We’ve been hooked on caffeine for ages — more than 3,000 years at least. The stimulant was first discovered in China around 1,000 BCE, according to our earliest records of people drinking a beverage made from Camellia sinensis leaves. Since then, tea, coffee and other caffeinated drinks have become an integral part of daily life in most cultures. More than 90 percent of the global population consumes caffeine every single day.
You’ve probably seen (and perhaps ignored) myriad scary headlines about the perils of consuming caffeine, and perhaps just as many extolling its virtues.
So, what’s the deal? How much caffeine is too much, and how can you tell if you need to cut back? We talked with doctors to understand how caffeine works in the body and to separate the facts from the myths when it comes to this popular stimulant.
Caffeine 101
Caffeine seems to be everywhere. You can find it in tea, coffee, hot chocolate, soda, energy drinks and many other beverages. Most of us experience extra alertness after drinking a cup of coffee or another form of caffeine.
That’s because “caffeine increases your heart rate and triggers the release of adrenaline and cortisol, along with increased dopamine signaling, making you feel alert and ready for action,” says Dr. Chester Wu, a psychiatric and sleep medicine physician in Houston.
While it’s working its magic, caffeine blocks adenosine receptors — the signals in our brain that tell us when to rest. But eventually, that effect wears off, causing that familiar crash.
“Sometimes you’ll feel even more tired than before, as adenosine has been building up in the background,” Wu says.
Caffeine has the potential to be addictive as users continually seek the dopamine release that caffeine triggers in the brain.
A cup of hope
When used responsibly, caffeine has its benefits, no matter where you find it.
“Caffeine can boost mental and physical performance, and reduce risk of injury or error,” Wu says. Research has found that caffeine can enhance problem-solving skills, and its use has been linked with safer driving among truck drivers.
Certain caffeinated drinks, like coffee and tea, have specific health benefits.
“Coffee contains plenty of antioxidants, and it has health benefits like protecting you from type 2 diabetes, cancer and Alzheimer’s disease,” Wu says. “There’s even a reported association between coffee consumption and lowered risk of suicide.”
Tea consumption has been linked to similar health benefits, and caffeinated treats like dark chocolate can potentially help lower blood pressure, enhance mood and provide key minerals.
Research has also found that moderate amounts of caffeine can provide benefits like improved athletic performance and treatment for headaches.
In hot water
The verdict on caffeine isn’t all bad, but that’s not a free pass to consume as much as you want. Too much can cause increased heart rate, heart palpitations and symptoms of anxiety, says Dr. Ryan Peterson, an anesthesiologist and addiction specialist in Los Angeles.
Many medical professionals suggest sticking to a maximum of 400 mg a day, the equivalent of four or five eight-ounce cups of coffee. That limit could be significantly less if you’re sensitive to caffeine, pregnant or breastfeeding, or dealing with certain health conditions like high blood pressure.
If you already have a high level of anxiety, it might be good to stay away from caffeine altogether, as it can put your body into fight-or-flight mode.
“When consumed in low or moderate doses, like one to two cups per day, caffeine is generally safe,” says Peterson. “However, just like any substance, when caffeine is abused, tolerance can be reached.”
If you depend on caffeine to function and you have a hard time cutting back, you may have caffeine use disorder, which is marked by unsuccessful attempts to cut back, high caffeine tolerance and withdrawal symptoms. But even if you aren’t overdoing it, some people are more sensitive to caffeine than others.
“You might be consuming too much of it for you if you notice you get anxiety or nervousness, jitters, dizziness or headaches, an upset stomach, a fast heart rate and frequent urination,” Peterson says.
It’s also important to be mindful of when you caffeinate so you don’t mess with your natural sleep cycle. This accounts for all caffeine sources, not just coffee and tea but also hot chocolate and energy drinks. Even decaf coffee contains a small amount of caffeine.
“Many underestimate how long caffeine stays in our system,” Wu says. “Because caffeine can last upwards of 12 hours, even an early afternoon cutoff time is too late in the day for many.”
Spilling the beans
How can you tell if you’re dependent on caffeine? If you feel lethargic or weak when you can’t get your fix, that’s a sign of dependence.
Perhaps you’re sensitive to caffeine and just want to see what happens if you eliminate the habit. Whatever your reasons for cutting back, don’t quit cold turkey. Caffeine withdrawal is real and can affect people who are used to consuming a lot on a regular basis.
“Start with small baby steps in removing caffeine, such as only taking half the usual dose you’re taking,” Peterson says. “This is to avoid withdrawal symptoms such as fatigue, headache, irritability, confusion and even depression.”
Even if totally quitting caffeine isn’t your goal, taking an audit of your consumption and staying mindful of your intake can help you find a happy medium while still enjoying your favorite brew.