Coffee makes the world go round, or so it seems. It’s such a typical sight in both popular culture and in real life to see folks grabbing a cup of coffee on the way to work.
And almost every workplace or office has a coffee machine in their break room where people go to refuel to continue working.
So that begs the very important question: how much coffee can you safely have during a workday?
How your body is affected by caffeine
Caffeine is a nervous system stimulant, which means it mainly affects the brain. Your brain produces a hormone called adenosine which makes you feel sleepy and relaxed.
The effect caffeine has on your brain is blocking the receptors in your brain from binding with adenosine, making you feel fresh for longer and giving you an energy boost.
Boosted energy is a result of adenosine receptors beginning to bind to adenosine, only to be interrupted by caffeine, so the relaxation program is shelved for a while as the brain fires up again.
There have been plenty of studies regarding the various effects caffeine has on your body – some bad, some good.
Here are some of the more interesting results:
- It can help improve your performance during exercise
- It can help you lose weight
- It may reduce the process and speed of liver damage
- It may reduce the risks of certain types of cancers
- It may increase the activity of beneficial gut bacteria
However, it’s not all roses – having too much caffeine has the following potential downsides:
- Overstimulating the brain results in confusion
- It can cause headaches
- It can cause irritability
- It can increase your blood pressure
- It can worsen your insomnia if you already suffer from it
- It can cause jitters
It is worth noting here that most of these effects are “it can” or “it may”, not “it will”. There’s a big difference and these are the results of certain studies that are far from conclusive evidence, though these certainly are indications.
As with anything else, coffee is best consumed in moderation to enjoy most of its benefits. Take the findings above with a grain of salt(pun intended), as there are other things we regularly eat and breathe that are far more likely to cause similar symptoms or results.
How your body processes caffeine
Caffeine is a comparatively small molecule so it can easily get through the various membranes in your digestive tract and into the bloodstream.
Within 45 minutes of consuming caffeine, nearly 99% of it will have been absorbed by your body. Within 4 to 6 hours, all of the caffeine will have broken down, and that’s when the effects will have worn off.
How well you metabolize caffeine is dependent on a few factors, but mostly your genes. The efficiency of the enzyme your body uses to break caffeine down is in your genes!
In case you’d like to read up a little more on this particular enzyme, it’s called cytochrome P450. The gene that codes for this enzyme is the CYP1A2.
In addition, there are some more factors which determine how well or fast your body processes caffeine.
Your liver is the most important organ for breaking down caffeine. Any liver problems will affect how your body breaks down caffeine.
Interestingly enough, studies have found that smoking nearly doubles the rate at which caffeine is broken down in the liver. I must point out here that the ill effects of smoking are much, much worse than the small benefit of possibly being able to drink more coffee!
There are a wide variety of foods that have different effects on caffeine metabolism. Grapefruit has been observed to slow down caffeine metabolism, whereas broccoli and Vitamin C in general have been observed to speed it up.
Pregnancy and other changes to the body will also have an effect. Obviously, pregnant women are recommended to have as little caffeine as possible as it can travel through the placenta into the baby’s bloodstream.
There are three types of people when it comes to caffeine:
- Hypersensitive: if you take a sip of coffee, you’ll lose an entire night’s sleep and feel jittery! This is rare, but you’ll know if this is you.
- Normal sensitivity: you can safely consume 200-400 mg of caffeine in a day without any ill effects. This is the average window of safe caffeine consumption, and most people fall into this category.
- Hyposensitivity: you can drink more than 500 mg of caffeine without any overdose symptoms, and can sleep well even if you have a cup right before bed. This is me! I once had a shot of espresso from an airport cafe just to stay awake on an upcoming flight and ended up falling asleep within minutes of boarding!
Caffeine in coffee
Here’s a quick rundown of the average amounts of caffeine in coffee.
- Espresso: about 100mg per 2 ounce shot
- Regular coffee: 150-200mg per 8 ounce cup
- Cappuccino/latte/macchiato: the same as an espresso, unless you have a double shot
These values are averages and will obviously depend on the kind of bean used. Per volume of coffee, lighter roasts tend to have more caffeine. Robusta beans(generally used in instant coffee) also have more caffeine than Arabica beans(generally used in higher quality coffees).
You should be aware that even decaf has 5-10mg of caffeine per 8 ounces, so while hypersensitive people may prefer to drink decaf, you’re not completely avoiding caffeine.
Caffeine during a work day
Assuming you have normal sensitivity and drink one cup of coffee during breakfast or on the way to work, on average, you have a window of about 3 more cups during the work day.
I’d like to point out here that a cup is in fact a US cup, or 8 ounces. If you drink 12 ounces of coffee in one go, that’s the same thing as 1.5 cups, so if you had 3 12 ounce servings of coffee, you’re effectively having 4.5 cups of coffee.
At this point, you’ll definitely go over the safe caffeine limit for most people, and if you add cream and sugar, you’ll also be consuming a lot of unnecessary calories.
Many coffee establishments serve specialty drinks that are guilty of this very thing. They’ll serve you a giant cup of coffee that’s loaded with caffeine, sugar, fat, and artificial sweeteners. Actually, the best kind of coffee is when there are as few additives as possible.
Most of the measurements of coffee caffeine content rely on a measurement of 8 ounces – just something to keep in mind.
What else contains caffeine?
Even if you’re controlling your coffee intake, there are a lot of other beverages that contain caffeine. If you were watching your coffee intake but downing a Red Bull or Monster on top of that, you’ll go over your caffeine limit.
Here’s a list of how much caffeine there is in some other popular beverages:
- Energy drinks: 50–160 mg
- Cocoa beverage: 2–7 mg
- Chocolate milk: 2–7 mg
- Yerba mate: 65–130 mg
- Brewed tea: 40–120 mg
- Soft drinks: 20–40 mg
Caffeine sensitivity is a spectrum rather than an exact number and you know your body best. Some people can drink 5 cups of coffee without feeling anything, and others can feel the effects in a single cup.
If you’ve been regularly drinking coffee for a long time, your body will have gotten used to caffeine and in most cases won’t affect you as much as it would others.