Caffeine overdose: Top 15 symptoms you need to know


A coffee drink is an essential morning routine for millions around the globe. I won’t lie, I love it too. However, coffee contains caffeine, which is sadly an addictive drug. And like a drug, taking too much of it has its risks.

But did you know that you can suffer from an overdose of caffeine? Ooh, you didn’t? I thought so.

To keep you within the safe drinking limits, I have put together this article on caffeine overdose symptoms. In this way, you will be able to tone the uptake down when you reach the red light.


Symptoms of Caffeine Overdose

The stimulant and addictive caffeine have a consumption limit, beyond which it becomes a health risk. The recommended intake is 400 to 600 mg caffeine a day to keep adults healthy.

But with a serving of cappuccino or small latte containing about 100 to 200 milligrams of caffeine, you have to watch your intake. Any uptake above the 400-mg limit could cause an overdose, exposing you to a host of adverse health effects.

Knowing when you have reached the limit is therefore critical before you take the morning double shot and coke for lunch. Stay safe as you watch out for these symptoms.

1.      Shallow and Rapid Breathing

According to research done by Carnegie Mellon University, an overdose of caffeine causes increased blood pressure. This pressure increase stimulates shallow and rapid breathing. As you take the shallow breaths, your brain is deprived of the required amount of oxygen to function properly.

Insufficient oxygen in the brain then makes your thinking irrational. What this means is that after you have a couple of too much coffee, and you start having trouble taking breathes, then you could overdose on the caffeine.

However, the shortness of breath can be due to other reasons altogether apart from caffeine. Asthma and anxiety are also known causes of shallow and rapid breathing. If you don’t have any of these, then you need to taper down your caffeine intake. Do not suddenly cut it off.

2.      Increased Adrenaline

A surge in caffeine in your body triggers the body into releasing the adrenaline hormone. It is the hormone that is responsible for the “flight and fight” response in most of us. When it sets in, you feel the rush to get into a defensive and aggressive mood.

When you have been having tea, coffee, coke or an energy drink when you feel the urge to flee for the woods or fight when faced with a threat, then know you have had too much. The Adrenaline makes you make a rush into irrational decisions without considering any alternatives.

If you are a coffee regular and you start feeling your body going into a hyper-aroused mode, then you could be experiencing an overdose of caffeine.

3.      Insomnia or Having Trouble Sleeping

First of all, I think a good number of people do take a caffeinated drink due to their ability to keep you awake and alert. While it works wonders for you in this respect, an overdose would then keep away the sleep when you need it.

Insomnia worsens, more so if you have been having or is prone to sleeping disorders. In extreme cases where you do manage to fall asleep, the high caffeine levels disrupt the body’s hormone balance which maintains the natural wake and sleep cycles.

The caffeine would then be disrupting the Rapid Eye Movement (REM) stage of sleep, which is when your body is recuperating and processing emotions.

Excessive caffeine increases the frequency of your trips to the loo to pee. These trips interfere with your sleep if they are at night.

Inasmuch as you need to work overtime to meet certain deadlines, having an adequate amount of sleep is critical for any system. You end up needing more of the caffeine the next day.

Before you take any caffeinated drink, remember it has a half-life of six hours. For a comfortable sleep, take a drink at least 6 hours before you go to sleep.

4.      Increased Anxiety

First of all, if you are an anxious person, you should not drink coffee in the first place. The caffeine in the coffee in a way makes your anxiety levels go off charts. Sadly, if you have an overdose of caffeine, then you could experience anxiety either way.

This symptom disregards your past emotional history.  In fact, these symptoms might even be similar to those experienced in a panic attack. You become nervous, stressed and experience fear as you increase the caffeine ingestion.

5.      Increased Urine Discharge

It might sound counterintuitive, as most of you think that any drink replenishes your fluid levels. However, beyond some drinking limits, caffeine does the opposite. Instead of topping up the number of fluids in your body, you would be discharging it, since caffeine is diuretic.

The more you urinate, the thirstier you feel, and then the more dehydrated your body becomes. As you are well aware, dehydration is potentially dangerous, and can even be fatal if gone unchecked.

Research and studies also show that the drinking of any caffeinated drink does not meet the fluids demands of your body. Instead, they increase the fluid output (urination). So, if you have thought of taking your coffee during an intense exercise, think again.

Besides considerable dehydration, caffeine is thought to deplete certain essential nutrients from your body. Some of these include Vitamin B and C, Potassium, Magnesium, Zinc, and Calcium.

6.      Nausea and Dizziness

Feeling lightheaded, unbalanced and woozy is common of for someone who is experiencing an overdose of caffeine. These conditions are the symptoms of being dizzy. What differentiates normal dizziness from that from an overdose is the accompanying feeling of being nauseated.

Caffeine in the body increases stomach acid levels in one’s body, creating the feeling of an upset stomach and sometimes heartburn sensation. The nausea you feel is also as a result of your body feeling dehydrated.

In extreme cases of caffeine overdose, your body reacts as if it is experiencing food poisoning. It, therefore, does everything to rid itself of the “toxins.” And vomiting is one of the ways the best knows best how to use to make you toxin-free.

7.      Feeling an Urge to Poop

Sounds kind of weird and far-fetched, right? Well, apparently not so. Statistics indicate that about 30% of we humans have the urge to poop after having too much caffeine. For some people, it does not have to be an overdose at all. Just a cup and off to the toilet you go.

Invasive studies show that the caffeine in coffee tends to stimulate the distal colon into pushing out the poop. Alternatively, the chlorogenic acid in coffee raises the levels of stomach acid and gastric acid.

The acid rise hastens the digestion speeds, making the stomach release the byproducts of digestion as soon as possible. The bowel movements are also sped up by the release of digestion-aiding hormones.

Don’t worry if you don’t have the same feeling as it only happens in 3 out of 10 people.

8.      You Experience Jitters

Coffee drinkers normally experience this a lot when the effects of caffeine sets. Occasional trembling sensations, shaking hands and triggered reflexes are an indication of an overdose of caffeine.

As the caffeine reaches your brain, it acts as a stimulate for alertness. However, in excess amounts, these stimuli manifest as jitters, which is an unwelcome feeling. After a drinking spree, you start feeling uneasy and nervous about your surroundings.

You can make the feeling subside by taking a snack (has to be light) and drinking a couple of glasses of water.

9.      Becoming Extremely Paranoid

Have you ever felt like your brain was taking you to some quite dark places as you take a caffeinated drink? It is true that caffeine tricks your brain into a state of paranoia, where you start believing in these wild conspiracy theories.

There is an explanation for this feeling. Research has it that caffeine levels affect the dopamine transmission. More caffeine means the body produces more of this hormone. Excess dopamine levels lead to psychosis such as paranoia.

For you to start being paranoid, the intake has to be in excess levels. The symptoms can also be exuberated if you are normally paranoid even without the caffeine. The condition is not common as only about 3 to 6% of the heavy coffee drinker’s populace experience it.

10.  Rambling Speech and Thought

Caffeine overdose interferes with a lot of your other senses, with speech and thought to be the most susceptible and obvious. The stimulating effects of caffeine make you have rumbled speech, even you did not have any speech problems before.

These become problematic if you were to make a presentation or hold an important meeting. You would stay alert, but with an incoherent speech and thoughts, making for a terrible day at work.

11.  Increased Headache

A correlation does exist between high caffeine levels and the feeling of piercing headaches. Caffeine beyond the drinking limits increases the pressure in your brain, resulting in a headache.

In addition to this, the combination of a diuretic and stimulating properties pulses through the body, the brain receptors become overloaded. The overloading results from the brain having to coordinate too much-increased body activities at the same time, due to stimulation.

The net result is feeling headaches that you only have after taking tea, coke or that energy drink. Interestingly, some of the over the counter remedies for a headache also contain caffeine as an active ingredient. Ironical, right? But it’s probably the low amounts that make them effective.

12.  Experiencing Hallucinations

If you happen to consume about seven cups of coffee (instant coffee), then you are very likely to experience hallucinations. You start hearing and seeing voices and sounds that are non-existent. The intensity of these experiences varies with the amount of caffeine intake.

According to research, these hallucinations are as a result of intensified physiological stress. During this stressful period, caffeine causes the release of cortisol. It is this cortisol that is thought to trigger hallucinatory experiences.

When you start having weird thought and hearing voices in your head, then know that you have too much coffee for the day.

13.  You Start Experiencing Stomach Ulcers

Excessive amounts of caffeine cause an increased amount of gastric acids in the stomach, speeding up digestion in the process. Both coffee and caffeine contribute to a rise in the serum gastrin levels. All these then combine to speed up the rate of emptying of the stomach contents.

The result is that you have excessive movements of highly acidic contents through the small intestines. The speed is rather faster than usual. The high speeds injure the intestinal wall and tissues in the process.

The injuries caused and the high acidity all contribute to you developing ulcers as a result of too high caffeine levels.

14.  Caffeinism induced Coma

Sounds scary, but in the most extremes, a caffeine consumer can have what is called caffeine intoxication. This condition, makes you disoriented and confused at the same time.

It is in this state that caffeine-induced coma occurs, and even seizures.

Well, coffee in itself is quite unlikely to stimulate and trigger commas and seizures. However, there is a story of an Ohio student who ingested 100% of caffeine powder in excess amounts. Sadly, the student ended up dying after experiencing seizures and irregular heartbeats.

15.  Cardiac Arrests

The stimulating effects of caffeine increase the blood supply pressure in one’s body. Too much caffeine takes the body into overdrive, as the adrenaline levels increases.

If you have a weak heart, handling the high pressure becomes a tall order, then you experience cardiac arrests as a result. This symptom could be very devastating for you, but I hope you don’t experience it.



I hope reading this article has been an absolute joy for you, as well as being helpful in being in the know of the side effects of too much caffeine. Caffeinated drinks are important in our daily lives, and like everything else, there exists positives and negatives of caffeine.

What is important is being able to tell how much is too much caffeine, as well as the symptoms. In this way, you enjoy the best of both worlds. You keep taking your favorite drink and be healthy as always.

If there is any symptom that you have ever experienced and I left it out, please hit me up in the comments section below as you share this article with your friends. Thank you.

You can take in more of Kathy’s Coffee knowlege over at


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