9 Side Effects of Too Much Caffeine



Coffee and tea are both extremely healthful drinks.

Caffeine is a stimulant that can improve your mood, metabolism, and mental and physical performance.

It’s also safe for most people when ingested in low-to-moderate amounts, according to studies.

High dosages of caffeine, on the other hand, can have unpleasant and even deadly adverse effects.

According to research, your genes play a significant role in your tolerance to it. Some people can eat a lot more coffee than others without getting sick.

Furthermore, folks who aren’t acclimated to caffeine may experience negative effects even after eating a low dosage.

Here are nine negative consequences of consuming too much coffee.


Caffeine has been shown to boost attentiveness.

It works by inhibiting the effects of adenosine, a neurotransmitter in the brain that causes fatigue. At the same time, it causes adrenaline, the “fight-or-flight” hormone linked to enhanced energy, to be released.

These effects may become more prominent with increasing doses, resulting in uneasiness and nervousness.

In fact, caffeine-induced anxiety disorder is one of four caffeine-related disorders included in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM).

Most people experience uneasiness, jitteriness, and other symptoms when they consume 1,000 mg or more per day, but caffeine-sensitive individuals may experience similar effects even with a small dose.

Furthermore, when ingested in one sitting, small amounts have been observed to produce fast breathing and elevate stress levels.

In one study of 25 healthy males, those who consumed around 300 mg of caffeine had more than double the stress levels as those who took a placebo.

Stress levels were equal among regular and seldom caffeine drinkers, suggesting that the chemical may have the same effect on stress levels whether you drink it regularly or not.

Nonetheless, these are tentative findings.

Caffeine concentration in coffee varies greatly. For comparison, a large (“grande”) Starbucks coffee has approximately 330 mg of caffeine.

If you find yourself feeling nervous or jittery frequently, you might consider reducing your caffeine intake.


One of caffeine’s most coveted features is its ability to keep people awake.

Caffeine, on the other hand, can make it harder to achieve adequate restorative sleep.

Caffeine use appears to lengthen the time it takes to fall asleep, according to studies. It may also cut down on total sleep time, particularly in the elderly.

Low to moderate doses of caffeine, on the other hand, do not appear to have much of an effect on sleep in persons who are considered “excellent sleepers,” or even those who have self-reported insomnia.

If you underestimate the amount of caffeine you consume, you may not notice that it is interfering with your sleep.

Caffeine is found in soda, cocoa, energy drinks, and a variety of medications, however, it is most concentrated in coffee and tea.

An energy shot, for example, can have up to 350 mg of caffeine, while other energy drinks can contain up to 500 mg per can.

Importantly, how much caffeine you can eat without disrupting your sleep is determined by your genetics and other factors.

Caffeine ingested later in the day, on the other hand, may disrupt sleep because its effects can take several hours to wear off.

According to studies, caffeine stays in your system for an average of five hours, but it can last anywhere from one and a half to nine hours depending on the individual.

One study looked into the effects of caffeine consumption on sleep. Twelve healthy people were given 400 mg of caffeine six hours before bedtime, three hours before bedtime, or right before bedtime.

The amount of time it took all three groups to fall asleep as well as the amount of time they were awake at night increased dramatically.

These findings show that if you want to get the most out of your sleep, you should pay attention to the amount and timing of caffeine you consume.

3.Digestive Issues

Many people find that a cup of coffee in the morning helps them move their bowels.

The release of gastrin, a hormone produced by the stomach that speeds up colon action, is thought to be responsible for coffee’s laxative effect. Additionally, decaffeinated coffee has been proven to have a similar effect.

Caffeine, on the other hand, appears to increase bowel motions by enhancing peristalsis, or the contractions that transport food through the digestive system.

It’s hardly surprising, then, that high dosages of caffeine can cause loose stools or even diarrhea in some people.

Despite the fact that coffee was once thought to induce stomach ulcers, comprehensive research of over 8,000 people found no link between the two.

Caffeinated beverages, on the other hand, have been linked to the worsening of gastroesophageal reflux disease (GERD) in some patients, according to some research. This appears to be especially true in the case of coffee.


Five healthy adults drank caffeinated water in brief research and noticed a relaxation of the muscle that prevents stomach contents from going up into the neck, a symptom of GERD.

If you’re having problems with your digestion, you might want to reduce your coffee intake or switch to tea.

4.Muscle Breakdown

Rhabdomyolysis is a potentially fatal disorder in which injured muscle fibers enter the bloodstream, causing renal failure and other complications.

Trauma, infection, substance misuse, muscle tension, and bites from deadly snakes or insects are all common causes of rhabdomyolysis.

There have also been a few instances of rhabdomyolysis linked to high caffeine consumption, albeit this is a rare occurrence.

After drinking 32 ounces (1 liter) of coffee containing around 565 mg of caffeine, a woman got nausea, vomiting, and black urine. Thankfully, she recovered after receiving medication and drinks.

Importantly, this is a large amount of caffeine to drink in such a short amount of time, especially for someone who isn’t used to it or who is really sensitive to its effects.

Unless you’re used to ingesting more caffeine, it’s advised to keep your caffeine intake to around 250 mg per day to avoid rhabdomyolysis.


Despite all of caffeine’s health benefits, it’s impossible to ignore that it has the potential to become addictive.

According to a comprehensive assessment, while coffee stimulates specific brain chemicals in the same way that cocaine and amphetamines do, it does not produce the same type of addiction.

However, especially at high doses, it can cause psychological or physical dependence.

In one study, 16 persons who normally ingested high, moderate, or no caffeine did a word test after going caffeine-free for an overnight period. Only people who drank a lot of caffeine had a predisposition towards caffeine-related phrases and had a lot of caffeine cravings.

Caffeine consumption frequency also appears to play a role in reliance.

In another study, 213 caffeine drinkers filled out questionnaires after going 16 hours without it. Headaches, lethargy, and other withdrawal symptoms were more common among daily users than in non-daily users.

Even though the molecule doesn’t appear to create actual addiction, if you consume a lot of coffee or other caffeinated beverages on a regular basis, you’re highly likely to become addicted to its effects.

6.High Blood Pressure

Caffeine does not appear to raise the risk of heart disease or stroke in the majority of persons.

However, because of its stimulating effect on the neurological system, it has been found in multiple trials to elevate blood pressure.

Because high blood pressure can damage arteries over time, reducing blood flow to the heart and brain, it’s a risk factor for heart attack and stroke.

Fortunately, the effect of caffeine on blood pressure appears to be transient. It also appears to have the greatest effect on those who aren’t accustomed to taking it.

Caffeine consumption has also been demonstrated to raise blood pressure during exercise in both healthy and slightly hypertensive patients.

Caffeine intake and timing must therefore be carefully monitored, especially if you already have high blood pressure.

7.Rapid Heart Rate

Caffeine has stimulant properties, which can cause your heart to beat quicker.

It may also cause atrial fibrillation, a type of irregular heartbeat that has been recorded in young people who have drunk energy drinks with exceptionally high caffeine levels.

In one case study, a lady who attempted suicide by taking a large dosage of caffeine powder and pills got an extremely fast heart rate, kidney failure, and other major health problems.

This effect, however, does not appear to be universal. Even some persons with cardiac problems may be able to take huge doses of caffeine without experiencing any negative side effects.

When 51 heart failure patients drank 100 mg of coffee per hour for five hours in a controlled trial, their heart rates and rhythms remained normal.

Regardless of the mixed study results, if you observe any changes in your heart rate or rhythm after drinking caffeinated beverages, cut back.

8 .Fatigue

Caffeinated liquids such as coffee, tea, and other caffeinated beverages are proven to increase energy levels.

They can, however, have the reverse effect, causing rebound fatigue once the caffeine has left your system.

Although caffeinated energy drinks increased alertness and improved mood for several hours, participants were generally more exhausted than usual the next day, according to a study of 41 trials.

Of course, you can avoid the rebound effect if you continue to consume large amounts of coffee throughout the day. However, this may interfere with your ability to sleep.

Caffeine should be consumed in moderate rather than large dosages to maximize its energy effects and avoid rebound weariness.

9.Frequent Urination and Urgency


Caffeine’s stimulatory actions on the bladder cause increased urination, which is a common adverse effect of heavy caffeine use.

You may have observed that when you consume more coffee or tea than normal, you need to urinate more frequently.

The majority of study on the compound’s effects on urine frequency has been conducted on the elderly and individuals with hyperactive bladders or incontinence.

12 young to middle-aged persons with hyperactive bladders who ingested 2 mg of caffeine per pound (4.5 mg per kilogram) of body weight on a daily basis reported significant increases in urine frequency and urgency, according to one study.

This equates to around 300 milligrams of caffeine per day for someone weighing 150 pounds (68 kg).

In addition, in persons with healthy bladders, increased intake may raise the risk of developing incontinence.

More than 65,000 women without incontinence participated in a big study that looked at the impact of increased coffee intake on incontinence.

When compared to individuals who ingested less than 150 mg per day, those who took more than 450 mg per day had a considerably higher risk of incontinence.

If you consume a lot of caffeinated beverages and notice that your urination is more frequent or urgent than it should be, cutting back on your intake to see if your symptoms improve is a smart option.

The Bottom Line

In many persons, light-to-moderate caffeine consumption appears to have significant health benefits.

On the other hand, very high doses might induce unpleasant side effects that can make daily life difficult, as well as major health problems.

Although reactions differ from person to person, the repercussions of excessive ingestion show that more isn’t always better.

To reap the benefits of caffeine without the drawbacks, evaluate your sleep, energy levels, and other elements that may be impacted, and lower your intake if necessary.

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