might feel groggy and miserable tomorrow, but the effects won’t last long.
To induce tiredness, try taking a long, relaxing bath. Gently increasing your body temperature before bed can help you to feel sleepy. Don’t make the water too hot, as extreme heat can make it difficult to sleep. The water should be comfortably warm.
You can also try listening to calming, instrumental music. Avoid anything with words, as that can keep the language processing part of your brain active. Try to find music with a slow beat, as this can reduce your heart rate. White noise or nature sounds can also help with relaxing.
Make sure your bedroom is quiet, dark, and cool. Use blackout blinds if necessary, to keep out any light from the outside. Set your thermostat to a comfortable, cool temperature, as it’s harder to sleep in warm conditions. Also, avoid using any electronics or devices with a screen before bed. The blue light from screens can trick your brain into thinking it’s daytime.
There is some evidence to suggest that lavender essential oil can also be sleep-inducing. You could try lavender-scented candles, diffusers or wax melts. You could even try putting a few drops of lavender essential oil on your bedding.
If you still can’t sleep, you may just need to wait for the caffeine to wear off. Sometimes, sadly, time is the only cure.
What Else Could Be Causing Your Sleeplessness?
If you follow all of the above advice, you should be sleeping well in no time. You should now recognize which foods and drinks contain caffeine, and know to avoid them after 2 pm. You should also know how to create a good sleeping environment and schedule.
After all of this advice, if you’re still struggling to sleep, you might have a different problem. Insomnia – the inability to fall asleep or stay asleep at night – can have many different causes.
One of the main causes of insomnia is poor mental health. If you think you might be suffering from depression, anxiety or stress, speak to your doctor. These conditions can make it difficult to sleep, but there are medications and therapies which can help.
If you are on any medication, read the label thoroughly. Some medications can interfere with sleep. If this is the case, it should be listed as a side effect. Speak to your doctor to see if you can switch to a different medication.
If you drink alcohol before bed, this may also be causing a problem. Many people find alcohol relaxing, but it impairs sleep quality. So although you may fall asleep faster, you won’t get as much good quality rest.
Finally, don’t eat heavy meals, sugary or starchy foods too close to bedtime. Eating provides your body with energy, so it may make it more difficult to fall asleep. Aim to avoid all food 3 hours before bedtime.
If none of the above apply to you, there might be a less obvious cause for your sleeplessness. Arrange an appointment with your doctor, and they’ll be able to help investigate the cause.