Most of us are getting fewer hours of restful sleep than we used to. Getting to work on time and being at our productive best sometimes requires stimulation.
If you’re like 80% of American adults, caffeine makes it into your body daily (1). Be it through good old coffee, tea, energy drinks, soda, or caffeine pills; the widely used stimulant can have side effects.
However, before we can jump into the adverse side effects of caffeine, let’s take a look at how it helps.
The Benefits of Caffeine
While many researchers disagree, caffeine is believed to boost overall performance and cognitive function in the body (2). If consumed in moderation and as a part of a healthy diet, caffeine may help you battle fatigue and stay more alert throughout the day. Some studies say that caffeine is linked to longevity as it helps prevent the onset of diseases like Parkinson’s, Alzheimer’s, Type 2 Diabetes, and even liver disease (3).
Additionally, this commonly occurring stimulant can boost moods and even positively impact your metabolism. Studies show that caffeine is safe for most people when consumed in a low-to-moderate frequency (4).
Research shows that genetics plays a huge role in determining a person’s tolerance to caffeine (5). This means that while some people can do well with 3 cups of coffee a day, some others have a lower tolerance threshold. Additionally, if someone isn’t used to consuming caffeine-rich foods, they may experience side effects after consuming what is typically a smaller dose of the stimulant.
The Negative Effects of Caffeine
Let’s take a look at the negative side effects of too much caffeine.
1. Increased Anxiety
People who end up consuming caffeine in large amounts tend to feel jittery, anxious, or nervous as a result of the stimulant’s effect. Caffeine is known to boost alertness and counter sleepiness. Since it blocks adenosine, a chemical that is produced in the brain and regulates the feeling of tiredness, it prevents you from feeling the fatigue.
Additionally, caffeine stimulates your brain to release more adrenaline (6). Adrenaline is the hormone that is associated with energy levels and the fight-or-flight response. When combined, caffeine’s effects help you pull that all-nighter or take that early morning flight without fail.
With that being said, if you take a higher dose of caffeine, it could lead to these effects manifesting becoming more pronounced. This can lead to nervousness, anxiety, or jitters.
If a person consumes over 1,000 mg or more of caffeine daily, it can cause extreme nervousness, anxiety, or jitteriness related to too much caffeine consumption (7). Again, if someone has a lower tolerance threshold for caffeine, they may feel these unpleasant side effects of caffeine at a much smaller dose.
Subsequently, according to some studies, modest doses can also cause rapid breathing or increase overall stress levels if consumed in a short time, or one go (8).
In one study conducted among a sample of 25 healthy men, it was found that the subjects who ingested around 300 mg of caffeine had greater stress levels as compared to those who were given the placebo. However, the stress levels of those who consumed caffeine regularly and those who did so less frequently were reasonably similar. This suggests that the stimulant may impact stress levels irrespective of the regularity of consumption. (9).
None the less, since these results are still in the preliminary stage, we have to consider the bigger picture. Most people get their daily caffeine from coffee. In any case, coffee’s caffeine levels can differ depending on a variety of factors. Right from what type of coffee beans are used to the method of preparation and the beverage you choose, you caffeine intake could be on the higher or lower side of the daily recommended limit.
While measuring the amount of caffeine you consume each day may be stressful, it may be wise to cut back if you feel jittery, anxious, or nervous throughout the day.
2. Raised Blood Pressure
If you have ever gone to get your blood pressure checked at the doctor, you may have been advised to stay away from your regular morning coffee. Most medical professionals will encourage you to avoid coffee or other caffeinated foods before getting your blood pressure checked.
This is standard advice that comes from the widely-accepted notion that caffeine causes a spike in blood pressure that may cause inaccurate measurements. However, an Italian study showed the opposite to be true (10).
Scientists took into consideration these diverging views and studied it again. The Swiss and American scientists engaged in the study of 15 volunteers chose healthy non-smokers. Out of these, only six were consuming coffee habitually. None of these volunteers had hypertension or high blood pressure (11).
The study found that caffeine raised blood pressure in people who weren’t accustomed to consuming it. However, regular coffee drinkers didn’t seem to be profoundly affected. Moreover, the study found that younger volunteers were more likely to be sensitive to coffee, especially caffeine found in the brew. Since habitual coffee consumers were acclimatized to the caffeine content, it didn’t cause a sharp rise in their blood pressure. Most subjects saw an increase of a point or two, at most.
It was found that caffeine could lead to a rise in blood pressure in those who already had hypertension. This was also observed among those who weren’t accustomed to drinking coffee.
3. Can Cause Insomnia
Restful sleep is among the most critical factors for a healthy body and mind. Research shows that regularly getting a good night’s sleep can effectively reduce stress. Additionally, sleep can improve memory, lower blood pressure, maintain a healthy weight, and promote overall good health (12).
However, in these digital times, when none of us go without our phones, getting distracted before bedtime is natural. If you throw in caffeine-rich beverages to the mix, you may have trouble falling asleep. Since caffeine is a stimulant, it blocks adenosine receptors in the body. Adenosine promotes the feeling of sleepiness, so when its production is blocked, you’re less likely to feel drowsy (13).
Upon being ingested, caffeine will reach its peak in the bloodstream within 30 to 60 minutes. The stimulant’s half-life (the time it takes to be eliminated from your body) is around 3 to 5 hours. So while most of the caffeine in your system will be removed within 5 hours, individual biochemistry can cause varied results.
As per another study conducted on the subject, it was found that coffee consumed 3 to 6 hours before bedtime can cause disturbances in falling asleep (14). The results of the same study recommend that caffeine use should be avoided up to 6 hours before sleeping to avoid any sleep pattern disturbances. Consequently, people with insomnia who have trouble falling asleep might experience an even more pronounced version of their effects if they consume too much caffeine.
4. Can Cause Pregnancy Complications
As we have already mentioned earlier, caffeine can hide in many foods right from beverages like tea and coffee to soft drinks and even some over-the-counter drugs. While caffeine usually exits the body in six hours, pregnancy can cause a slowdown in this process. Some studies on the subject found that caffeine during pregnancy can cause preterm birth, reduced birth weight, growth restrictions, and stillbirth (15).
Moreover, it was found that the fetus can absorb caffeine as the placenta absorbs it. Your adult body may not face any significant effect from caffeine, but your growing baby may not fully metabolize the caffeine. Additionally, even small amounts of caffeine can cause changes to the baby’s sleep patterns. It may hamper standard movement patterns in the later stages of pregnancy, increasing the chance of risk factors (16).
In a study conducted by The American Journal of Obstetrics and Gynecology, it was found that pregnant women who consumed over 200mgs of caffeine daily were more likely to have miscarriages than those who refrained (17).
5. May Affect Fertility
It is a widely accepted fact that semen quality is reducing among men worldwide. When coupled with lifestyle factors, stress levels have caused us all to experience fertility problems collectively. Even women aren’t immune to this phenomenon.
This study found that while caffeine-rich beverages like coffee and tea were relatively safe, caffeine from cola and other soft drinks were likely to impact semen concentration, count, and volume. Excessive coffee consumption was also found to be associated in a prolonged time to conceive in some cases (18).
Another study found that women who consumed over five cups of coffee regularly were more likely to take longer to conceive. However, it is hypothesized that other lifestyle choices and variables may have something to do with this. Based on similar research, Canadian healthcare practitioners advised drinking no more than two cups of coffee’s worth of caffeine in a day. This comes to around 300 milligrams of caffeine in a day. Your daily caffeine intake will also have to account for other foods like soda, cola, and even some kinds of dark chocolate with high caffeine presence (19).
6. May Cause Gout
Gout is a type of inflammatory disease which leads to uric acid buildup in the joints and tendons that cause immense pain. In the last few decades, the overall frequency of gout attacks has increased by up to 45%.
A study found that people who binged on caffeine-rich foods were more likely to suffer from gout attacks. The same study highlighted that those who deviate from the average amount of caffeine they consume daily to have a more massive dose suddenly are more likely to develop gout (20).
It is recommended that you switch to water or natural fruit juice instead of sugary caffeine-rich beverages as a preventative measure against gout.
7. May Trigger Heart Attacks
We already established that caffeine may end up interfering with healthy blood pressure. However, research on the subject shows that caffeine consumption may trigger heart attacks.
The study found that people who consumed coffee in moderate amounts (up to three cups a day) were up to 60% more likely to suffer a heart attack. However, light coffee drinkers were even more at risk. With every additional cup, the risk of heart attack increasers almost four times.
Additionally, for those who already had risk factors for heart disease (obesity, smoking, low activity, etc.), the risk of sustaining a heart attack more than doubled (21).
Since caffeine causes temporary boosts to blood pressure, those who suddenly ingest too much might feel a sharp surge in blood pressure. This may end up being a fatal blow to an already vulnerable cardiovascular system. Experts also reported that people with genetic variations associated with delayed caffeine metabolism were more likely to be at risk of nonfatal heart attacks upon consuming caffeine-rich beverages like coffee (22).
8. May Cause Your Bones to Become Brittle
Having a robust skeletal structure makes sure you’re not affected by disorders such as arthritis or osteoporosis. While women are more likely to suffer from calcium-loss related disorders and diseases, we can’t deny that more and more men are having these problems. Experts recommend that you take a diet that is rich in calcium and Vitamin D to prevent your bones from becoming weak.
However, new research shows that consuming too much caffeine can cause your bones to become weak or brittle (23). While caffeine is believed to leech out calcium from the body, it is thought that phosphorus present in caffeine-rich sodas may be partly to blame (24).
The study found that while caffeine itself didn’t directly cause osteoporosis or brittle bones if you were already deficient in calcium, it intensified the situation. Furthermore, although tea contains a certain amount of caffeine, it was found to be less damaging than caffeine-rich coffee.
9. May Increase Risk of Breast Tissue Cysts
Some researchers believe that caffeine may not directly cause fibrocystic changes that lead to tissue cysts. However, many experts believe that large doses of caffeine can cause hormone level changes that may lead to breast pain or even an increased risk of breast cysts (25).
Another study on the subject found that women who consumed between 30 to 250 mg of caffeine a day were over 1.5 times more likely to develop fibrocystic disease. Those who consumed over 500 mg of caffeine a day were two times more likely to develop breast tissue cysts (26).
10. Can Lead To Early Death
Without a doubt, coffee is among the most caffeine-rich foods in the world. However, if you want to live longer, the finding of a new study may spell bad news for regular coffee drinkers.
The study found that people under 55 who consumed more than four cups of coffee each day were at higher risk of dying early. While heart disease is a significant risk factor, the report suggests that early death referred to death from all causes, not just cardiovascular deaths (27).
Another partnered study by the Mayo Clinic found that younger people were more likely to die from caffeinated beverage use than older people. Additionally, the study found that men who drank more than four cups of coffee were up to 21% more susceptible to all-cause mortality (28).
11. Can Increase Risk of Heart Attack Among Young Adults
You may have come across someone who believes that coffee and other caffeinated beverages are like a death sentence to teens. Funnily enough, they may not be wrong.
A recent study on the subject found that young adults who had mild hypertension were almost four times more likely to have a heart attack if they consumed the equivalent caffeine of four cups of coffee. Consequently, those who were drinking more amounts of coffee in a day needed higher assistance to maintain and managing the symptoms (29).
12. May Cause Dry Skin
Dry skin can be a telltale sign of what is wrong with your body. Most commonly, it points towards a lack of proper hydration in the body. When t comes to your skin, everything you ate or drink will directly impact its health.
Two of the most harmful beverages in the case of dry skin are alcohol and caffeinated beverages, including soda and coffee. Since these are diuretic stimulants, they lead to frequent urination, and consequently, they deplete the body of hydration.
While you may reason that drinking water will correct this loss, you may be mistaken. Studies show that even if you remain hydrated, consumption of large amounts of caffeine can deplete the body’s cells of moisture, leading to problems such as dry, flaky, or patchy skin (30).
13. May Cause Urinary Incontinence
Also known as Overactive Bladder, urinary incontinence is a disorder where the person feels sudden urges to urinate that may lead to loss of bladder control. While many factors can lead to this, one crucial consideration is fluid intake and the volume of the same.
Another critical factor that can aggravate the disorder is caffeine. Caffeine can irritate the bladder and exacerbate the symptoms of incontinence. This is why experts recommend that you stop drinking caffeine-rich beverages like coffee, tea, sodas, etc. (31).
Another study showed that women who consume more caffeine that is recommended are up to 70% more likely to develop incontinence (32).
14. Can Harm Those with Type 2 Diabetes
Research suggests that people who have type 2 diabetes react differently to caffeine. If they consume too much caffeine, it can raise insulin and blood sugar levels in such patients.
One study found that people with type 2 diabetes who took 250 mg caffeine at breakfast and lunch had up to 8% more blood sugar than when they didn’t have any caffeine. They hypothesize that this is a result of how caffeine affects the body’s response to insulin (33).
Another study found that caffeine impacted and interfered with glucose metabolism among those who had type 2 diabetes (34).
15. May Aggravate Acid Reflux and Heartburn
When it comes to acid reflux or heartburn, what you choose to put in your body has a significant impact on your symptoms.
For GERD (acid reflux), experts recommend that you stick to your personal tolerance for caffeinated beverages like tea or coffee. If you aren’t used to drinking strong coffee, for instance, suddenly consuming it may aggravate your disorder (35).
Coffee has been observed to relax the lower esophageal sphincter causing an increase in the instances of acid reflux and heartburn. Some studies pinpoint towards caffeine as the culprit (36).
Another study found that people who consumed caffeine, especially caffeine-rich beverages, were more likely to suffer from indigestion. This was even more pronounced when the participants consumed these beverages on an empty stomach (37).
16. May Cause Migraines or Chronic Headaches
A new study suggests that people who consume too many caffeinated beverages are more likely to suffer from migraines. Researchers found that people who suffered from migraines, were more likely to get them if they regularly consumed more than three caffeinated drinks (38).
Another study found that while occasionally consuming caffeine was not harmful, overusing the stimulant can increase the occurrence of chronic daily headaches (39).
17. You Can Overdose on Caffeine
More and more products today contain caffeine than ever before. Thanks to the fact that we as consumers are ingesting more caffeine, most of us have developed a tolerance for this stimulant. However, some people may have developed sensitivity to this stimulant.
While there are sporadic cases of people overdosing on caffeine, it is still a possibility. Some individuals with underlying medical conditions are best advised to stay away from caffeine as it can cause death in exceptional circumstances (40).
18. Caffeine Allergies Can Have Unpleasant Side Effects
If you have a sensitivity to caffeine, you aren’t alone. More and more people seem to be developing sensitivity to the stimulant in recent times.
Some people who are overly sensitive to caffeine may end up with allergic reactions like a breakout of hives on the body and redness. While it isn’t a true food allergy like peanuts or shellfish, some people find that they suffer from adverse side effects even if they consume caffeine in small amounts.
Other reported symptoms of such an allergy include feeling jittery, fatigued, irritable, depressed, and a sharp lack of concentration (41).
19. May Cause Dehydration
Caffeine is a diuretic that can intensify the rate at which your body loses hydration. Dehydration can cause serious health problems and even affect your moods. This is why doctors ask that you limit your caffeine consumption to the recommended amounts.
Some studies conducted on the subject found that caffeinated drinks such as coffee, cola, soda, and even energy drinks can dehydrate you if not supplemented by other fluid intakes (42).
20. May Over stimulate the Bowel
Some diehard coffee enthusiasts swear by their morning cup of Joe. Some others have gone so far as to claim that they can’t go to the bathroom in the morning unless they have their coffee first.
When you drink something in the morning, caffeinated or not, it stimulates a defecation reflex. This gastrocolic reflex prompts you to have a bowel movement (43). While this may be helpful in cases where a laxative effect is desirable, it may not be useful in case you have loose motions or an upset stomach.
21. Aggravates Menopause Symptoms
Research studies show that there is a link between caffeine use in women and corresponding vasomotor symptoms. Additionally, the research suggests that if you are suffering from hot flashes that usually accompany menopause, you should cut back or eliminate caffeine from your diet (44).
22. Increases The Risk Of Fractures
We already spoke about how caffeine is a culprit when it comes to affecting bone health. According to this study, it was found that there may be a link between increased bone mass loss and caffeinated beverage consumption. While those who were under the daily recommended limit were not at risk, those who consume too much caffeine should be careful (45).
Another study found that caffeine use interferes with ossification and may be linked to a higher risk of fractures. While these findings are primarily dependent on individual dosage, heavy caffeine consumers should take care (46).
23. May Cause Weight Gain and Obesity
We agree that caffeine by itself isn’t going to make you gain fat. However, it is essential to acknowledge that most caffeinated foods and beverages come packed with extra sugar and additives.
Sugary foods are highly likely to make you gain weight and suffer from severe diseases like diabetes and raised blood pressure (47). To avoid this indirect side effect of consuming too many caffeinated beverages, try to cut back on your daily intake. Additionally, switch to natural and sugar-free alternatives.
24. May Inhibit Collagen Production
One study conducted on the subject found that those who exceeded the daily recommended limit of caffeine for prolonged periods were more likely to experience a dip in collagen production (48).
Since coffee inhibits the metabolizing of prolidase, it also hampers collagen biosynthesis in the body. Moreover, it was found that coffee drinkers had higher cortisol levels, prompting further interference to collagen biosynthesis (49).
25. Caffeine Worsens Prolonged Sleep Deprivation
Usually, we’re able to pull through a late night with some coffee or a potent energy drink to tide us through. However, according to a recent study, in the case of prolonged sleep deprivation, caffeine may only worsen the experience (50).
It was found that caffeine tends to give those with sleep deprivation a false sense of security. It wasn’t effective in actually making subjects more alert after three days of sleeplessness.
The Best Caffeine-Free Alternatives
Let’s take a look at some of the best caffeine-free alternatives you can incorporate into your diet to combat the negative side effects of overusing caffeine.
1. London Fog Tea Latte
The London Fog tea latte is a great caffeine-free alternative that mixes traditional English Earl Grey tea with steamed milk. Not only is it a simple beverage to recreate at home, it also can be made using dairy-free milk substitutes.
2. Nut Milk
Be it almond, cashew or even hazelnut, nut milk is a great substitute for animal milk as well as caffeinated beverages. Nut milk is nutritious, dairy-free, great for your weight loss endeavors and loaded with vitamins.
3. Golden Milk Lattes
If you’re looking to boost your intake of super foods, the golden milk latte is surely worth the effort. Using a premade spice mix, the average golden milk latte contains turmeric, cardamom and even ginger. These ingredients help fight the flu, boost immunity, improve digestive health and act as anti-inflammatory agents.
4. Lemon Juice and Water
A glass of warm water with lemon juice has a host of health benefits. Right from weight loss and digestion, to detoxification and its refreshing ability, this concoction is another great substitute to your morning cup of joe!
5. Organic Coffee
While organic coffee may or may not be decaffeinated, it is still better than regular coffee from a health standpoint. If you are looking to decrease the caffeine you consume on a daily basis, decaf organic coffee is a great alternative.
By now, you must have understood one thing for sure – as far as caffeine goes, moderation is the key. In most cases, people who stick to drinking the equivalent of two to three cups’ worth of caffeine won’t suffer from any significant side effects. However, with that being said, it is recommended to reduce caffeine intake if you feel any adverse side effects.
For best results, you can switch to non-caffeinated beverages like smoothies, natural fruit juices, or good old water. Even safer looking alternatives to coffee, such as matcha tea (51), have caffeine in them. This is why we recommend reading labels and making conscious choices daily.
If you currently consume more caffeine than the recommended limit, you should gradually decrease the amount you consume instead of quitting cold turkey. Similarly, if you are an avid coffee drinker, try switching to decaf or organic coffee. Not only are these likely to have less caffeine, but they may also have other health benefits.
Sarah is an Austin Native who has always loved the athletic side of herself. She ran track in college, but then once her professional life began, she saw her fitness levels drop considerably. She is a researcher who has a PhD in Food and Nutrition from McGill University in Canada. After graduating, she started a career as a researcher with the country's top food brands. Her career as a consultant for a leading health food brand for over a decade has made her believe in the power of a healthy lifestyle, and it also acts as her vision board for Big Blue Test’s future. Sarah has been practicing Muay Thai for the last four years, and her meditation sessions are known to be among the fiercest experiences among our team. At Big Blue Test, she acts as our mentor and helps us steer in the right direction.