9 Negative Effects of Excessive Caffeine

9 Negative Effects of Excessive Caffeine

Studies have also demonstrated that when ingested at low-to-moderate levels, it is safe for most individuals. On the other hand, caffeine in large quantities may have unpleasant and even hazardous adverse effects.

9 Negative Effects of Excessive Caffeine

Coffee and tea are both very wholesome drinks. The majority of them include caffeine, which may improve your mood, metabolism, and mental and physical performance.

Studies have also demonstrated that when ingested at low-to-moderate levels, it is safe for most individuals.

On the other hand, caffeine in large quantities may have unpleasant and even hazardous adverse effects.

According to research, your genes significantly impact your tolerance to it. Some people can take far more caffeine than others without having harmful side effects.

Furthermore, those who aren’t acclimated to caffeine may have adverse effects after drinking what is usually considered a moderate quantity.

Here are nine of the negative consequences of excessive caffeine use.

Source - The Jakarta Post


Caffeine has been shown to improve attentiveness.

It works by inhibiting the effects of adenosine, a brain neurotransmitter that causes fatigue. Simultaneously, it causes the release of adrenaline, the “fight-or-flight" hormone linked to enhanced energy.

At greater dosages, however, these effects may become more apparent, resulting in anxiety and agitation.

Caffeine-induced anxiety disorder is one of four caffeine-related syndromes classified in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM).

Extremely high daily intakes of 1,000 mg or more per day have been documented to produce uneasiness, jitteriness, and other comparable symptoms in the majority of people, although even a modest dose may have similar effects in caffeine-sensitive individuals.

Furthermore, when ingested in a single sitting, small amounts have been demonstrated to promote fast breathing and an increase in stress levels.

In one research of 25 healthy men, those who consumed around 300 mg of caffeine had more than double stress as those who took a placebo.

Interestingly, stress levels were comparable across regular and less frequent caffeine consumers, indicating that the substance may have the same impact on stress levels regardless of whether you drink it on a regular or seldom basis.

Nonetheless, these are tentative findings.

Caffeine concentration in coffee varies greatly. A large (“grande") coffee from Starbucks has around 330 mg of caffeine.

If you often experience anxiety or jitter, it might be time to reconsider your caffeine consumption and reduce it.

Caffeine may boost alertness in low-to-moderate dosages, while higher levels might cause anxiety or edginess. Keep an eye on your own reaction to see how much you can take.


One of caffeine’s most appreciated properties is its ability to keep people awake. Caffeine, on the other hand, may make it harder to achieve adequate restorative sleep.

Caffeine tends to increase the length of time it takes to fall asleep, according to studies. It may also reduce overall sleeping duration, particularly in the elderly.

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

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

Although coffee and tea have the highest concentrations of caffeine, they may also be found in soda, chocolate, energy drinks, and certain medications.

An energy shot, for example, may have up to 350 mg of caffeine, whilst other energy drinks carry up to 500 mg per can.

Importantly, the quantity of caffeine you may ingest without interfering with your sleep is determined by your genetics and other variables.

Caffeine ingested later in the day, on the other hand, may interfere with sleep since its effects may take several hours to wear off.

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

One research looked at how the time of caffeine consumption impacts sleep. Researchers delivered 400 mg of caffeine to 12 healthy people 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 spent awake at night, rose dramatically.

These findings imply that it is critical to pay attention to both the quantity and timing of caffeine in order to maximise your sleep.

Caffeine may help you remain alert throughout the day, but it can also have a detrimental influence on the quality and amount of your sleep. To prevent sleeping issues, stop drinking caffeine by early afternoon.

Digestive Issues

Many individuals find that a cup of coffee in the morning helps them get their bowels going.

The laxative impact of coffee has been related to the release of gastrin, a hormone produced by the stomach that increases activity in the colon. Furthermore, decaffeinated coffee has been proven to have a similar effect.

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

Given this function, it’s not unexpected that high caffeine levels might cause loose stools or even diarrhoea in some individuals. Although coffee was long thought to induce stomach ulcers, comprehensive research of over 8,000 individuals found no relationship between the two.

Caffeinated drinks, on the other hand, may aggravate gastroesophageal reflux disease (GERD) in certain people, according to some research. This seems to be particularly true with coffee.

In short research, five healthy adults who drank caffeinated water noticed a relaxation of the muscle that prevents stomach contents from going up into the neck, which is a symptom of GERD.

Because coffee may have a negative impact on digestive function, you may wish to reduce your intake or switch to tea if you have any problems.

While modest to moderate quantities of coffee might enhance gastrointestinal motility, higher doses can cause loose stools or GERD. It is advisable to reduce your coffee consumption or switch to tea.

Muscle Breakdown

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

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

Furthermore, while rhabdomyolysis caused by high caffeine use is uncommon, there have been many accounts of it.

In one example, a lady had nausea, vomiting, and black urine after consuming 32 ounces (1 litre) of coffee containing around 565 mg of caffeine. She recovered, thankfully, after being treated with medicine and water.

Importantly, this is a substantial amount of caffeine to eat in such a short period of time, particularly for someone who is not accustomed to it or is very sensitive to its effects.

To lessen the danger of rhabdomyolysis, restrict your caffeine consumption to around 250 mg per day unless you’re accustomed to drinking more.

People who consume significant quantities of caffeine may get rhabdomyolysis or the breakdown of injured muscle. If you’re unsure about your tolerance, stick to 250 mg each day.

Substance Abuse

Despite all of the health advantages of caffeine, there is no disputing that it has the potential to become habit-forming.

According to a thorough examination, although coffee stimulates some brain chemicals in the same way that cocaine and amphetamines do, it does not produce classic addiction in the same manner that these drugs do.

However, excessive doses may cause psychological or physical dependence.

In one research, 16 people who generally drank a lot, a little, or no caffeine participated. after being caffeine-free throughout the night, they took part in a word test. Only caffeine addicts displayed a predilection for caffeine-related terms and intense caffeine cravings.

Furthermore, the frequency with which caffeine is used seems to have a role in reliance.

In another research, 213 caffeine enthusiasts were asked to fill out questionnaires after spending 16 hours without drinking it. The frequency of headaches, lethargy, and other withdrawal symptoms increased more for daily users than for non-daily users.

Even while the molecule does not seem to create actual addiction, if you consume a lot of coffee or other caffeinated drinks on a daily basis, there’s a strong possibility you’ll grow addicted to its effects.

In people who utilise substantial quantities of caffeine on a regular basis, going without caffeine for many hours may cause psychological or physical withdrawal symptoms.

High Blood Pressure

Caffeine does not seem to raise the risk of heart disease or stroke in the majority of individuals.

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

High blood pressure is a risk factor for heart attack and stroke because it may damage arteries over time, limiting blood flow to the heart and brain.

Caffeine’s influence on blood pressure seems to be transient. It also seems to have the greatest effect on those who aren’t accustomed to ingesting it.

Caffeine consumption has also been demonstrated to increase blood pressure during exercise in both healthy adults and those with modestly high blood pressure.

As a result, paying attention to caffeine intake and timing is critical, particularly if you already have high blood pressure.

Caffeine seems to boost blood pressure when eaten in large quantities or before exercise, as well as in individuals who drink it seldom. However, this impact may only be momentary, so it’s essential to keep an eye on your response.

Rapid Heart Rate

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

It may also cause an irregular pulse rhythm known as atrial fibrillation, which has been recorded in young individuals who took exceptionally high caffeine dosages of energy drinks.

In one case study, a lady who attempted suicide by ingesting a large amount of caffeine powder and pills experienced an extremely high heart rate, renal failure, and other major health problems.

This impact, however, does not seem to be universal. Indeed, some people with cardiac issues are able to handle high doses of coffee without experiencing any negative side effects.

In one controlled trial, 51 heart failure patients who received 100 mg of coffee each hour for five hours maintained normal heart rates and rhythms.

Regardless of the mixed research findings, if you observe any changes in your heart rate or rhythm after consuming caffeinated drinks, you should consider cutting down.

Summary: Caffeine in high dosages may cause an increase in heart rate or rhythm in certain persons. These effects seem to differ widely across individuals. If you see them, try lowering your consumption.


Caffeinated beverages such as coffee, tea, and energy drinks are well recognised to increase energy levels.

They may, however, have the reverse effect by causing rebound weariness after the caffeine has left your system.

According to one evaluation of 41 studies, whereas caffeinated energy drinks boosted alertness and mood for several hours, individuals were often more exhausted than normal the next day.

Of course, if you continue to consume large amounts of coffee throughout the day, you will prevent the rebound effect. On the other side, this may have an impact on your capacity to sleep.

Caffeine should be used in moderate rather than large dosages to maximise its energy advantages and minimise rebound weariness.

Caffeine offers energy, but it may also contribute to exhaustion as the effects wear off. Aim for modest caffeine consumption to reduce rebound tiredness.

Urgency And Frequent Urination

Because of the stimulatory effects of caffeine on the bladder, increased urination is a typical adverse effect of excessive caffeine use.

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

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

One research found that 12 young to middle-aged adults with hyperactive bladders who ingested 2 mg of caffeine per pound (4.5 mg per kilogramme) of body weight daily reported substantial increases in urine frequency and urgency.

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

Furthermore, in people with healthy bladders, increased consumption may raise the probability of developing incontinence. One major research examined the impact of excessive caffeine consumption on incontinence in over 65,000 women who did not have 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 drinks and notice that your urine is more frequent or urgent than it should be, you should reduce your consumption to see if your symptoms improve.

In multiple studies, high caffeine consumption has been associated with increased urine frequency and urgency. Reducing your consumption may help to alleviate these symptoms.

The Bottom Line

Caffeine use that is light to moderate seems to have significant health advantages in many individuals.

On the other hand, excessively high doses may induce adverse effects that interfere with daily life and may even cause major health problems.

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

To get the advantages of caffeine without the negative side effects, examine your sleep, energy levels, and other elements that might be impacted, and lower your consumption if necessary.



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