Right off the bat, we’re going to come clean: this not an article shaming people who enjoy coffee and other forms of caffeine.
In fact, experts agree that a reasonable amount has no harmful impact on most people and that coffee can even offer some health benefits. (More on that later.)
But even in safe amounts, caffeine is still a chemical and it is important to know the impact it can have on your body, especially if you overdo it. So, read on to get the buzz on your cup of joe. (We can’t promise this will be the last coffee pun.)
Believe it or not, caffeine is a drug
Caffeine has been called “the most popular psychoactive drug in the world,” a distinction it shares with alcohol. It is a naturally-occurring substance that can be found in over 60 plant species worldwide. The most common sources used by humans include coffee beans, tea leaves, kola nuts (used to flavor cola drinks), and cacao pods (used to make chocolate). Synthetic caffeine has also been developed for use in medicines and as a food additive in popular “energy” drinks.
Caffeine is classified as a central nervous system stimulant of the methylxanthine class. In other words, it can easily slip through the blood-brain barrier to
As a stimulant, caffeine interferes with the chemical processes that cause sleepiness and temporally tricks the brain into thinking, “Hey, guess I am not so tired after all.” By exciting neural activity, caffeine causes many to experience mental clarity and lift “brain fog.”
Finally, caffeine increases the production and release of other chemicals and neurotransmitters in the brain. In particular, you’ll feel the effects of increased
Caffeine triggers stress responses
Caffeine’s stimulating effects go beyond the brain, too, as the blocking of adenosine receptors sets off a powerful chain reaction. The pituitary gland interprets increased neural activity as a sign of potential danger, so it activates the “fight or flight” response, flooding your bloodstream with adrenaline. As a result:
- Your pupils dilate
- Your airways open wider
- Your heart rate increases
- Blood flow near the surface decreases
- Blood flow to the muscles increases
- Blood pressure rises
- Your liver releases sugar into the bloodstream for an added boost of energy
We also experience these triggers when undergoing stress and everything happening here is designed to give you the best chance of survival. But when you’re sipping your morning coffee (and not, say, outrunning a wild animal), you just register those effects as that little pick-me-up you needed.
Yes, you are probably addicted
As is the case with many drugs that produce a pleasurable effect, caffeine is habit-forming, physically, mentally and emotionally. And, like other addictive substances, many people need to consume more over time to achieve the same effects they used to get with a smaller dose.
However, as far addictive drugs go, caffeine’s hook is very mild at best. If you usually start your day with 1-2 cups of coffee and you don’t drink it the next, you’ll probably notice a headache around the forehead and temples within an hour or two of your normal intake time. You’ll probably feel groggy and possibly irritable as well. But in most cases, that’s usually as far as it gets. And if you ever decide to forego coffee altogether, you’ll most likely get past those withdrawals within a week.
There is such a thing as too much
While it’s not easy to do by drinking coffee, it’s definitely possible to overdose on caffeine if you combine various sources throughout the day. Caffeine pills are especially dangerous because of their concentration.
It’s important to note that caffeine has a half-life of about six hours. So, if you consume 200mg of caffeine at 8 a.m., you still have roughly 100mg in your system by 2 p.m. That’s why some people have difficulty sleeping if they drink a cup of coffee any time after mid-afternoon.
As with all drugs, the limits of safe caffeine consumption are based on body weight: the lower the body weight, the less of the drug is needed to start causing problems. That’s why children and underweight adults are especially vulnerable to caffeine overdose.
More than 150-200 milligrams of caffeine per kilogram of body weight is considered lethal. For a 100-pound child or young adult, that comes out to about nine grams of total caffeine. That would require drinking upwards of 45 cups of coffee, or roughly the same number of caffeine pills.
But even though the bar of lethal danger is high, the limit for adverse effects is significantly lower. Consuming more than the recommended amount of 400 milligrams a day can start to have negative effects on your system.
Note: If you are wondering what 400 milligrams of caffeine looks like, that is about four cups of coffee (eight ounces each), 10 cans of cola (12 ounces each) and two energy shots.
Drinking coffee has real health benefits
Most studies exploring the effects of caffeine have used coffee as the medium because it’s the overwhelming favorite among significant sources. Likewise, studies investigating the health benefits of drinking coffee generally use caffeinated coffee. So, it’s actually difficult to determine which positive benefits derived from the caffeine and which can be traced to other components in coffee.
Studies have shown that drinking caffeinated coffee can help relieve pain, reduce or relieve migraine headaches, reduce asthma symptoms and elevate mood. As a mental stimulant, it increases alertness, cognition and reaction speed. Because it combats fatigue, it improves performance on tasks that require vigilance like driving, flying, solving simple math problems and data entry.
Studies also indicate other impressive benefits:
- 80% drop in risk of developing Parkinson's disease
- 20% drop in risk for colon cancer
- 80% drop in the chances of developing cirrhosis
- 50% drop in the risk of developing gallstones
In some experiments, mice who received high doses of caffeine were protected from developing Alzheimer’s disease and saw a reduction in precancerous cell division. And, as noted earlier, many studies suggest that a daily coffee habit can even help you live longer.
The bottom line: When it comes to caffeine, moderation is key. There’s nothing wrong with enjoying your morning java and appreciating the jolt of energy and alertness it provides. Just be mindful of how much caffeine you consume in a day and make note of how your body reacts to it.
This article has been updated from a post originally published 1/29/20.