Why Coffee Makes Some People Feel Tired

It sounds like a contradiction. Coffee is the drink people reach for when they want to wake up, yet a large number of people say the opposite happens to them. They drink a cup, feel awake for a short while, and then feel more tired than before. Some feel sleepy almost straight away. Others feel fine in the morning and then hit a heavy slump in the afternoon, even though they have had two or three cups. A few say coffee has stopped working for them altogether, and they drink it out of habit rather than because it helps. If that sounds familiar, you are not imagining it, and you are not doing coffee wrong. Coffee really can make some people feel tired, and the reasons are well understood once you look at how caffeine works in the body, how sleep works, and how different bodies handle the same drink in different ways.

The short version is this: coffee does not give you energy. It borrows alertness from later in the day. It blocks the brain’s sleep signal for a while, and when that block wears off, the sleep signal comes back, often stronger than before. If you are already short of sleep, if you drink coffee late in the day, if you drink a lot of it, or if your body clears caffeine slowly, that borrowed alertness can turn into a crash. Add in low blood sugar, dehydration, a heavy meal, or a sugary coffee, and the tired feeling can be even stronger. This article explains each of those causes in plain words, so you can work out which one fits you, and what small changes might help. It is general information only, not personal medical advice. If tiredness is strong, constant, or comes with other symptoms, a health professional is the right person to ask.

How Caffeine Wakes You Up, and Why That Wake-Up Fades

To understand why coffee can make you tired, you need to understand how caffeine works. While you are awake, your brain slowly builds up a chemical called adenosine. The longer you stay awake, the more adenosine builds up, and the sleepier you feel. Sleep clears adenosine away, which is why you wake up feeling fresh after a good night. Caffeine works by sitting in the same places in the brain where adenosine normally sits, and blocking it. The adenosine is still there, but the brain cannot feel it while caffeine is in the way. That is why you feel awake after coffee. The tiredness has not gone away. It has been hidden for a while.

The hiding does not last forever. Caffeine is slowly cleared from the body, usually over several hours. As it clears, the blocked adenosine can be felt again, all at once. The brain suddenly notices all the adenosine that built up while caffeine was hiding it, and the person feels a wave of tiredness. This is often called a caffeine crash. It is not a sign that coffee has harmed you. It is the normal result of borrowing alertness. The crash feels worse when the person was already very tired before the coffee, because there was a lot of adenosine waiting behind the block. It also feels worse when the person drinks a large amount of caffeine at once, because the block is stronger and the return is sharper.

Timing changes this a lot. If you drink coffee first thing in the morning, the caffeine blocks the small amount of adenosine left over from the night, and you feel awake. If you drink coffee in the late afternoon, when adenosine has been building up all day, the block is hiding a much larger amount, and the crash when it wears off can feel heavy. That is why many people feel fine after a morning cup and terrible after a late afternoon cup. The coffee is the same. The amount of sleepiness waiting behind it is different. The same logic applies to the amount you drink. One cup hides a moderate amount of tiredness. Three cups in quick succession hide a lot, and the return can feel like hitting a wall.

The Crash When Caffeine Wears Off

The crash is the most common reason people say coffee makes them tired, and it has a clear pattern. The person drinks coffee, feels sharper for one to two hours, and then feels more tired than before the coffee. The eyes feel heavy, the head feels foggy, and the body feels slow. Some people feel a headache as well, or a low mood that lifts only when they drink another cup. That next cup hides the tiredness again, for another hour or two, and then the crash comes back, often a little stronger. By the end of the day, the person has drunk several cups, slept badly that night because of the late caffeine, and woken up tired again the next morning. It becomes a loop, and the loop is hard to see from inside it, because each cup feels like the fix for the tiredness that the last cup helped to cause.

Sleep is the key to breaking that loop, but it is also the part people find hardest to change. Caffeine stays in the body for a long time. Even a cup drunk at four in the afternoon can still be partly present at bedtime, and it can make sleep lighter and shorter, even if the person falls asleep easily. Lighter sleep clears less adenosine, so the person wakes up with more sleepiness left over, and needs more coffee to hide it. That is why the advice to stop drinking coffee early in the day is so common. It is not about giving up coffee. It is about giving the caffeine time to clear before sleep, so that sleep can do its proper job of clearing tiredness, and the next morning’s coffee has less to hide.

The crash also depends on how much caffeine you are used to. A person who rarely drinks coffee feels a strong lift from one cup, because their brain is very sensitive to it. A person who drinks five cups a day feels much less from each cup, because the brain has adjusted. The body makes more adenosine receptors over time when caffeine is always present, which means it needs more caffeine to get the same block. That is tolerance, and it is why heavy coffee drinkers often say coffee no longer wakes them up. They are not imagining it. Their brain has adapted, and the same amount that once felt strong now feels normal. When they drink even more to chase the old feeling, the crash when it wears off is bigger, and the loop gets tighter.

Sleep Debt: When Coffee Is Hiding Real Tiredness

The most important cause of tiredness after coffee is also the simplest: the person is genuinely tired, and coffee is only hiding it. Sleep debt is the name for the tiredness that builds up when you sleep less than your body needs, night after night. It does not go away with a cup of coffee. It does not go away with a weekend lie-in, though that helps a little. It only goes away with regular, sufficient sleep over days and weeks. Coffee can hide sleep debt for an hour or two, but it cannot pay it off. When the caffeine wears off, the debt is still there, waiting, and it often feels larger because the person has been pushing through it all day.

Many people live with a small sleep debt without realising it. They sleep six hours a night, feel tired in the afternoon, drink coffee to get through it, and think that is normal. It is common, but it is not the same as being rested. A rested person wakes up without an alarm feeling fairly clear, stays steady through the day, and feels sleepy at a sensible time in the evening. A person with sleep debt wakes up groggy, needs coffee to feel human, crashes in the afternoon, needs more coffee, and then struggles to sleep that night. Coffee is not the cause of the debt, but it can hide the debt during the day and make it worse at night, because late caffeine disturbs sleep. That is the loop again, and it is the reason many people find that cutting back on coffee, especially late in the day, actually makes them feel less tired after a few days, even though the first day or two without as much caffeine feels harder.

Age and life stage change sleep debt too. Parents of young children, shift workers, students in exam season, and people who work long hours often carry a large sleep debt for months. For them, coffee feels less effective because there is simply too much tiredness to hide. No amount of caffeine can cover a body that has not slept properly for weeks. The tiredness after coffee in those cases is not a coffee problem. It is a sleep problem, and the coffee is just the messenger. The honest fix is more sleep, which is easy to say and hard to do, but it is the only fix that actually clears the adenosine that coffee has been hiding.

Sugar, Food and Dehydration After Coffee

Coffee itself has almost no calories and no sugar, but the way many people drink it changes that completely. A large coffee with sugar, syrup, and sweetened milk can contain as much sugar as a soft drink. That sugar raises blood sugar quickly, gives a short lift, and then lets blood sugar fall again, often to a level lower than before. That fall feels like tiredness, fogginess, and hunger, and it often arrives one to two hours after the coffee, at exactly the same time as the caffeine is starting to wear off. The two effects combine, and the person feels a heavy slump. They often blame the coffee, when the sugar in the coffee is doing a large part of the work. Plain coffee, or coffee with only a little milk and no sugar, is much less likely to cause that sugar swing.

Food matters in the other direction as well. Coffee on an empty stomach can make a person feel shaky and then tired, because the caffeine is absorbed quickly, the stomach is empty, and blood sugar is low after the night. A person who drinks coffee instead of breakfast often feels awake for an hour and then very tired and hungry by mid-morning. That is not just the caffeine wearing off. It is the body running out of fuel. Coffee gives no fuel. Food gives fuel. When the fuel is missing, the body slows down, and no amount of caffeine can replace a meal. Eating something with, or before, coffee steadies the whole morning, because the body has real energy to work with, and the caffeine is released more slowly.

Dehydration plays a smaller but real part. Many people wake up mildly dehydrated after a night without water, and they drink coffee instead of water. Caffeine can make you pass urine a little more often, so the body can end up drier than before. Even mild dehydration can make a person feel tired, headachy, and foggy, and it can make the caffeine crash feel worse. A glass of water before coffee, and water through the day, does not fix sleep debt or tolerance, but it removes one more reason to feel tired. It is a small habit, and it is easy to overlook, but for people who drink several cups of coffee and very little water, it can make a noticeable difference.

Tolerance, Timing and How Much You Drink

Tolerance is the body’s way of getting used to a regular drug, and caffeine is a drug in the mild sense of the word. When you drink caffeine every day, your brain adjusts by making more of the places where adenosine sits, so that the same amount of caffeine blocks a smaller share of them. The result is that the same cup feels weaker over weeks and months. Many people respond by drinking more, which works for a while, and then the brain adjusts again. The person ends up drinking four or five cups a day just to feel normal, and they feel tired whenever the caffeine level drops, even slightly. That tiredness is not the coffee making them tired in the moment. It is the brain noticing the gap between the high caffeine level it has come to expect and the lower level that is actually there.

Timing through the day makes tolerance worse or better. Drinking coffee at the same time every morning is a steady habit, and the body adjusts to it. Drinking coffee at random times, in large amounts, late in the day, and on top of poor sleep makes the ups and downs much sharper. The most useful change for many people is to keep coffee to the morning, to keep the amount steady rather than increasing it, and to leave a gap of several hours between the last cup and bedtime. That gap lets caffeine clear, lets sleep be deeper, and lets the next morning start with less debt. Some people find that a short break from caffeine, of a few days, resets their sensitivity, and one cup feels strong again. That break can be uncomfortable for a day or two, with headaches and tiredness, which is why it is best done on days when the person can rest, and why it is worth talking to a health professional first if the person has health conditions or takes regular medicine.

The amount also matters in a way people often miss. A small cup of coffee and a very large mug are not the same, and a coffee shop’s large size can contain two or three times the caffeine of a small home cup. Energy drinks, which some people drink alongside coffee, add even more caffeine, and the total can be far higher than the person realises. When the total is very high, the body feels wired and then crashes hard, and the person feels exhausted rather than awake. Keeping track of the total, not just the number of cups, helps. If you drink coffee at home, at work, and from a shop, the total can add up quickly, and the tiredness at the end of the day may be the bill coming due for a large amount of borrowed alertness.

Why Bodies Handle Coffee Differently

One of the most interesting things about coffee is how differently it affects different people. Some people drink a cup at nine in the evening and fall asleep easily. Others drink a cup at noon and lie awake that night. Some feel energised by one cup. Others feel jittery and then tired from the same cup. These differences are not in the imagination. They come from real differences in how the body clears caffeine, how sensitive the brain is to it, and how the body handles stress. The liver clears caffeine using enzymes, and the speed of those enzymes varies from person to person, partly because of genes. A fast clearer can drink coffee late and sleep well. A slow clearer can still have caffeine in their body many hours after a morning cup, and feel its effects, including disturbed sleep, long after the cup is finished.

Body size, age, and smoking also change how caffeine works. A smaller person feels a given amount of caffeine more strongly than a larger person, because the same amount is spread through less body. Older people often clear caffeine more slowly, which is why a cup that felt fine at thirty can feel too strong at sixty. Smoking speeds up caffeine clearance, which is why people who smoke often drink more coffee, and why stopping smoking can suddenly make the same amount of coffee feel much stronger. Hormones play a part too. During pregnancy, caffeine is cleared much more slowly, which is one reason pregnant people are often advised to keep caffeine low. None of these factors is a fault. They are just differences, and they explain why advice about coffee that works for one person can be useless for another.

Sensitivity to caffeine is also a real difference. Some brains react strongly to a small amount of caffeine, with a racing heart, shaking hands, and a feeling of anxiety, followed by a heavy tiredness when it wears off. Other brains react mildly, and the person feels only a gentle lift. The sensitive person is more likely to say coffee makes them tired, because the jolt is followed by a crash that feels bigger than the lift. The less sensitive person is more likely to say coffee works well, because the lift is smooth and the crash is small. Knowing which type you are helps you choose the right amount. A sensitive person often does better with a small cup, or with half-caffeine coffee, or with tea, which has less caffeine and releases it more slowly. A less sensitive person can often drink a normal amount without trouble, as long as they do not drink it late.

When Tiredness After Coffee Is a Signal to Notice

Most tiredness after coffee has a simple explanation: sleep debt, a caffeine crash, tolerance, sugar, or timing. But tiredness is also a signal the body uses for many other things, and it is worth noticing when the pattern changes. If you have always drunk coffee without trouble and suddenly feel very tired after it, or if the tiredness comes with other changes, such as a low mood that does not lift, a loss of appetite, a change in weight, or a need to sleep far more than usual, those changes are worth taking seriously. General information in an article cannot tell you what is causing them, and it should never be used to explain away a change that is new, strong, or persistent.

Iron levels, thyroid problems, low mood, and poor sleep from snoring or other causes can all make a person feel tired through the day, and coffee will not fix any of them. In those cases, the tiredness after coffee is not caused by the coffee. The coffee is just failing to hide a tiredness that has another cause, and the failure makes the tiredness more noticeable. That is useful information, not a reason to drink more coffee. If tiredness is constant, if it affects work, driving, or daily life, or if it comes with other symptoms, a health professional can check the things that an article cannot, and that check is the right next step. It is better to ask early than to spend months drinking more coffee to cover a tiredness that needs a different kind of help.

It is also worth noticing the emotional side of tiredness after coffee. Many people drink coffee when they are stressed, bored, or low, and they expect it to fix the feeling. Coffee can give a short lift in mood and focus, but it cannot fix stress, boredom, or low mood, and when the lift fades, the original feeling comes back, sometimes feeling worse by comparison. That is not a failure of coffee. It is a sign that the feeling had a different cause, and that cause is still there. A short walk, a glass of water, a proper meal, or a few minutes of rest can sometimes do more for that kind of tiredness than another cup, because they address the body rather than hiding the signal. Learning to tell the difference between sleepy tiredness, hungry tiredness, and stressed tiredness is a useful skill, and it helps a person choose the right response instead of reaching for coffee every time.

My Take:

If you ask me why coffee makes some people feel tired, my answer is simple: because coffee does not give you energy, it hides tiredness, and hiding something is not the same as removing it. I think that one sentence explains most of the confusion about coffee. People expect a drink to fill them up with energy, the way food fills them up, and when it does not, they think something is wrong with them, or with the coffee. Nothing is wrong. Coffee was never meant to be fuel. It was meant to be a short, sharp lift, a way to feel awake for a while when you need to be awake. When the lift ends, the tiredness you were hiding comes back, and it often feels larger because you have spent the last few hours ignoring it. That is not coffee betraying you. That is coffee doing exactly what it does, and your body telling you the truth once the cover is gone.

I think the most common version of this story is the afternoon slump, and I have seen it many times. A person drinks coffee in the morning, feels good, works well, and then drinks another cup in the early afternoon to keep going. For an hour, it works. Then the tiredness comes back heavier than before, the eyes feel heavy, the head feels foggy, and the person reaches for another cup. By evening, they have had four or five cups, they feel wired and tired at the same time, and they sleep badly that night. The next morning, they wake up groggy and start the whole cycle again. When that person says coffee makes them tired, they are right, but the coffee is not the beginning of the story. The beginning is the poor sleep the night before, and the middle is the late coffee that made the sleep worse. The tiredness after coffee is the end of a loop that started the night before, and the only way to break a loop is to change one part of it, not to drink more of the thing that keeps it going.

I also think we need to be honest about tolerance, because it is the part people least want to hear. When you drink coffee every day, your brain gets used to it. The lift gets smaller, the crash gets bigger, and you need more coffee to feel normal. That is not a personal failure. It is how the brain works with any regular stimulant. But it does mean that the person who drinks five cups a day and says coffee no longer works is telling the truth, and the answer is not a sixth cup. The answer is to step back, to drink less for a while, to let the brain reset, and to let sleep do the work that coffee has been trying to do. I know that sounds hard, especially for a person who relies on coffee to get through work, and the first day or two of drinking less can feel worse, with headaches and heavy tiredness. That is the brain noticing the gap. It passes, and after a few days, one cup can feel strong again. In my view, that reset is worth more than any extra cup, because it gives the person their sensitivity back.

There is another point I feel strongly about, and it is about sugar. Many people do not drink plain coffee. They drink large, sweet coffees with sugar, syrup, and sweet milk, and they wonder why they crash an hour later. The sugar is doing a lot of that work. It lifts blood sugar quickly, then lets it fall, and the fall feels like tiredness, hunger, and fogginess. Add the caffeine wearing off at the same time, and the slump feels twice as heavy. I am not saying people must drink black coffee if they hate it. I am saying they should know what is in their cup, and they should notice the pattern. If a plain cup leaves you steady and a sweet cup leaves you crashing, the difference is not the coffee. It is the sugar. A smaller sweet coffee, or a coffee with less sugar, or a plain coffee with a proper breakfast, can change the afternoon completely, and it costs nothing to try.

I also want to say something about the people who feel sleepy almost straight after coffee, because their experience is often dismissed. Some people really do feel drowsy after caffeine, and there are good reasons for it. If the body clears caffeine slowly, the lift and the crash can overlap. If the person is very tired, the amount of sleepiness waiting behind the caffeine block is so large that even a strong block cannot hide it for long. If the person is sensitive to caffeine, the jolt can be followed by a heavy drop. And if the person has drunk coffee on an empty stomach, with no food and little water, the body is running on empty, and coffee cannot fill an empty tank. None of these people is doing coffee wrong. They are just learning, often the hard way, that their body handles caffeine differently from their friend’s body, and that they need a smaller amount, a different time, or a different drink altogether. Comparing yourself with a friend who can drink coffee at midnight and sleep like a baby is a poor way to judge your own body. Your body is the only one that matters here.

In my view, the best use of coffee is a modest one. One or two cups in the morning, after food and water, with no sugar or only a little, and nothing after the early afternoon, is a pattern that suits most people. It gives a lift when the day is starting, it leaves plenty of time for the caffeine to clear before sleep, and it does not build up a large tolerance. The worst use of coffee is the opposite: cup after cup through the day, late into the afternoon, with sugar, on an empty stomach, to cover a sleep debt that keeps growing. That pattern does not make a person more awake. It makes them more tired, more wired, and more dependent on the next cup. I think many people would feel less tired if they drank less coffee, not more, and that is a strange idea to say about a drink that is sold as an energy drink, but it is true for a large number of people.

I think we also need to be honest about the limits of what coffee can do, and about what tiredness really means. Tiredness is not always a coffee problem. Sometimes it is a sleep problem, sometimes it is a food problem, sometimes it is a low mood, and sometimes it is a health problem that needs checking. Coffee can hide all of those things for an hour, but it cannot fix any of them, and when the hiding ends, the real cause is still there. If you are tired every day, if the tiredness does not lift after a good night’s sleep, if it comes with other changes, or if it affects your work, your driving, or your daily life, please ask a health professional. That is not a formal line to add at the end. It is the most important advice in this article. A cup of coffee is a small thing. Your health is a large thing, and it deserves a proper check when it sends you a signal that does not go away.

So here is my final view, in plain words. Coffee can make some people feel tired because it hides tiredness instead of removing it, because the crash when it wears off can feel heavier than the lift, because tolerance makes each cup weaker over time, because sugar and an empty stomach add their own slump, and because bodies clear caffeine at different speeds. If coffee makes you tired, try the simple changes first: keep it to the morning, keep the amount steady and moderate, eat before or with it, drink water, skip the sugar, and protect your sleep by stopping early in the day. Give it a week and see how you feel. If the tiredness lifts, you have your answer, and you can keep your coffee in a smaller, kinder place in your day. If the tiredness stays, or if it is strong and constant, ask a health professional, because your body may be telling you something that coffee was never meant to fix. Either way, you will have learned something useful about yourself, and that is worth far more than another cup.

If a friend asked me whether they should keep drinking coffee when it makes them tired, I would ask them when they drink it, how much they drink, and how they sleep. If they drink five cups a day, late into the afternoon, and sleep badly, I would say the coffee is part of the loop, and cutting back, especially late in the day, is the first thing to try. If they drink one cup in the morning and still feel tired, I would say the tiredness is probably not about the coffee at all, and sleep, food, and a health check are the things to look at. I would not tell them to quit coffee on the spot, because quitting suddenly can feel rough, and because a friend who loves coffee will not quit on my say-so anyway. I would tell them to make coffee smaller, earlier, and plainer, and to give sleep a proper chance for a week. That advice is not dramatic, and it is not new, but it works for most people, and it lets them keep something they enjoy without paying for it with a heavier slump every afternoon.

One last thought: the afternoon slump is not a personal failure, and it is not a sign that you are lazy. It is a sign that your body has been awake for many hours, that it has used up a lot of its resources, and that it needs rest, food, or water, not another stimulant. A short walk, a glass of water, a proper lunch, or a few minutes of rest can sometimes do more for that kind of tiredness than another cup, because they give the body what it actually needs. Coffee is a useful tool, and like any tool, it works best when it is used in the right place, at the right time, in the right amount. Used well, it can help you start the day clearly. Used all day, every day, to cover a tiredness that keeps growing, it can leave you more tired than when you started. In my view, learning that difference is one of the most useful things a coffee drinker can learn, and it is a lesson worth keeping.

I also think it helps to test your own pattern instead of guessing, because a one-week test gives you a clear answer that no article can. Try a simple experiment: for three days, drink coffee exactly as you do now, and write down when you drink it, how much you drink, and how tired you feel at three in the afternoon. Then for the next three days, keep coffee to the morning only, drink one cup less, eat something with it, and drink a glass of water first, and write down the same afternoon feeling. Do not change your bedtime or your other meals in those six days if you can help it. At the end of the week, look at the two sets of notes side by side. Most people find the difference is plain to see, and once you have seen it in your own notes, you do not need anyone else to tell you what to do. Your body has already told you, and that kind of evidence is far more convincing than any general advice.

Another idea worth trying is to change the drink itself for a few days, not just the timing. If you normally drink large, sweet coffees, try a plain cup for a week and see whether the afternoon slump softens. If you normally drink coffee all day, try tea in the afternoon instead, because tea has less caffeine and releases it more slowly, and many people find the afternoon feels steadier with tea than with a third or fourth coffee. If you drink energy drinks as well as coffee, try counting the total caffeine from both together, because the combined amount is often much higher than people realise, and the crash at the end of the day may be the bill for that total. You do not have to keep any of these changes forever. You are simply learning which version of your day leaves you feeling steadier, and once you know that, you can keep the version that suits you.

Finally, I want to be clear about what I am not saying. I am not saying coffee is bad, and I am not saying everyone who feels tired after coffee should stop drinking it. Some people drink one cup in the morning, feel clear all day, and sleep well at night, and they should keep their habit exactly as it is. Some people have busy lives, young children, or shift work, and they cannot get more sleep no matter how much they want to, and coffee is the tool that helps them get through the day. That is understandable, and it is not a failure. The point of this article is not to give you a new rule. It is to help you see the loop between tiredness, coffee, and sleep, and to give you a few small changes to try if that loop applies to you. Health advice works best when it fits a real life, and a small change that fits is worth far more than a large change that does not last.

Frequently Asked Questions

What does “Why Coffee Makes Some People Feel Tired” really mean?

It means asking why a drink meant to wake you up can leave some people feeling sleepy or sluggish instead. The main reason is that caffeine blocks the brain’s sleep signal, adenosine, without removing it. When caffeine wears off, that sleepiness returns, often feeling stronger, which is why the tiredness can feel worse after coffee than before it.

Why do so many people search for “Why Coffee Makes Some People Feel Tired”?

Many people drink coffee to feel awake, then feel a heavy slump an hour or two later, or find that coffee has stopped working for them. They want to know whether that is normal, whether they are drinking too much, and whether sleep, sugar, or timing is playing a part in how they feel.

How long does the feeling behind “Why Coffee Makes Some People Feel Tired” usually last?

The tired feeling after a caffeine crash often lasts from half an hour to a few hours, and it usually lifts after rest, food, or a proper night’s sleep. How long it lasts depends on how tired the person was before the coffee, how much caffeine they drank, and when they drank it. If tiredness is constant through the day, every day, it is more than a single crash.

What makes “Why Coffee Makes Some People Feel Tired” feel stronger on some days?

Poor sleep, a large amount of caffeine, drinking coffee late in the day, a sugary coffee, an empty stomach, dehydration, and stress can all make it feel stronger. That is why the same cup can feel fine on a rested day and leave a heavy slump on a tired day, when there is simply more sleepiness waiting behind the caffeine.

Can daily habits change anything about “Why Coffee Makes Some People Feel Tired”?

Yes, daily habits often change it a lot. Keeping coffee to the morning, keeping the amount steady and moderate, eating before or with coffee, drinking water, cutting back on sugar in coffee, and protecting sleep by stopping coffee early in the day all help many people feel less tired after coffee.

When should I pay closer attention to “Why Coffee Makes Some People Feel Tired”?

Pay closer attention if tiredness is strong, constant, or new, if it affects work, driving, or daily life, or if it comes with other changes such as low mood, loss of appetite, weight change, or a need to sleep far more than usual. In those cases, ask a health professional, because tiredness can have causes that coffee cannot fix. This is general information only, not personal advice.