Why Does Coffee Make Me Sleepy Instead of Awake?

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We drink coffee to stay awake. I mean, all that caffeine will definitely keep you buzzing for a while, right? So, why does coffee sometimes make you feel sleepy?

4 Reasons Why You Feel Sleepy

You’re Dehydrated

Coffee is a diuretic. This means that it makes you want to wee. This causes dehydration, which, in turn, makes you tired. Yikes! So, if you’re drinking coffee to stay awake, ensure that you drink enough water to maintain proper fluid levels in your body.

You Get an Adenosine Rush

Adenosine is the hormone your body produces to make you sleepy. When you drink coffee, the caffeine blocks the adenosine receptors in your brain, so you don’t feel tired right away. Your body is still producing adenosine, though, and it’s waiting around for receptors to become available. So, when the effect of the caffeine wears off, all that adenosine rushes to the receptors, eager to be heard. This means that you feel the overwhelming effect of all that built-up adenosine all at once. Sucks, right?

Your Coffee is too Sweet

If you drink your coffee very sweet, you get a sugar rush with your cuppa Joe. Sugar is digested much faster than caffeine, so you feel that rush immediately. On the downside, you’ll crash when that rush ends. When sugar is metabolized, it leaves you feeling very fatigued and without energy. So, if you’re using coffee to keep you awake, maybe take it easy on the sugar.

Not Enough Coffee

You have your cup of coffee, and it’s great. Then, after a bit, you feel super tired and wonder why this wonderful beverage makes you so sleepy when you’re counting on it to keep you going. That could be because the effect of the caffeine wore off. If you have a super-fast metabolism, you’ll digest that caffeine in no time. This means that you’ll need another cup to top up your caffeine levels or endure the slump that follows when the caffeine wears off.

How Long Does it Take for the Coffee to Start Having an Effect?

If you’ve ever taken coffee to help you through an all-nighter, you’ve probably had that moment where you ask yourself, “when will this kick in?” You can feel the effect of coffee in as little as ten minutes after you drink it. The caffeine spike will occur about 45 minutes later, though. So, timing is everything.

How to Minimise the Sleep Effects?

Now you know that coffee can make you sleepy. So, if you want to stay awake, how do you minimize the sleep effects?


If coffee makes you sleepy, don’t overdo it. Drinking more coffee lets you experience more side effects. Makes sense, right?

Avoid Sugar

Since sugar causes you to crash shortly after you drink it, avoid drinking overly sweet coffee. Also, avoid heavily sweetened caffeinated drinks. You know, like those fake cappuccino sachets. The ones that give you “instant cappuccino.” Yuck.

Drink Water

Fight the caffeine-induced dehydration by drinking lots of water. If you’re having trouble remembering, ensure that you fill a glass of water when you make a cup of coffee. Then, don’t make another cup of coffee before you’ve emptied that glass of water.

Other Positive Effects of Coffee 

The effects of coffee on our bodies are well-researched. While we know that there are adverse effects, there are also plenty of health benefits associated with our favorite beverage. Here are a few:

Increased Fibre

The recommended daily fiber intake for adults is 20-38 grams. A standard cuppa Jo contains about 1.8 grams of fiber. So, when you’re having your morning coffee, you’re kickstarting your fiber dose for the day. Go you!

Reduce Muscle Aches Post-Workout

When you’ve hit the gym hard, you’ll probably feel it for the next few days. Research has shown that having two cups of coffee after a workout reduces the muscle ache associated with exercise by up to 48%. That’s a great reason to relax at the gym coffee shop after you bent some iron.

Decreased Risk of Diabetes

Research shows that people who drink six cups of coffee per day are 22% less likely to develop type II diabetes. If you’re not keen on caffeine, you could even opt for the decaf version – although the benefit in terms of diabetes prevention is lower, there is still a link. Now, just avoid all that extra sugar, right?

Prevent Alzheimer’s Disease

There is lots of evidence to prove that coffee consumption lowers your risk of developing Alzheimer’s disease. Some scientists have even isolated the compounds in coffee that clean up the brain plaque that potentially causes Alzheimer’s. How cool is that? Now you can power through the night and rest assured that you’re giving your brain the best shot at longevity.

Reduce the Risk of Suicide and Depression

This is a big one. A group of scientists undertook a 10-year study of nurses to determine the effect of their coffee habits. They found that those who love their morning (midnight? All night?) brew were 20% less likely to suffer from depression or risk suicide. Maybe the time-out that comes with that cuppa Joe has something to do with it?

Protect Your Liver

The obvious way to protect your liver from cirrhosis (chronic damage and scarring) is to have less alcohol. The other option is to have coffee. Yup, having regular or decaffeinated coffee decreases the liver enzyme levels. This, in turn, reduces the risk of scarring and other damage that leads to liver failure in the long run. So, when those coffee haters tell you that you’re poisoning yourself, tell them that you’re only looking out for your liver.

Protect against Parkinson’s

Research has shown that if you smoke, drink, and have coffee, you’re less likely to develop Parkinson’s than your health fanatic sibling. A group of leading scientists also found that even when you’re genetically predisposed to Parkinson’s, drinking coffee reduces your risk of developing the disease. Here, the caffeine and EHT found in coffee beans work together to improve your odds. So, that’s your license to have some fun. Just beware of lung cancer and liver failure on the way.

Lower Risk of Multiple Sclerosis

If you drink more than three cups of coffee a day, you’re less likely to develop multiple sclerosis (MS). Multiple sclerosis is an immune-mediated disorder where your immune system attacks your body. Scientists suspect that the coffee prevents neural inflammation, a possible cause of multiple sclerosis.

Decrease the Risk of Colorectal Cancer

Research has shown that drinking coffee decreases the risk of developing colorectal cancer. Moderate coffee consumption reduces this risk by as much as 26%. So, drink more coffee for better odds.

Other Negative Effects of Coffee 

While coffee has plenty of health benefits, there are some downsides too. Few things in life are only good, right? Here are a few of them:

High Blood Pressure

If you’re not used to having coffee, you’ve probably felt like your heart might jump out of your chest after having a cup of coffee. Sound familiar? Studies have shown that coffee causes an increase in blood pressure, especially in those already prone to hypertension (high blood pressure) and those that don’t generally drink coffee. In two different studies, people were given various doses of caffeine, after which their blood pressure was monitored. Commonly, an increase in blood pressure was seen for 2-3 hours after they ingested the caffeine. So, if you’re prone to hypertension, maybe moderate your coffee intake or stay away altogether. Or, perhaps opt for a quality decaf version?

Heart Attacks in Young Adults

Studies showed that young adults who are prone to hypertension (high blood pressure) are four times as likely as their peers to suffer heart attacks. This is if they consume about four cups of coffee daily. That’s huge! The risk decreased as they drank less coffee. Still, that’s pretty scary.

Gout Attacks

Gout is a pretty nasty thing to suffer from. Imagine avoiding acidic foods, like tomatoes, curries, and citrus. Then, you pull an all-nighter and hit the coffee stand to pull you through. The next day, you can barely walk because of gout chewing at your big toe. Man, that sucks! Studies showed that bingeing on caffeine increases your risk of gout attacks, especially if you’re prone to gout flare-ups. If that’s you, maybe go easy on the brew.

Breast Tissue Cysts in Women

Turns out that having four cups of coffee per day increases your risk of developing fibrocystic breast disease by 150%. That’s massive! Doubling your coffee intake increases that risk to 230%. 

Risk Incontinence

If you drink lots of coffee (we mean a lot), you’re 70% more likely to suffer from incontinence in the long term. Shucks. Maybe you should slow down a bit?


This one seems kind of obvious. I mean, coffee is supposed to keep you awake, right? Research confirms this, stating that having a cup of coffee right before bedtime can mimic the symptoms of insomnia. Maybe you could watch and episode of your favorite series for 45 minutes while you wait for the effects to wear off?


If you drink coffee on an empty stomach, chances are that you will have some symptoms of heartburn or an upset stomach. So, make sure to eat something before (or with?) your first cup of the day. Who needs a cranky tummy to suit their grumpy non-morning person mood, right?


If you drink coffee sparingly, it might alleviate your headaches. Unfortunately, drinking lots of coffee could lead to severe headaches and migraines. Not fun. Or, if you’re a total coffee addict, skipping a cup could also lead to some pretty nasty withdrawal headaches. Talk about a catch-22.

Reduces Female Fertility

If you’re trying to conceive, you might want to cut down on your coffee intake. Research shows that drinking coffee reduces a woman’s odds of conceiving by as much as 27%. Scary stuff.

Risk of Miscarriage

This one affects the men as well. If either mom or dad drinks at least two cups of coffee per day in the few weeks before conception, the risk of miscarriage increases

Caffeine Overdose

Some people are way more sensitive to caffeine than others. While cases of caffeine overdose are rare, they do exist and could lead to death. If you have any underlying medical conditions, you’re especially at risk of this. So, if you’re not used to coffee or if you’re overly sensitive to its effects, maybe take it slow during that next all-nighter.


Some people are allergic to caffeine. These unfortunate individuals react badly to coffee, developing hives, and suffering pain after they ingest even the tiniest amount of coffee. Sucks to be you, man.

Forceful Heart Contractions

After drinking coffee or any other caffeinated energy drink, your heart will contract more forcefully. If you have any underlying medical conditions, this could have some pretty severe consequences. If you’re healthy and have no other medical things going on, this might not have a long-term effect on you. The jury is still out on that one.

Worsens Menopause Symptoms

As if menopause isn’t bad enough, drinking coffee can worsen your symptoms. Sorry, ladies. If you want to ease those hot flushes and other nasties, you’ll have to forego your morning wake-up cup.

Ingesting More Sugar

This one can be prevented. I mean, you don’t have to add a ton of sugar or sweetener to your coffee, right? Because most people prefer having a slightly sweet cuppa Joe, drinking a lot of coffee increases their overall sugar intake. This could lead to developing Type II diabetes and becoming obese. So, as with all things, moderation is key.

In Closing

There you have it, folks. Coffee can make you sleepy, has fantastic health benefits and some not-so-awesome side effects. It seems that moderation is key here if you want the benefits while decreasing the side-effects. Did you notice any side effects with your morning brew?