Tea and coffee are two of the healthiest drinks you can drink.
Caffeine, found in most varieties, is thought to improve mood, metabolism, and cognitive and physical performance (1Trusted Source, 2Trusted Source, 3Trusted Source).
In addition, research has revealed that moderate to low doses are generally well tolerated by the human body (4Trusted Source).
However, some people have unpleasant and deadly side effects when taking large amounts of caffeine.
The extent to which you can tolerate it depends mainly on your DNA, according to studies. Some people can take far higher caffeine doses than others do (5Trusted Source, 6Trusted Source).
Furthermore, those sensitive to caffeine may feel ill even after drinking what is considered a low or moderate (4Trusted Source, 7Trusted Source).
Too much caffeine may cause the following nine symptoms.
1. The First Anxiety Attack
Caffeine has been scientifically shown to do just that.
Adenosine is a substance in the brain that contributes to feeling fatigued. Thus limiting its effects is how it works. Simultaneously, it causes the body to produce adrenaline, sometimes known as the “fight or flight” hormone (8Trusted Source).
However, these side effects may become more prominent with greater dosages, sometimes causing uneasiness and anxiety.
The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM) includes four caffeine-related disorders, one of which is a caffeine-induced anxiety disorder.
Although most people experience anxiety and jitteriness at intakes of 1,000 milligrammes per day or above, those sensitive to caffeine may feel the effects at lower doses (9, 10Trusted Source).
Consuming even a small amount in one sitting has been linked to increased tension and fast breathing (11Trusted Source, 12Trusted Source).
Caffeine intake of around 300 milligrammes was associated with significantly higher stress levels in research involving 25 healthy males.
Caffeine may have the same impact on stress levels regardless of how often you drink it since regular and infrequent users reported similar stress levels (12Trusted Source).
However, these findings are just preliminary.
Caffeine levels in coffee may vary widely—caffeine content-wise, a grande size coffee from Starbucks clocks in at about 330 milligrammes.
Are you feeling anxious or tense frequently? You may need to cut down on coffee.
2. Lack of sleep
One of the most significant benefits of caffeine is that it aids in maintaining wakefulness.
However, if you drink too much coffee, you can have trouble sleeping at night.
According to research, caffeine prolongs the time it takes to fall asleep. In the elderly, it may also lead to less sleep overall (13Trusted Source, 14Trusted Source).
In contrast, “excellent sleepers” and those who report chronic insomnia do not seem adversely affected by moderate or even modest caffeine use (15Trusted Source).
If you don’t give yourself a realistic caffeine intake target, you may not notice that caffeine prevents you from getting enough shut-eye.
Caffeine is most often associated with coffee and tea, but it may also be present in soda, chocolate, energy drinks, and certain medications.
Some energy drinks include as much as 500 mg of caffeine per can, whereas an energy shot may have as little as 200 mg (16Trusted Source).
It’s important to note that the quantity of caffeine you may eat without affecting your sleep will vary based on your genetics and other variables.
Caffeine’s after-effects may last for hours, disrupting sleep if drunk late in the day.
Caffeine has an average half-life in the human body of five hours but may linger anywhere from one and a half to nine hours, according to studies (17Trusted Source).
The effects of coffee on sleep were studied in one research. Twelve healthy people were given 400 milligrammes of caffeine six hours, three hours, or just before bedtime.
All three groups took noticeably longer to fall asleep and stayed up much longer each night (18Trusted Source).
These findings highlight the significance of the timing and quantity of caffeine used to achieve optimum sleep.
3. Tummy Troubles
Morning coffee is often used to stimulate intestinal activity.
Gastrin, a hormone the stomach produces, stimulates action in the colon, which may explain why coffee has a laxative effect. Additionally, research has revealed that decaffeinated coffee has the same product (19Trusted Source, 20Trusted Source, 21Trusted Source).
On the other hand, coffee seems to increase peristalsis, the contractions that drive food through your digestive system and promote bowel motions (21Trusted Source).
Caffeine has this effect. Therefore it’s not strange that some individuals get diarrhoea after consuming excessive amounts of it.
Although it was long thought that coffee caused stomach ulcers, massive research, including more than 8,000 patients, found no such connection (22Trusted Source).
However, some research suggests that caffeinated drinks may exacerbate GERD symptoms in specific individuals. This is particularly true in coffee (23Trusted Source, 24Trusted Source, 25Trusted Source).
One little research found that caffeinated water relaxed the muscle that prevents acid from the stomach from entering the oesophagus when five healthy people drank it. This muscular relaxation is characteristic of gastroesophageal reflux disease (25Trusted Source).
Limiting your coffee intake or switching to tea may help alleviate stomach problems caused by the beverage.
4. Loss of Muscle Mass
Damaged muscle fibres are released into the circulation, causing renal failure and other complications in a syndrome known as rhabdomyolysis.
Rhabdomyolysis may result from several different things, including illness, medication usage, infection, muscular tension, or even a bite from a venomous animal.
Even though cases of rhabdomyolysis caused by caffeine overdose are uncommon, there have been many instances of such illness (26Trusted Source, 27Trusted Source, 28Trusted Source, 29Trusted Source).
After consuming 32 ounces (1 litre) of coffee with around 565 mg of caffeine, one lady experienced nausea, vomiting, and black urine. Medications and water helped, and she fully recovered (29Trusted Source).
For someone who isn’t accustomed to coffee or particularly sensitive to its effects, this is a solid dose to ingest quickly.
If you’re not accustomed to drinking more than roughly 250 mg of caffeine per day, you should cut down to that amount to lower your risk of rhabdomyolysis.
Despite caffeine’s positive effects on health, it may nevertheless be addictive.
In-depth analysis reveals that, unlike cocaine and amphetamines, coffee does not lead to the same level of traditional addiction (30Trusted Source).
At high enough doses, however, it presents the risk of physical and mental dependence.
In one research, participants (16 total) were divided into three groups based on their usual caffeine intake: high (4), moderate (4), and no (0). High caffeine consumers were the only ones who preferred caffeine-related phrases and had severe caffeine withdrawal symptoms (31Trusted Source).
Another factor contributing to reliance is how often one consumes caffeine.
Two hundred and thirteen caffeine consumers participated in questionnaire research after becoming caffeine-free for 16 hours. Headaches, tiredness, and other withdrawal symptoms were more severe among daily users than infrequent users (32Trusted Source).
Although scientific evidence suggests that caffeine does not induce addiction per se, heavy coffee or energy drink consumers may develop a tolerance to the substance over time.
6. Chronic Hypertension
Caffeine use does not seem to elevate the risk of cardiovascular disease or stroke in the general population.
Multiple investigations, however, have demonstrated that its stimulating impact on the neurological system increases blood pressure (33Trusted Source, 34Trusted Source, 35Trusted Source, 36Trusted Source).
Because high blood pressure may damage arteries and reduce blood flow to the heart and brain, it is a risk factor for both conditions.
The beneficial effects of coffee on blood pressure are just transitory. Those not used to its products may feel them the most strongly.
Caffeine before exercise has increased blood pressure in healthy individuals and those with preexisting hypertension (37Trusted Source, 38Trusted Source).
As a result, those with hypertension should be careful about how much and when they consume coffee.
7. Seventh-Rate Heartbeat
Caffeine is a stimulant, so too much of it might speed up your heartbeat.
In addition, high-caffeine energy drink use has been linked to cases of atrial fibrillation in young adults (39Trusted Source).
A lady who tried suicide by ingesting a large quantity of caffeine powder and pills had severe heart palpitations, renal failure, and other complications (40Trusted Source).
But not everyone has this impact. Some individuals with cardiac conditions can drink a lot of coffee without experiencing adverse side effects.
Average heart rates and rhythms were maintained in controlled research, including 51 patients with heart failure who took 100 milligrammes of coffee every hour for five hours (41Trusted Source).
Despite the contradictory findings, you should reduce caffeine consumption if you have irregular heartbeats or a faster heartbeat after consuming caffeinated drinks.
Caffeinated drinks, such as coffee, tea, and energy drinks, are often used to increase alertness and productivity.
The problem is that as the caffeine wears off, it might cause you to feel even more tired.
Although consuming a caffeinated energy drink might make you feel more alert and cheerful for a few hours, one analysis of 41 research indicated that the effects wore off by the next day, and individuals were typically more exhausted than average (42Trusted Source).
Of course, you may prevent the rebound effect by maintaining a high caffeine intake throughout the day. However, this might disrupt your usual sleeping patterns.
Moderate rather than excessive caffeine consumption is preferable for maximising caffeine’s effects on energy and preventing tiredness return.
9. Urinary frequency and urgency
Caffeine’s stimulating effects on the bladder make frequent urination a typical negative side effect of the drug.
If you consume more coffee or tea than usual, you may have to go to the bathroom more often.
Those with overactive bladders or incontinence, as well as the elderly, have been the primary target of studies examining the compound’s effects on urine frequency (43Trusted Source, 44Trusted Source, 45Trusted Source).
There was a substantial increase in urine frequency and urgency in 12 patients with overactive bladders who ingested 2 milligrammes of caffeine for every pound of body weight (4.5 milligrammes per kilogramme of body weight) daily (44Trusted Source).
This amount of caffeine would equal roughly 300 mg daily for someone weighing 150 pounds (68 kg).
In addition, persons with healthy bladders may be more prone to incontinence if they consume large amounts.
The effects of excessive coffee consumption on incontinence were examined in extensive research, including more than 65,000 women who did not suffer from this condition.
Compared to those who took less than 150 mg, those who drank more than 450 mg daily had a far higher risk of incontinence (45 Trusted Source).
If you feel like you have to go to the bathroom more often or urgently than usual, and you consume a lot of caffeinated drinks, you may want to try reducing your consumption to see if it helps.
Many individuals report tremendous health advantages from light to moderate caffeine use.
However, overdosing may result in unpleasant side effects that can disrupt daily life and pose significant health risks.
Different people will have different reactions, but it’s clear that excessive use has negative consequences.
Caffeine may have positive and negative impacts on your body, so taking an honest inventory of how your substance use affects your sleep, energy, and other areas of your life is essential.