Now, adults are recommended to have up to 400 milligrams of caffeine per day, which is equal to about 2 cups of regular coffee, generally speaking. That said, the way your body reacts to caffeine may be different, and you may experience symptoms of caffeine overdose after having just one cup of coffee, or even just a cup of black tea. How do you know that you’ve had too much caffeine? It will be useful to look out for the 7 symptoms we list below.
1. Your stomach is upset
Most of us associate an upset stomach and abdominal cramps with the stomach flu, spoiled food, and foodborne illness, but research says that we should also include our morning cup of joe in that list. A study from 2017 pointed out that the bitter taste of coffee stimulates the production of stomach acid, which can thus increase the acidity in your stomach and potentially cause heartburn, acid reflux, and stomach pains.
Drinking coffee with cow's milk or plant-based milk could help neutralize that effect, so give it a try if coffee gives you any of the symptoms we've mentioned above. Of course, the best way to get rid of the problem is to stop drinking coffee altogether, so consider switching to tea, maybe?
2. Your heart is racing
A racing or fluttering heart is certainly a frightening symptom to experience, but before you run to the doctor, think about this, have you had any coffee a few hours prior to experiencing heart palpitations, by any chance? If so, coffee may be the cause, as excess caffeine in the blood may make your heart race or even make you dizzy.
And caffeine isn't the only stimulant capable of manifesting itself this way - nicotine and alcohol, too, can likewise cause heart palpitations. Therefore, it's advisable to cut off any of these substances if you wish to stop experiencing this symptom.
3. You're jittery and more irritable than usual
As we've mentioned earlier, too much of a good thing is certainly not healthy when it comes to coffee. When consumed in adequate amounts, coffee can have a stimulating effect on the central nervous system, as it binds to the dopamine receptors in the brain, making our mood better, increasing our alertness and focus, and even making us more motivated.
However, when the dopamine system is overstimulated by having too much coffee, things get less optimistic and you can start feeling jittery like you're hands are shaking and you have difficulty concentrating. In addition, coffee in excessive amounts can also make you more irritable than usual. It's important to watch out for these symptoms and determine how much caffeine is right for you to be alert but not jittery and irritated. This is true not only about drinking coffee but also other caffeinated beverages or foods.
4. You have diarrhea
Many people drink their morning coffee because they know that coffee can help keep them regular. Though the scientific mechanism behind this is poorly understood, it is widely known that coffee has laxative properties. Thus, if you have more than two or three cups of coffee a day, which is beyond the recommended daily amount, these laxative effects can be more pronounced and you may experience diarrhea as a result.
The solution? Gradually dial back the amount of coffee in your diet to 2 or fewer cups a day, or none at all if the issue persists. Cutting off the caffeine immediately isn't a good idea in most cases, though, as it can lead to constipation and withdrawal symptoms.
5. You have a headache
Speaking of withdrawal symptoms, drinking too much coffee in the morning, for example, and then not having any all evening can lead to something known as a caffeine headache. These headaches are moderate to severe and they are located on both sides of the head. The pain tends to worsen with physical activity.
This happens because caffeine can make the blood vessels shrink, which can actually reduce a headache and amplify the effect of pain-relief medications according to an article from The Journal of Headache and Pain. This is why many cold medications and pain relief drugs also contain caffeine. However, once you stop drinking coffee, the blood vessels in the head will dilate again, causing a headache. This pain will continue from a few days to a week or more if you don't consume more caffeine.
6. You can't fall asleep at the usual time
Coffee doesn't just make you more alert, it also makes you less sleepy, as coffee blocks the adenosine receptors, which are the receptors in your brain responsible for making you sleepy. This effect can last for hours (the half-life of caffeine is 5 hours, after that the effect will start slowly decreasing), which means that drinking coffee in the afternoon can seriously mess with your sleep cycles.
Apart from causing insomnia, which is a telltale sign of excessive coffee consumption, it can also make your sleep more sensitive or increase the number of times you wake up at night. So, it's best to drink your last coffee of the day at noon.
7. You're anxious
If things that you used to perceive more calmly are suddenly causing you a lot of anxiety, your coffee habit may be to blame. And while the process of drinking coffee may feel cozy or relaxing, the drink itself can actually amplify or otherwise contribute to anxiety. This is especially true in high-stress situations or difficult periods in one's life when you're more likely to ruminate at night.
These anxiety-inducing effects were exemplified in one study where regular coffee drinkers were given either placebo or caffeine before a stressful task. As a result, those who had coffee displayed a higher blood pressure, more stress hormones in their blood, and most notably, nearly twice the self-reported stress level compared to the placebo group. Although the sample size of the study included only men and was quite small, it's still an important display of what coffee could be doing to our stress levels. So, if you suffer from anxiety in general or only occasionally, consider drinking less coffee or ideally none whatsoever.
Share this important information with other coffee drinkers, too!