8 Side Effects of Consuming Too Much Caffeine

Some forms of beverages contain caffeine, a drug that can boost your mood, mental efficiency, and metabolism. Studies have also shown that intake in low-to-moderate quantities is healthy for most people. Many people consume much more caffeine than others without having negative effects. People who are not used to caffeine may experience symptoms after consuming what we typically consider a moderate dose. Here are 8 side effects of consuming too much caffeine.

1. Insomnia

One of its most valuable attributes is the power of caffeine, which can help people stay awake. It’s hard to get enough restorative sleep while consuming too much caffeine. Studies have found that consuming too much caffeine seems to increase the time to fall asleep [1], [2]. It may also reduce total sleep time for elderly people. An energy shot, for example, contains up to 350 mg of caffeine, while some energy drinks provide as much as 500 mg per can [3].

It depends on your genes and other factors of how much caffeine you can drink without disrupting your sleep. Caffeine ingested in the evening can interfere with sleep because it may take several hours to wear off its effects. Study has shown that caffeine stays in your body for an average of five hours [4]. The time could vary from one hour to nine hours.

One study examined the effects of caffeine on influencing sleep timing. Researchers gave 400 mg of caffeine to 12 healthy adults either six hours before bedtime, three hours before bedtime, or just before bedtime. All three participants struggled to fall asleep, and the time they spent awake at night increased [5]. These results suggest it is important to pay attention to the timing of consuming caffeine to optimize your sleep.

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Caffeine lingers in your body for an average of five hours, but this can range from one to nine hours. Caffeine used in the evening might disrupt sleep because its effects can take several hours to wear off and possibly cause insomnia.

2. Muscle Breakdown

Rhabdomyolysis is a potentially life-threatening syndrome that reaches the bloodstream by breaking through muscle fibers, leading to kidney failure and other complications such as toxicity. Some cases of rhabdomyolysis have been reported because of consuming too much caffeine, although this is rare [6], [7], [8], [9]. In one instance, after drinking 32 ounces of coffee containing around 565 mg of caffeine, a woman experienced nausea, diarrhea, and dark urine. After being provided with drugs and fluids, she recovered [9].

This is a large dose of caffeine that can be absorbed in a brief time, for someone who is not used to it or who is sensitive to its effects will usually experience symptoms. To reduce the risk of rhabdomyolysis, it is best to limit your consumption to 250 mg of caffeine per day.

Large doses of caffeine may cause rhabdomyolysis, which is a potentially fatal syndrome caused by skeletal muscle fibre breakdown and leaking of muscle contents into the circulation.

3. High Blood Pressure

In most cases, caffeine does not appear to increase the risk of heart disease or stroke. Because of its stimulating effect on the nervous system, however, it has been shown to increase blood pressure in several studies [10], [11], [12], [13]. High blood pressure is a risk factor for heart attack and stroke because it can damage the arteries, reducing blood flow to your heart and brain.

The effect of caffeine on blood pressure is temporary. For healthy people and in those with elevated blood pressure, consuming too much caffeine can increase blood pressure during exercise [14], [15]. Therefore, it is important to pay attention to the dosage and timing of caffeine, if you have high blood pressure already.

Caffeine has been shown in multiple studies to raise blood pressure. High blood pressure puts you at risk for a heart attack or stroke.

4. Frequent Urination

Greater urination is because of the stimulating effects of the compound on the bladder, which is a common side effect of consuming caffeine. You may have noticed that when you drink more coffee or tea than usual, you need to urinate more frequently. Some studies have concentrated on older people and those with overactive bladders or incontinence to investigate the effects of the compound on urinary frequency [16], [17], [18].

However, one study found that 12 young to middle-aged adults with overactive bladders who ingested 2 mg of caffeine per pound (4.5 mg per kg) of body weight daily reported significant increases in urine frequency and urgency [17]. This equates to around 300 mg of caffeine per day for someone weighing 150 pounds (68 kg). In people with healthy bladders, increased intake may raise the probability of developing incontinence.

In over 65,000 women without incontinence, one comprehensive study investigated the effects of high consumption of caffeine on incontinence. Those who consumed over 450 mg of caffeine a day had a higher risk of incontinence compared to those who consumed less than 150 mg a day [18]. When you consume a lot of caffeinated beverages and find your urination is more frequent or urgent, decreasing your caffeine intake may be an excellent idea to see if your symptoms are decreasing.

Caffeine consumption may increase the likelihood of developing incontinence in adults with healthy bladders.

5. Anxiety

One of the psychoactive effect of caffeine is that it increases alertness. This works by blocking adenosine’s influence, a brain chemistry that makes you feel tired. Similarly, caffeine enhances neural activity in the brain, which the pituitary gland perceives as an emergency and stimulates the adrenal glands to release adrenaline hormone, which increases energy [19]. Such symptoms, however, may become more intense at higher doses of caffeine, resulting in anxiety and nervousness.

In addition, anxiety disorder caused by caffeine is one of the caffeine-related syndrome. A daily intake of 1,000 mg and more per day in most people have been documented to cause nervousness, jitteriness and similar symptoms, whereas even low intakes may lead to similar effects in people sensitive to caffeine [20], [21]. When ingested in a single sitting, small amounts developed fast breathing and an increase in stress levels [22], [23].

In one study of 25 healthy males, those who consumed around 300 mg of caffeine had more than twice the stress as those who took a placebo. Interestingly, stress levels were comparable across regular and less frequent caffeine consumers, implying that the chemical may have the same effect on stress levels regardless of whether you drink it on a regular or irregular basis [23]. It may be an excellent idea to look at your consumption of caffeine and cut it back if you find that you often feel nervous.

A large cup of coffee contains approximately 300 mg of caffeine. They have shown low-to-moderate doses can cause anxiety, jitteriness, and other symptoms in some people. 

6. Digestive Issues

A morning cup of coffee makes many people move their bowels. They attributed the laxative effect of coffee to gastrin release. The stomach produces this hormone to speed up activity in the colon. However, decaffeinated coffee has showed to produce the similar effect [24], [25], [26]. Similarly, caffeine appears to increase bowel motions by enhancing peristalsis, or contractions that move food through your digestive tract [26].

It is not surprising that, in some people, consuming too much caffeine can lead to lost stools or even diarrhea. While they thought coffee can cause stomach ulcers for many years, there was no correlation between and ulcers and coffee in one study of over 8,000 people [27]. According to some studies [28], [29], [30], caffeinated beverages may exacerbate gastroesophageal reflux disease (GERD) in some people.

This appears to be true of coffee. In one small study [30], five healthy adults who drank caffeinated drinks noticed a relaxation of the muscle that prevents stomach contents from going up into the esophagus, which is a common symptom of GERD. While coffee has major effects on digestive function, if you have any complications, cut back on how much you drink or change to tea.

Caffeine overdose can cause loose stools or even diarrhoea.

7. Fatigue

We understand that coffee, tea, and other caffeinated beverages raise energy levels. It may also have the opposite effect, however, by causing exhaustion after caffeine withdrawal from the body. A study found that while caffeinated energy drinks increased alertness and improved mood for several hours, the following day participants were often more tired than usual [31]. You can stop the withdrawal effect if you continue to drink plenty of caffeine throughout the day, which can also affect your sleeping capacity. Use it in the moderate rather than high doses to maximize the benefits of caffeine on energy and prevent caffeine withdrawal symptoms.

Caffeinated drinks such as coffee, tea, and energy drinks increase energy levels but can also induce fatigue, which is often called caffeine withdrawal symptoms.

8. Addiction

The caffeine in coffee and tea is a stimulant drug, which can become habit-forming. According to a detailed review [32], while caffeine activates some brain chemicals similar to cocaine and amphetamines, it does not induce classic dependence in the manner in which these substances do. It may, however, lead to psychological or physical dependency at high doses. In one study [33], 16 people who consumed high to moderate, or no caffeine, took part in a word test after being caffeine free for the night.

Only caffeine addicts displayed a bias for caffeine-related words and had significant coffee cravings. The frequency with which they used caffeine appears to play a role in dependency. Another study in 213 caffeine consumers [34], after 16 hours without drinking coffee, regular caffeine consumers had higher rates of headaches, exhaustion, and other signs of withdrawal than non-regular users. While the compound does not seem to cause true dependence if you drink a lot of coffee daily. You may become dependent on its effects.

Caffeine is a psychoactive substance that can become habit forming when used regularly.


Moderate consumption of caffeine provides many people with remarkable health benefits. Consuming too much caffeine can cause side effects. This can interfere with everyday life and may even cause serious health problems. Although responses differ from person to person, results suggest a high intake of caffeine is not better.

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