This article was written and researched by Dr. Albert Stezin (MBBS, Ph.D – clinician and neuroscientist) to ensure maximum factual accuracy and unique content.
Unlike energy drinks that label their caffeine content, it’s typically quite difficult to find out exactly how much caffeine is in your coffee, and it’s even harder to work out how long each individual drink can keep you awake.
An 8oz cup of coffee typically contains around 100 mg of caffeine and will keep you awake for between 4 and 10 hours – with more sensitive individuals potentially needing more than 12 hours for the caffeine half-life to reduce to the point where sleep is possible.
This guideline means that it’s possible to work out how long different types of coffee drinks will keep you awake – which I’ve done for you in this article to save you the time and effort.
The Effects of 15 Coffee Drinks on Wakefulness
The highest concentration of caffeine in the blood is reached between 15 and 120 minutes after the intake of caffeine in the form of coffee.
To understand how long caffeine stays in the body after it is absorbed into the bloodstream, it is necessary to understand the terms “half-life” and “clearance”.
The half-life of a substance refers to the time it takes for the concentration of the substance to reduce to half of its original concentration.
When the concentration decreases in the blood, so do its effects on the body.
Clearance refers to the ability of the body to clear a substance from the blood through the kidneys, liver, and other tissues.
These factors are linked to each other.
As clearance increases, the half-life decreases, and vice-versa.
Sleep is Typically Possible Within 10 Hours of Consuming Coffee
In healthy individuals, the average half-life of caffeine is approximately 5 hours.
This means that the concentration of caffeine in the blood decreases by 50% every five hours.
With this drop in the concentration of the caffeine, the stimulant action also decreases.
According to sleep experts, a single half-life of caffeine (approximately 5 hours) would lead to a significant decline in the stimulant effects.
The table below documents the caffeine content of 15 common drinks/desserts and the approximate amount of time that they can keep you awake.
The wakefulness time will vary in reality due to individual tolerances and the other factors discussed later in this article, so I have provided an approximate range:
|Coffee Type||Caffeine Content||Approx. Wakefulness Time|
|Cold brew||205mg/16oz||8-12 hours|
|Espresso (single)||40-63mg/1oz||1.5-6 hours|
|Flat white||130mg/12oz||5-12 hours|
|Ristretto||33mg/20ml (0.67oz)||1-3 hours|
1: Espresso: 1.5 to 6 Hours of Wakefulness
The typical serving size of espresso (1oz/30ml) contains 40 to 63mg of caffeine, and a double shot (2oz/59.2ml), called a doppio, has 80 to 126mg.
To get to sleep no later than 10PM, you should have your last espresso by 4 PM, and your last doppio before lunchtime.
Espresso is made by using pressure to force hot water and steam through finely-ground coffee.
This causes the maximal extraction of caffeine, and makes espresso one of the most caffeine-rich coffee options.
It is for this reason that espresso has a much smaller serving size than other types of coffee.
2: Americano: 10-12 Hours of Wakefulness
An Americano consists of an espresso shot diluted with hot water.
A medium (12oz) Americano contains 249mg of caffeine.
In my opinion, your last Americano should be no later than midday if you want to get to sleep before 10PM.
3: Cortado: 5-12 Hours of Wakefulness
A cortado is a blend of espresso and warm steamed milk.
It usually uses a double shot of espresso, and contains 136mg of caffeine per 8oz (small serving).
As this is a high-caffeine beverage, you should refrain from drinking after midday if you want to sleep well by 10 PM.
4: Macchiato: 3.5-8.5 Hours of Wakefulness
The macchiato is an espresso-based drink with a small amount of foam.
A 2oz serving of macchiato contains 85mg of caffeine.
In order to get to sleep by 10PM, you should have your last macchiato before 1PM.
5: Mocha: 6-12 Hours of Wakefulness
The mocha is an espresso drink blended with chocolate, steamed milk, and foam.
A medium serving (12oz) of café mocha contains 152mg of caffeine.
Drink your last mocha at around lunchtime.
6: Ristretto: 1-3 Hours of Wakefulness
Ristretto is an espresso made with a little hot water, and has a sweet flavor.
The serving size of a ristretto is 20ml (0.67oz), and contains 33mg of caffeine.
Ristretto is extremely strong, but if you keep to a small serving size, you can have your last shot at 4 PM.
7: Flat White: 5-12 Hours of Wakefulness
This Australian concoction is either a cappuccino without the foam or chocolate sprinkle, or an espresso drink with steamed milk.
A 12oz serving of flat white contains 130mg of caffeine, and should be consumed before lunch time.
8: Affogato: 2.5-8.5 Hours of Wakefulness
The affogato is a shot of espresso with a scoop of ice cream, and contains 65 to 85 milligrams of caffeine per dessert.
In general, espresso-based drinks have a higher caffeine content, and would need at least 1 to 2 half-lives for the caffeine content to drop to less than 50mg.
If you are partial to espresso-based beverages, I recommend that you have your last drink at least 8-12 hours before your bedtime.
9: Latte: 3-8 Hours of Wakefulness
Latte is a variation of espresso with steamed milk and foam.
It is available either as a plain latte, or with additional flavors, such as vanilla or pumpkin spice.
Since it contains more water and milk, the caffeine content is usually much lower than for plain espresso.
A typical (12oz) serving contains 80mg, and should be consumed no later than 6PM if you tolerate caffeine well, or no later than 2PM if you are very sensitive to caffeine.
10: Cappuccino: 3-8 Hours of Wakefulness
Cappuccino is a type of latte made with foam, and sprinkled with cocoa powder and cinnamon.
Similar to a latte, a medium (12oz) cappuccino contains 80mg of caffeine, and should be consumed no later than 6PM if you aren’t affected too badly by caffeine, or no later than 2PM if you feel the effects of caffeine more strongly.
11: Galão: 2.5-6.5 Hours of Wakefulness
This Portuguese coffee is another variation on the latte, which has twice the amount of foamed milk.
It contains 65mg of caffeine per 8oz, and in general the last Galão of the day should be consumed no later than 4 and 6 hours before bed.
12: Cold Brew: 8-12 Hours of Wakefulness
A cold brew is made by steeping coffee beans for 36 hours, and then adding cold milk or cream.
A 16oz serving contains 205mg of caffeine.
Drink it after lunch at your own risk.
13: Frappuccino: 3-7 Hours of Wakefulness
A Frappuccino is made by blending iced coffee with whipped cream and syrup.
It contains 70mg of caffeine per 16oz serving.
If you tolerate caffeine well, then you may be able to drink a frappuccino 3-4 hours before bed, whilst more sensitive individuals should allow at least 7 hours.
14: Nitro: 8-12 Hours of Wakefulness
This has a frothy, Guinness-like consistency, and is a cold coffee brew with nitrogen bubbles.
A 16oz serving contains 205mg of caffeine.
Avoid Nitro after 2 PM.
15: Decaffeinated: <1 Hour of Wakefulness
Decaffeinated coffee, as the name suggests, has a low content of caffeine.
A single serving of decaffeinated espresso contains approximately 4mg of caffeine.
Decaffeinated coffee is the only type of coffee that can be consumed close to bedtime.
11 Factors That Influence the Wakefulness of Coffee
Many factors can affect the duration of the stimulant action of caffeine and therefore the length of time that coffee can keep you awake – 11 of the main ones are discussed below:
1: Genetics Can Affect Caffeine Metabolization
You may wonder what genetics has to do with coffee.
Well, recent studies show that specific gene variants can slow down or accelerate the removal of caffeine from the blood.
Furthermore, the genes that control the molecular targets of caffeine, such as the adenosine receptors, also show significant variation in the population.
These may lead to a longer duration, or a shorter period of action, and may lead to disruption of sleep after consumption of coffee.
Whilst you don’t need to go and get a genetic test, if you are one of those people who experiences short- or long-lasting effects from caffeine, be mindful of the quantity and timing of your consumption of coffee.
2: Greater Bodyweight Can Prolong the Stimulant Effect
Differences in body weight may alter the metabolization of caffeine.
There are clinical reports that suggest that people with higher body weight metabolize caffeine slower, and have a 31 to 69% prolongation of its half-life.
This effect is more commonly seen in women.
Hence, people with obesity – especially women – may have a longer stimulant action from caffeine, which may keep them awake at night, even after a single cup of coffee.
I recommend that people with a higher body weight avoid coffee after noon.
3: Extremes of Age Can Alter Caffeine Metabolization
Age, in its extremes, may affect caffeine metabolization – i.e., in children, and the elderly >71 years.
In these age groups, the clearance of caffeine is very slow, leading to prolonged stimulant action, and wakefulness.
Existing research data leads to the recommendation of abstinence from coffee in children and adolescents, and that people over the age of 70 years should avoid a “coffee-high”.
4: Pregnancy Increases the Duration of the Stimulant Effect
Pregnancy is a period of dynamic metabolic change.
Previous studies show that the half-life of caffeine is prolonged during the latter part of pregnancy (last 3 months), and returns to the normal level a week after delivery.
During this period, the half-life of caffeine may increase up to 18 hours.
Furthermore, caffeine accumulates in the mother and fetus, since metabolism is delayed significantly throughout the pregnancy period.
For this reason, I recommend avoiding coffee during the entire period of pregnancy.
5: Liver Diseases Are Bad News for Coffee Lovers
People with liver diseases, such as liver cirrhosis or liver failure, have a very slow metabolization of caffeine.
It is estimated that caffeine may stay in the blood for 50 to 160 hours during liver failure.
The prolonged half-life of caffeine would keep the brain stimulated for many days, during which sleep could be difficult to achieve.
If you have a liver disease, you should avoid coffee.
6: Smoking Can Go Either Way
Smoking stimulates caffeine removal from the body.
Studies show that cigarette smoking doubles the rate of clearance of caffeine.
This leads to a lower concentration, and a short half-life of caffeine in the blood.
Hence, smokers may never really feel the full stimulant effect of caffeine.
However, after cessation of smoking, the caffeine clearance slows down significantly, leading to a twofold increase in the blood levels of caffeine.
Upon continued consumption of coffee, caffeine concentration may even reach 203% of the patient’s baseline amount, causing an unopposed brain stimulation that will disturb sleep.
In my opinion, you should not smoke to get rid of caffeine in order to sleep faster, as nicotine in cigarettes has its own sleep-disrupting stimulant action on the brain.
Furthermore, if you are trying to quit smoking, you should abstain from coffee, and caffeine-laden foods and beverages, for some time.
7: Diet Can Affect Caffeine Metabolization
The contents of your diet can significantly affect the metabolization of caffeine.
Grapefruit juice is known to decreases caffeine clearance, and prolongs its half-life by 31%.
On the contrary, consumption of broccoli, cabbage, kale, etc. (cruciferous vegetables), and large quantities of vitamin C from citrus fruits, increases the caffeine clearance.
Vegetables like carrots, celery, parsley, caraway, and fennel – as well as South Asian diets, containing curcumin and turmeric – are known to decrease CYP1A2 activity (an enzyme that metabolizes caffeine), and prolong caffeine effects.
Thus, diets rich in the above foods can either decrease or increase the stimulatory effects of caffeine on sleep.
8: Alcohol is Bad News
Alcohol is known to inhibit CYP1A2 activity.
Consumption of alcohol significantly increases the caffeine half-life by 72%, and reduces its clearance by 36%.
Binge consumption of caffeine and alcohol (like combining energy drinks with alcohol) can lead to a hyperstimulated state, called the “wide-awake drunk state”.
My advice as a sleep specialist is simple – don’t mix alcohol and caffeine!
9: Be Mindful of Interactions Between Coffee and Medications
Since caffeine is metabolized by the CYP1A2 system, the use of medicines that affect the same enzyme system can lead to an alteration of the half-life of caffeine.
Hence, specific dosage adjustments are required in coffee drinkers.
While a complete list of medicines is out of the scope of this article, here are the common ones that can increase the effects of caffeine:
- Oral contraceptives.
- Quinolone antibiotics (e.g. ciprofloxacin, nalidixic acid, ofloxacin, norfloxacin, etc.).
- Cardiovascular drugs (e.g. mexiletine, diltiazem, verapamil, propranolol, warfarin, etc.).
- Central nervous system drugs (e.g. clozapine, venlafaxine, alprazolam, olanzapine, zolpidem, etc.).
- Anti-inflammatory drugs (rofecoxib, idrocilamide).
- Antifungal drugs (fluconazole, ketoconazole, and terbinafine).
- Anticonvulsants (phenobarbital, phenytoin, sodium valproate, and diphenylhydantoin).
- Antacids (cimetidine, lansoprazole, omeprazole, and pantoprazole).
Talk to your doctor or pharmacist to get a complete list.
In my personal experience, the effect is quite insignificant in most people.
However, if you already have a sleep problem, it may become relevant.
In such a case, it is useful to talk to your doctor.
10: Tolerance May Develop in Chronic Users
Long-term consumption of coffee can lead to the development of tolerance.
Tolerance refers to a state in which the dose required to reach the desired positive effects increases over time, leading people to gradually consume higher amounts of caffeine.
In the case of caffeine, you may develop a tolerance to the anxiety, jitteriness/nervousness, activity/stimulation/energy, but never fully develop a tolerance to the alertness and wakefulness.
Hence, consuming larger amounts of coffee can worsen sleep problems, such as increased sleep latency.
You can avoid tolerance by taking planned breaks from coffee.
11: Absorption of Caffeine Varies Depending on the Source
The absorption of caffeine is not constant from all sources.
It is known that caffeine in tea and coffee is absorbed faster than caffeine from cola and chocolate.
Hence, the effect of caffeine is quicker when consumed in coffee or tea format, and slower when consumed in other foods and beverages.
The absorption of caffeine from chewing gums and pain medicines is much faster than any of the above.
Avoid these products close to bedtime, unless it is a medication prescribed by your doctor.
How Does Coffee Keep You Awake?
Below is an explanation as to how coffee keeps you awake:
Caffeine Blocks the Adenosine Receptors
After absorption from the stomach, caffeine enters the bloodstream, and gets distributed all over the body.
A fraction of the caffeine enters the brain, and blocks the adenosine receptors.
Adenosine is a chemical produced in the brain, which normally promotes sleep.
The blocking of the adenosine receptors means the sleep-inducing effect of adenosine is curtailed, and the brain remains active and vigilant.
Recent research also shows that if consumed close to sleep time, caffeine can interfere with the melatonin hormone, which plays an important role in the circadian rhythm.
Caffeine Can Disrupt Sleep Quantity and Quality
Caffeine can cause latency of sleep, and reduce total sleep time, efficiency, and sleep satisfaction.
In addition to the latency, caffeine can also cause insomnia, or worsen pre-existing insomnia.
Older adults are particularly susceptible to caffeine-induced sleep problems.
A research study that examined the effects of caffeine intake at zero, three, and six hours before routine bedtime, found that even a single cup of coffee consumed six hours before bedtime could reduce sleep time by one hour.
Caffeine can also affect sleep architecture, and decrease the time spent in deep sleep (slow-wave sleep).
This can lead to excessive daytime sleepiness, fatigue, and cognitive changes.
Caffeine is also linked to an increase in the severity of sleep-disordered breathing, and obstructive sleep apnea.
Interestingly, this effect is seen only with caffeinated sodas, and not as a result of coffee.
If you feel that you lack energy during the daytime, have excessive daytime sleepiness, or wake up unrefreshed in the morning, you should evaluate if caffeine is perhaps the villain.
How to Sleep After Drinking Coffee Too Late
If you are susceptible to sleep problems after drinking coffee, try the following steps to get a good night’s sleep.
Turn Off Your Smartphone and Television
Just as caffeine stimulates your brain, smartphones and television can prevent your brain from relaxing.
The additive effects of coffee and electronics can be particularly detrimental to sleep.
The blue light from the screen can decrease the production of the melatonin hormone, which can affect the sleep-wake cycle, and cause sleeplessness.
Hence, you should switch off your smartphone and television before bedtime.
Do Exercise, Meditation, or Yoga
Doing light exercises, meditation, and yoga can calm your mind, relax your body, and facilitate sleep if you have had coffee.
A simple yet effective meditation is to sit or lay down in a comfortable position, and take deep breaths while focusing on your breath and body movements.
After a few minutes, you will feel relaxed, and fall asleep.
Light exercise can also be of help.
If you have a back yard, a brisk walk can help you get to sleep quickly.
Walking can help you unwind your mind and body before bedtime, and can burn some of the extra caffeine out of your system.
Yoga is another great way to relax.
I have listed a few meditative poses to help you wind down at night after coffee consumption.
- Child’s Pose is a great way to relax your back, neck, shoulder muscles, thighs, and ankles.
- Standing Forward Bend is performed by standing with your feet 6 inches apart, and folding the upper part of the body to the ground while bending the arms, and clutching the hand to the opposite elbow.
- Corpse Pose will get your body into sleep mode quite quickly. It also releases serotonin, which is linked to happiness and relaxation.
Take a Warm Bath
A warm bath or shower can help your muscles relax, and help you get to sleep faster.
Take a warm bath at 104 to 107°F (40 to 42°C), about 60 to 90 minutes before bedtime.
Use Essential Oils
Essential oils can help you sleep better.
These include lavender oil, chamomile, frankincense, and mandarin essential oils.
They are most effective when used with a diffuser in your room.
Read a Book
Reading can dull down a charged mind, reduce stress, and help put you to sleep.
A recent study has reported that reading a book for 6 minutes each night can reduce stress up to 68%, and help you sleep.
You should give reading a try if you feel too charged after coffee.
Don’t Eat Too Close to Bedtime
Eating close to bedtime can prevent you from sleeping.
Nutritionists recommend at least a three-hour wait after your last meal, before going to bed.
This allows some digestion to happen, and the contents of your stomach to move into your small intestine.
This point is especially pertinent if you have gastritis and acid reflux.
Drinking enough water can help flush caffeine out of your body.
Drinking 1 to 2 liters of water can kill the buzz caused by caffeine.
Melatonin is a natural hormone that regulates wakefulness and sleep.
Melatonin supplements can improve sleep architecture.
These are available from the pharmacy, without a doctor’s prescription in most countries.
Drink Chamomile Tea
Chamomile can cause mild sedation by acting through the benzodiazepine receptors, much like a sleeping pill does.
To help you sleep, drink chamomile tea without caffeine, a half to one hour before your normal sleeping time.
Take a Vitamin C Tablet, or Eat Citrus Fruits
The high doses of vitamin C in citrus fruits can hasten the process of clearance of caffeine from your system.
Alternatively, you can take a vitamin C tablet, which you can get in all pharmacies.
Coffee is a double-edged sword.
On one hand, it relieves physical and mental fatigue, and on the other, it keeps your brain stimulated, and keeps sleep at bay.
To get a restful night’s sleep, you should be mindful of the type of coffee you are consuming, its caffeine content, and the time at which you have your last cup.
You should be especially careful if you already have pre-existing sleep problems.
You can follow the above recommendations for a good night’s sleep.
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2: O’Callaghan F, Muurlink O, Reid N. “Effects of caffeine on sleep quality and daytime functioning”. Risk Manag Healthc Policy. 2018 Dec 7;11:263-271.
3: Nehlig A. “Interindividual Differences in Caffeine Metabolism and Factors Driving Caffeine Consumption”. Pharmacol Rev. 2018 Apr;70(2):384-411.
4: Mysliwiec V, Brock MS. “Does coffee consumption impact sleep-disordered breathing?”. Sleep Breath. 2019 Dec;23(4):1033-1034.
5: Alharbi WDM, Azmat A, Ahmed M. “Comparative effect of coffee robusta and coffee arabica (Qahwa) on memory and attention.” Metab Brain Dis. 2018 Aug;33(4):1203-1210.
6: https://www.uptodate.com/contents/benefits-and-risks-of-caffeine-and-caffeinated-beverages. Retrieved on 01-03-2022
No part of this website offers medical advice – consult with a qualified professional for the best guidance.
Image Attribution and Licensing
Main image: ‘Coffee Cup, Coffee Beans’ by amenic181(used with permission and commercially licensed through Envato Elements).
Dan is the founder and head content creator at Bedroom Style Reviews.
He has been working as a professional online product reviewer since 2015 and was inspired to start this website when he ended up sleeping on a memory foam mattress that was too soft and gave him backache.
Through in-depth research and analysis, Dan’s goal with this website is to help others avoid such pitfalls by creating the best online resource for helping you find your ideal mattress, bedding, and bedroom furniture.
Dan is a qualified NVQ Level 2 Fitness Instructor with 6 years’ experience helping clients improve their health through diet, exercise, and proper sleep hygiene.
He also holds several college and university-level qualifications in health sciences, psychology, mathematics, art, and digital media creation – which helps him to publish well researched and informative product reviews as well as articles on sleep, health, wellbeing, and home decor.
Dan also has direct personal experience with insomnia, anxiety, misophonia (hypersensitivity to sounds), and pain from both acute and long-standing sporting injuries – he enjoys writing insightful articles around these subjects to help fellow sufferers of such conditions.
Learn more about Dan here.