Side Effects of Excessive Caffeine Intake

You can feel great about drinking coffee or tea. Caffeine, found in most varieties, is thought to improve mood, metabolism, and cognitive and physical performance. Consumption at moderate to low doses has been shown to pose no health risks to the general population. However, some people experience uncomfortable and even dangerous side effects from consuming excessive amounts of caffeine. The extent to which you can tolerate it depends largely on your DNA, according to studies. Caffeine tolerance varies greatly among humans. Furthermore, even those who are acclimated to caffeine may feel the side effects of even a moderate dose after ingesting it for the first time. Caffeine intake of about 300 milligrams (mg) was associated with significantly higher stress levels in research including 25 healthy men.

Surprisingly, the level of stress of regular and seldom caffeine users was identical, suggesting that the chemical could have a similar impact on levels regardless of how frequently it is consumed. However, it should be noted that these are still preliminary findings. Caffeine concentration in coffee varies widely. As a point of comparison, the amount of caffeine in a grande (large) coffee from Starbucks is around 330 milligrams (mg). Reduce your caffeine consumption if you find that you are frequently anxious or agitated. The effects of coffee on sleep were examined in one study. Twelve healthy adults were given 400 milligrams of caffeine six hours, three hours, or just before night. In all three groups, people took noticeably longer to get to sleep and stayed awake for longer each night. According to these findings, optimizing your sleep requires paying attention to both the quantity and time of caffeine consumption.

Most people can use caffeine in their healthy diet without any problems. But there is a risk if you consume too much of it.

What are the side effects of excessive caffeine intake?

Caffeine’s side effects can be felt far more acutely by some individuals than by others. If you are experiencing the indicators of having had too much caffeine, you need to cut back on how much you are consuming. The impacts of anxiety after eating varying doses of caffeine were assessed in 57 separate experiments and analyzed together. The results were inconsistent regardless of whether the intake was low or large. According to one body of studies, drinking a maximum of five cups of coffee did not have any impact on levels of anxiety. According to the findings of other studies, simply 2 to 3 cups of coffee might cause sensations of tension. If you experience anxiety to any degree, whether it is mild or severe, it may be a sign that you are consuming too much coffee and that you should cut back.

The impacts of anxiety after eating varying doses of caffeine were assessed in 57 separate experiments and analyzed together. The results were inconsistent regardless of whether the intake was low or large. According to one body of studies, drinking up to five cups of coffee did not have any impact on levels of anxiety. According to the findings of other studies, simply two or three cups of coffee might cause sensations of tension. If you experience anxiety to any degree, whether it is mild or severe, it may be a sign that you are consuming too much coffee and that you should cut back.

When a person consumes more caffeine than what is considered to be a safe level, they run the risk of experiencing negative effects.

Following are the side effects of excessive caffeine intake

It’s common knowledge that caffeine makes people feel more alert. It does this by suppressing the effects of a chemical in the brain called adenosine, which is responsible for making you feel fatigued. At the same time, it causes the body to produce more adrenaline, which is the hormone associated with a “fight or flight” response and greater physical energy. These impacts, although, may become more evident with greater doses, which might result in feelings of worry as well as nervousness. It has been reported that intakes of 1,000 mg or more of caffeine per day can cause uneasiness, jitteriness, and other symptoms in most people. However, in caffeine-sensitive individuals, even small amounts of caffeine might contribute to the same consequences. When taken all at once, even very low doses have been observed to result in increased heart rate and breathing rate, as well as elevated levels of stress.

Unable to sleep

One of the most desirable aspects of caffeine is its ability to prolong wakefulness. However, it can be challenging to get enough restful sleep if you consume too much caffeine. Caffeine appears to prolong the time it to fall asleep, according to research. Lastly, it has the potential to shorten the amount of time spent sleeping, especially among the elderly. In contrast, “excellent sleepers” and even individuals who report chronic insomnia appear to be unaffected by moderate or even high levels of caffeine consumption. If the amount of caffeine you consume is underestimated, you might not know that it is preventing you from getting a good night’s rest. Caffeine can be found in a wide variety of foods and drinks beyond only espresso, and chai. For instance, some drinks have as much as 500 milligrams of caffeine per can, while a single energy shot may offer up to 350 milligrams.

Trouble Digesting Food

Some folks find that drinking coffee first thing in the morning helps them poop. Gastrin, a hormone produced by the stomach, stimulates action in the colon, which may explain why coffee has a laxative effect. Additionally, research shows that decaffeinated coffee has the same effect. Caffeine appears to increase peristalsis, the spasms that transport foodstuff through your digestive tract, which in turn stimulates bowel motions. Caffeine has this effect, therefore it’s not strange that some people get diarrhea after consuming excessive amounts of it. For a long time, it was thought that coffee caused stomach ulcers. However, a big study including over 8,000 patients found no such connection. If you’re having digestive problems, cutting back on coffee or switching to tea may help.

Inadequate Muscle Maintenance

Rhabdomyolysis is a life-threatening disorder in which fragments of muscle fibers are released into the bloodstream. This can lead to renal failure and other complications. Rhabdomyolysis can be brought on by several different things, including but not limited to physical trauma, infections, drug use, and overuse of muscles. Rhabdomyolysis has been linked to high levels of caffeine consumption, albeit cases of this are few. A woman who drank 32 ounces (1 liter) of coffee, or about 565 mg of caffeine, reported feeling sick, vomiting, and having dark urine. Medications and water helped, and she made a full recovery. For someone who isn’t used to caffeine or who is particularly sensitive to its effects, this is a very strong amount to drink in a short period. Unless you’re accustomed to more, you should not exceed 250 mg of caffeine per day to lower your risk of rhabdomyolysis.


There is no doubt that caffeine, despite its many positive effects on health, can have an addictive quality for certain people. But at high enough doses, it could cause serious psychological or physical dependence. In one study, participants (16 total) were divided into three groups based on their average caffeine intake: high (300 mg per day), moderate (300–600 mg per day), and no (0 mg per day). Those who regularly consume large amounts of caffeine are the only ones who have a preference for terms that refer to caffeine and intense desires for the substance. Caffeine dependence also appears to be related to how often people consume caffeine. In a second study, 213 caffeine consumers filled out surveys after being without the drug for 16 hours. To a higher extent than non-daily users, daily users saw a rise in withdrawal symptoms such as headaches and fatigue.


Caffeine consumption does not appear to raise the risk of cardiovascular disease or attack in the general population. However, multiple studies have indicated that due to its stimulating effect on the neurological system, it increases blood pressure. Inadequate blood supply to the heart and brain is one of the leading causes of death worldwide, and high blood pressure is a major contributor to this problem.

Urinating frequently

Caffeine’s stimulating effects on the bladder make frequent urination a common negative side effect of the drug. A common side effect of drinking more espresso or tea than usual is the urge to urinate more often. Urinary frequency is a common problem, especially for the elderly and persons with overactive bladders or incontinence, who have been the primary subjects of studies on the compound’s effects on the regularity of urination.

A rapid heartbeat

Caffeine is a stimulant, so too much of it could speed up your heartbeat. Furthermore, high-caffeine energy drink consumption has been linked to cases of atrial fibrillation in young adults. According to one research study, a woman who tried suicide by ingesting a large quantity of caffeine powder and pills experienced a fast heart rate, renal failure, and other major health problems. Not everyone appears to experience this impact, though. It’s possible that some people with cardiac conditions can consume significant amounts of coffee with no side effects.

One controlled trial found that after 51 individuals with heart failure drank 100 mg of coffee per hour for 5 hours, their heartbeat and rhythms returned to normal. If your heart rate or rhythm changes after consuming caffeinated beverages, irrespective of the contradictory research findings, you may want to cut back.

The Bottom Line

The health advantages of caffeine consumption, even at low to moderate levels, appear to be substantial. Conversely, overdosing might result in unpleasant side effects that disrupt normal life and could even be harmful to your health. The side effects of high intake show that more is not necessarily better, but individual reactions differ. If you want to reap the benefits of caffeine without suffering from its negative side effects, it’s important to take an honest inventory of your sleep, energy, and other characteristics that could be impacted by caffeine consumption and adjust your intake accordingly. Caffeine acts as a natural stimulant, influencing cognitive and physiological processes. Most people drink some sort of caffeinated drink every day, with espresso, chai, and soda taking the cake. Consuming coffee in moderation has been linked to better energy, mood, weight, cognitive, and physical performance. Caffeine’s side effects might vary greatly from person to person.

Caffeine is a stimulant, but too much of it can lead to negative side effects like headaches, anxiety, difficulty sleeping, pain in the chest, and frequent urination. Caffeine sensitivity varies widely from person to person, so some may experience these side effects at far lower amounts than others. Caffeine can trigger allergic reactions and modify the performance of some drugs. If you experience negative reactions to coffee, you may wish to cut back or abstain from it entirely. To cut back on caffeine consumption, try drinking more water and eating more fiber- and nutrient-rich foods like fruits, vegetables, nuts, and seeds. If you’re feeling uneasy on account of your coffee use, cutting back may assist. If you suddenly stop drinking coffee, you may have withdrawal symptoms proportional to how much caffeine you usually consume. Reducing intake gradually can help reduce or prevent these side effects.